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reaction kinetics and galactooligosaccharide product profiles of the β-galactosidases from bacillus circulans, kluyveromyces lactis and aspergillus oryzae.β-galactosidase enzymes are used in the dairy industry to convert lactose into galactooligosaccharides (gos) that are added to infant formula to mimic the molecular sizes and prebiotic functions of human milk oligosaccharides. here we report a detailed analysis of the clearly different gos profiles of the commercial β-galactosidases from bacillus circulans, kluyveromyces lactis and aspergillus oryzae. also the gos yields of these enzymes differed, varying from 48.3% (b. circulans) to 34.9% (k. l ...201728193420
position 228 in paenibacillus macerans cyclodextrin glycosyltransferase is critical for 2-o-d-glucopyranosyl-l-ascorbic acid synthesis.the markedly stable l-ascorbic acid (l-aa) derivative 2-o-d-glucopyranosyl-l-ascorbic acid (aa-2g) has been widely used in the fields of food, medicine, cosmetics, and husbandry. cyclodextrin glycosyltransferase (cgtase) is considered suitable for the large-scale production of aa-2g. in this work, paenibacillus macerans cgtase was used to produce aa-2g and the production was 13.5g/l. an amino-acid sequence alignment of α-, β-, and α⁄β-cgtase indicated that the phe at position 228 of p. macerans ...201728219734
synthesis of an allergy inducing tetrasaccharide "4p-x".4p-x (β-d-galactopyranosyl-(1 → 4)-β-d-galactopyranosyl-(1 → 6)-[β-d-galactopyranosyl-(1 → 4)]-β-d-glucopyranose) is included in galacto-oligosaccharides (goss) produced by β-galactosidase derived from bacillus circulans. 4p-x has been known to induce particularly strong allergies. high purity 4p-x is essential for use as a standard to quantify the amount of 4p-x in goss; however, the isolation of high purity 4p-x has never been reported. in this study, we achieved the synthesis of 4p-x by a com ...201728107656
stabilization of bacillus circulans xylanase by combinatorial insertional fusion to a thermophilic host protein.high thermostability of an enzyme is critical for its industrial application. while many engineering approaches such as mutagenesis have enhanced enzyme thermostability, they often suffer from reduced enzymatic activity. a thermally stabilized enzyme with unchanged amino acids is preferable for subsequent functional evolution necessary to address other important industrial needs. in the research presented here, we applied insertional fusion to a thermophilic maltodextrin-binding protein from pyr ...201728100651
structure-activity relationships on the study of β-galactosidase folding/unfolding due to interactions with immobilization additives: triton x-100 and ethanol.improving the enzyme stability is a challenge for allowing their practical application. the surfactants are stabilizing agents, however, there are still questions about their influence on enzyme properties. the structure-activity/stability relationship for β-galactosidase from bacillus circulans is studied here by circular dichroism and activity measurements, as a function of temperature and ph. the tendency of preserving the β-sheet and α-helix structures at temperatures below 65°c and differen ...201727965126
synthesis, characterization and biological studies of schiff bases derived from heterocyclic moiety.some new schiff bases (h1-h7) have been synthesized by the condensation of 2-aminophenol, 2-amino-4-nitrophenol, 2-amino-4-methylphenol, 2-amino benzimidazole with thiophene-2-carboxaldehyde and pyrrole-2-carboxaldehyde. the structures of newly synthesized compounds were characterized by elemental analysis, ft-ir, (1)h nmr, uv-vis, and single crystal x-ray crystallography. the in vitro antibacterial activity of the synthesized compounds has been tested against salmonella typhi, bacillus coagulan ...201727894775
simultaneous decolorization of sulfonated azo dyes and reduction of hexavalent chromium under high salt condition by a newly isolated salt-tolerant strain bacillus circulans bwl1061.the co-existence of dyes, cr(vi) and high concentration of salt in dyeing wastewater causes serious and complex environmental problems. in this study, a salt-tolerant strain bacillus circulans bwl1061 was reported to simultaneously remove 50mg/l methyl orange and 50mg/l cr(vi) under the anaerobic condition with 60g/l nacl. during the decolorization process, the cr(vi) reduction occurred preferentially over the dye decolorization due to the dominate utilization of electron by cr(vi). the analysis ...201728284151
immobilized trienzymatic system with enhanced stabilization for the biotransformation of lactose.the use of ketohexose isomerases is a powerful tool in lactose whey processing, but these enzymes can be very sensitive and expensive. development of immobilized/stabilized biocatalysts could be a further option to improve the process. in this work, β-galactosidase from bacillus circulans, l-arabinose (d-galactose) isomerase from enterococcus faecium, and d-xylose (d-glucose) isomerase from streptomyces rubiginosus were immobilized individually onto eupergit c and eupergit c 250 l. immobilized a ...201728241449
engineering of the bacillus circulans β-galactosidase product specificity.microbial β-galactosidase enzymes are widely used as biocatalysts in industry to produce prebiotic galactooligosaccharides (gos) from lactose. gos mixtures are used as beneficial additives in infant formula to mimic the prebiotic effects of human milk oligosaccharides (hmos). the structural variety in gos mixtures is significantly lower than in hmos. since this structural complexity is considered as the basis for the multiple biological functions of hmos, it is important to broaden the variety o ...201728092444
[activation of biosynthesis of guanyl-specific ribonuclease secreted by bacillus circulans under salt stress].the gene transcription of guanyl-specific ribonucleases (rnases), which provide available phosphate to cells of bacillus, is controlled by the signal transduction system phop-phor. however, the biosynthesis of b. circulans rnase does not depend on the signal-transduction regulatory proteins of pho regulon. it has been found that raising the salt molar concentration in culture medium increases the level of extracellular guanyl-specific ribonuclease bci synthesized by b. circulans. sequences homol ...201728064315
refolding the unfoldable: a systematic approach for renaturation of bacillus circulans xylanase.xylanases are important polysaccharide-cleaving catalysts for the pulp and paper, animal feeds and biofuels industries. they have also proved to be valuable model systems for understanding enzymatic catalysis, with one of the best studied being the gh11 xylanase from bacillus circulans (bcx). however, proteins from this class are very recalcitrant to refolding in vitro. this both limits their high level expression in heterologous hosts, and prevents experimental approaches, such as peptide ligat ...201728466501
the structure of rbmb from streptomyces ribosidificus, an aminotransferase involved in the biosynthesis of ribostamycin.aminoglycoside antibiotics represent a classical group of antimicrobials first discovered in the 1940s. due to their ototoxic and nephrotoxic side effects, they are typically only used against gram negative bacteria which have become resistant to other therapeutics. one family of aminoglycosides includes such compounds as butirosin, ribostamycin, neomycin, and kanamycin, amongst others. the common theme in these antibiotics is that they are constructed around a chemically stable aminocyclitol un ...201728685903
synthesis and characterization of novel astragalin galactosides using β-galactosidase from bacillus circulans.astragalin (kaempferol-3-o-β-d-glucopyranoside, ast) is a kind of flavonoid known to have anti-oxidant, anti-hiv, anti-allergic, and anti-inflammatory effects. it has low solubility in water. in this study, novel astragalin galactosides (ast-gals) were synthesized using β-galactosidase from bacillus circulans and reaction conditions were optimized to increase the conversion yield of astragallin. purified ast-gal1 (11.6% of ast used, w/w) and ast-gal2 (6.7% of ast used, w/w) were obtained by medi ...201728554386
biochemical characterization of the functional roles of residues in the active site of the β-galactosidase from bacillus circulans atcc 31382.the β-galactosidase enzyme from bacillus circulans atcc 31382 bgad is widely used in the food industry to produce prebiotic galactooligosaccharides (gos). recently, the crystal structure of a c-terminally truncated version of the enzyme (bgad-d) has been elucidated. the roles of active site amino acid residues in β-galactosidase enzyme reaction and product specificity have remained unknown. on the basis of a structural alignment of the β-galactosidase enzymes bgad-d from b. circulans and bgaa fr ...201728538097
complete genome sequence of the bacterium bacillus circulans jordan strain 32352.here, we report the complete genome sequence for the bacillus circulans jordan strain 32352. this species is a soil dwelling bacterium that expresses glycosyl hydrolase enzymes degrading pneumococcal capsular polysaccharides.201728495770
a chitin film containing basic fibroblast growth factor with a chitin-binding domain as wound dressings.basic fibroblast growth factor (bfgf) can stimulate wound healing. however, consistent delivery of bfgf has many disadvantages. to decrease their instability and diffusible, we introduced chitin-binding domain (chtbd) into bfgf. two expression plasimids were constructed. the first one (named bfgf) contained bfgf (154 amino acids), the second (named chtbd-bfgf) contained bfgf and the chtbd (54 amino acids). chtbd was derived from chitinase a1 (chia1) of bacillus circulans wl-12. the recombinant p ...201728821125
an atypical interaction explains the high-affinity of a non-hydrolyzable s-linked 1,6-α-mannanase inhibitor.the non-hydrolyzable s-linked azasugars, 1,6-α-mannosylthio- and 1,6-α-mannobiosylthioisofagomine, were synthesized and shown to bind with high affinity to a family 76 endo-1,6-α-mannanase from bacillus circulans. x-ray crystallography showed an atypical interaction of the isofagomine nitrogen with the catalytic acid/base. molecular dynamics simulations reveal that the atypical binding results from sulfur perturbing the most stable form away from the nucleophile interaction preferred for the o-l ...201728766587
construction and functional characterization of truncated versions of recombinant keratanase ii from bacillus circulans.there is a need for degradative enzymes in the study of glycosaminoglycans. many of these enzymes are currently available either in their natural or recombinant forms. unfortunately, progress in structure-activity studies of keratan sulfate (ks) have been impeded by the lack of a commercially available endo-β-n-acetylglucosaminidase, keratantase ii. the current study uses a recently published sequence of a highly thermostable keratanase ii identified in bacillus circulans to clone and express a ...201728752383
secretory expression of β-mannanase from bacillus circulans nt 6.7 in lactobacillus plantarum.the β-mannanase gene of bacillus circulans nt 6.7 was successfully cloned in lactobacillus plantarum wcfs1 using the psip403 expression vector and secreted to the supernatant rather than accumulated in the cells. the highest activity was achieved by controlling the ph at 6 during cultivation. maximum mannanase activities detected in the supernatant and cell-free extract of 200 ml mrs broth were 8.2 and 0.86 u/ml, respectively. enzyme activity in the supernatant increased to 27 u/ml by fermentati ...201728712957
biosurfactant production from pseudomonas taiwanensis l1011 and its application in accelerating the chemical and biological decolorization of azo dyes.dye dispersion and the interaction efficiency between azoreductases and dye molecules are rate-limiting steps for the decolorization of azo dyes. in this study, a biosurfactant-producing strain, pseudomonas taiwanensis l1011, was isolated from crude oil. to increase the yield of the biosurfactant bs-l1011 from p. taiwanensis l1011, culture conditions were optimized including temperature, initial ph, carbon source, nitrogen source and c/n ratio. a maximum yield of 1.12g/l of bs-l1011 was obtained ...201728689070
fusion of a family 20 carbohydrate-binding module (cbm20) with cyclodextrin glycosyltransferase of geobacillus sp. chb1 improves catalytic efficiency.cyclodextrin glycosyltransferase (cgtase) is an important industrial enzyme for production of cyclodextrins (cds) from starch by intramolecular transglycosylation. cgtase consists of five domains labeled a to e. for optimizing catalytic activity of cgtase, cgtase of geobacillus sp. was fused with the family 20 carbohydrate-binding module (cbm) of the bacillus circulans strain 251 cgtase. the cbmbc251 that has a low binding free energy with maltohexaose, was selected by in silico design. then the ...201728422446
an efficient process for obtaining prebiotic oligosaccharides derived from lactulose using isomerized and purified whey permeate.one of the most promising uses of whey permeate (wp) is the synthesis of prebiotic oligosaccharides. herein, commercial wp was submitted to chemical isomerization catalysed by sodium borate at an alkaline ph and subsequent purification using anion-exchange resins to remove boron. subsequently, purified mixtures were used to synthesize prebiotic oligosaccharides using β-galactosidase from bacillus circulans.201728417455
α-1,3-glucanase: present situation and prospect of research.α-1,3-glucanases hydrolyze α-1,3-glucan which is an insoluble linear α-1,3-linked homopolymer of glucose and these enzymes are classified into two families of glycoside hydrolases on the basis of amino acid sequence similarity; type-71 α-1,3-glucanases found in fungi and type-87 enzymes in bacteria. α-1,3-glucan (also called 'mutan') is a major component of dental plaque formed by oral streptococci and has important physiological roles in various fungal species, including as a component of cell ...201626748807
rationalising pka shifts in bacillus circulans xylanase with computational studies.bacillus circulans xylanase (bcx), a family 11 glycoside hydrolase, catalyses the hydrolysis of xylose polymers with a net retention of stereochemistry. glu172 in bcx is believed to act as a general acid by protonating the aglycone during glycosylation, and then as a general base to facilitate the deglycosylation step. the key to the dual role of this general acid/base lies in its protonation states, which depend on its intrinsic pka value and the specific environment which it resides within. to ...201627485091
a novel chemoenzymatic synthesis of sulfated type 2 tumor-associated carbohydrate antigens by transglycosylation of sulfated lewis x oxazoline catalyzed by keratanase ii.sulfated type 2 carbohydrate chains are known tumor-associated carbohydrate antigens (tacas). many reports on cancer vaccines employing tacas as specific antigens have been published, but structurally specified sulfated tacas have not been used because of the low natural abundance and difficulties in chemical synthesis. we demonstrate for the first time the synthesis of the sulfated type 2 tacas with an l-fucose branch by keratanase-ii-catalyzed transglycosylation of the sulfated lewis x (galβ(1 ...201627400395
comparative structural characterization of 7 commercial galacto-oligosaccharide (gos) products.many β-galactosidase enzymes convert lactose into a mixture of galacto-oligosaccharides (gos) when incubated under the right conditions. recently, the composition of commercial vivinal gos produced by bacillus circulans β-galactosidase was studied in much detail in another study by van leeuwen et al. as a spin-off of this study, we used the developed analytical strategy for the evaluation of 6 anonymous commercial gos products, in comparison with vivinal gos. these gos products were first subjec ...201627035911
bacillus oryzisoli sp. nov., isolated from rice rhizosphere.the taxonomy of strain 1ds3-10t, a gram-staining-positive, endospore-forming bacterium isolated from rice rhizosphere, was investigated using a polyphasic approach. phylogenetic analysis based on 16s rrna gene sequences demonstrated that the novel strain was grouped with established members of the genus bacillus and appeared to be closely related to the type strains bacillus benzoevorans dsm 5391t (97.9 %), bacillus circulans dsm 11t (97.7 %), bacillus novalis jcm 21709t (97.3 %), bacillus soli ...201627265352
thermostable β-galactosidases for the synthesis of human milk oligosaccharides.human milk oligosaccharides (hmos) designate a unique family of bioactive lactose-based molecules present in human breast milk. using lactose as a cheap donor, some β-galactosidases (ec 3.2.1.23) can catalyze transgalactosylation to form the human milk oligosaccharide lacto-n-neotetraose (lnnt; gal-β(1,4)-glcnac-β(1,3)-gal-β(1,4)-glc). in order to reduce reaction times and be able to work at temperatures, which are less welcoming to microbial growth, the current study investigates the possibilit ...201626802542
de novo biosynthesis of β-valienamine in engineered streptomyces hygroscopicus 5008.the c7n aminocyclitol β-valienamine is a lead compound for the development of new biologically active β-glycosidase inhibitors as chemical chaperone therapeutic agents for lysosomal storage diseases. its chemical synthesis is challenging due to the presence of multichiral centers in the structure. herein, we took advantage of a heterogeneous aminotransferase with stereospecificity and designed a novel pathway for producing β-valienamine in streptomyces hygroscopicus 5008, a validamycin producer. ...201626436873
detergent-compatible, organic solvent-tolerant alkaline protease from bacillus circulans mtcc 7942: purification and characterization.proteases are now recognized as the most indispensable industrial biocatalyst owing to their diverse microbial sources and innovative applications. in the present investigation, a thermostable, organic solvent-tolerant, alkaline serine protease from bacillus circulans mtcc 7942, was purified and characterized. the protease was purified to 37-fold by a three-step purification scheme with 39% recovery. the optimum ph and temperature for protease was 10 and 60 °c, respectively. the apparent molecul ...201625356983
larvicidal activity of bacillus circulans against the gastrointestinal nematode haemonchus contortus in sheep.efficient control of gastrointestinal parasites is necessary in sheep breeding. however, the available chemically based anthelmintics are becoming less effective due to the development of parasite resistance. an alternative to this problem is biological control. in the present study, we tested the larvicidal effect of bacillus circulans by administering a spore suspension (2 × 109 colony forming units/ml) orally to lambs naturally infected with haemonchus contortus. the number of faecal larvae w ...201626693886
asp577 mutations enhance the catalytic efficiency of cyclodextrin glycosyltransferase from bacillus circulans.the amino acid residue asp 577 is located in calcium-binding site iii (caiii) of the cyclodextrin glycosyltransferase (ec 2.4.1.19, cgtase) from bacillus circulans stb01. in the present study, the effects of replacing asp577 with glycine, alanine, valine, leucine, and isoleucine on the catalytic efficiency of this cgtase were investigated. two of these replacements, d577g and d577a, increased the β-cyclization activity of cgtase. kinetic studies showed that the km values of d577g and d577a were ...201626608005
bacillus circulans exopolysaccharide: production, characterization and bioactivities.a bacterium with the ability to produce appreciable amount of exopolysaccharide was isolated from slimy layer of coconut. 16s rdna analysis identified the organism as bacillus circulans. eps production was observed at all stages of culture growth and reached maximum of 0.065mg/ml by 96h, which on further incubation started to decrease. response surface methodology using box behnken design has shown the influence of sucrose which was found to be directly proportional to exopolysaccharide producti ...201626902891
a hybrid strategy using global analysis of oxidized fatty acids and bioconversion by bacillus circulans.targeted oxidized fatty acid analysis has been widely used to understand the roles of fatty acids in the development of diseases. however, because of the extensive structural diversity of fatty acids, it is considered that unknown lipid metabolites will remain undetected. here, to discover and identify unknown lipid metabolites in biological samples, a global analytical system and a method of synthesizing lipid standards were investigated.201626864527
association of bacillus circulans with non-diabetic foot infection in bangladeshi patient. 201526470981
characterization of mannanase from bacillus circulans nt 6.7 and its application in mannooligosaccharides preparation as prebiotic.this study focused on the characterization of mannanase from bacillus circulans nt 6.7 for mannooligosaccharides (mos) production. the enzyme from b. circulans nt 6.7 was produced using defatted copra meal as a carbon source. the mannanase was purified by ultrafiltration and column chromatography of q-sepharose. the purified protein (m1) was a dimeric protein with a 40 kda subunit. the purified m1 exhibited optimum ph and temperature at ph 6.0 and 60 °c, respectively. it was activated by mn(2+,) ...201526697281
molecular docking and site-directed mutagenesis of a bacillus thuringiensis chitinase to improve chitinolytic, synergistic lepidopteran-larvicidal and nematicidal activities.bacterial chitinases are useful in the biocontrol of agriculturally important pests and fungal pathogens. however, the utility of naturally occurring bacterial chitinases is often limited by their low enzyme activity. in this study, we constructed mutants of a bacillus thuringiensis chitinase with enhanced activity based on homology modeling, molecular docking, and the site-directed mutagenesis of target residues to modify spatial positions, steric hindrances, or hydrophilicity/hydrophobicity. w ...201525678849
purification and characterization of organic solvent stable serine alkaline protease from newly isolated bacillus circulans m34.a protease from newly isolated bacillus circulans m34 was purified by q-sepharose anion exchange chromatography and sepharose-bacitracin affinity chromatography followed by (nh4)2so4 precipitation. the molecular mass of the purified enzyme was determined using sds-page. the optimum ph and temperature for protease activity were 11 and 50°c, respectively. the effect of various metal ions on protease activity was investigated. alkaline protease from bacillus circulans m34 wase activated by zn(2+), ...201525677873
continuous production of cyclodextrins in an ultrafiltration membrane reactor, catalyzed by cyclodextrin glycosyltransferase from bacillus circulans df 9r.cyclodextrins (cds) are cyclic oligosaccharides of wide industrial application, whose synthesis is catalyzed by cyclodextrin glycosyltransferase (cgtase) from starch. here, cds were produced using cgtase from bacillus circulans df 9r in continuous process and an ultrafiltration membrane reactor. the batch process was conducted as a control. this method allowed increasing the yield from 40 to 55.6% and the productivity from 26.1 to 99.5 mg of cd per unit of enzyme. the method also allowed obtaini ...201525583301
bacillus species isolated from tungrymbai and bekang, naturally fermented soybean foods of india.tungrymbai and bekang are naturally fermented soybean foods commonly consumed in meghalaya and mizoram states of india. a total of 39 samples of tungrymbai and 43 samples of bekang were collected from different villages and markets of meghalaya and mizoram, respectively and were analysed for microbial load. in both tungrymbai and bekang, the average population of bacillus spp. was 8.2±0.1 log cfu/g. a total of 428 isolates of bacillus were isolated from tungrymbai (211) and bekang (217) for deta ...201525574846
cyclodextrin glycosyltransferase production by free cells of bacillus circulans df 9r in batch fermentation and by immobilized cells in a semi-continuous process.cyclodextrin glycosyltransferase (cgtase) catalyzes starch conversion into cyclic or linear oligosaccharides, important industrial products for the complexation of non-polar substances. in this work, conditions to increase cgtase production from bacillus circulans strain df 9r were optimized by two systems. on one hand, free cells were grown in batch fermentation experiments to optimize aeration and ph. the highest activity (1.47 ± 0.21 u ml(-1)) was achieved after 48 h of growth, aeration of 1. ...201525561345
monobody-mediated alteration of enzyme specificity.current methods for engineering enzymes modify enzymes themselves and require a detailed mechanistic understanding or a high-throughput assay. here, we describe a new approach where catalytic properties are modulated with synthetic binding proteins, termed monobodies, directed to an unmodified enzyme. using the example of a β-galactosidase from bacillus circulans, we efficiently identified monobodies that restricted its substrates for its transgalactosylation reaction and selectively enhanced th ...201526322825
characterization of deep sea fish gut bacteria with antagonistic potential, from centroscyllium fabricii (deep sea shark).the bacterial isolates from centroscyllium fabricii (deep sea shark) gut were screened for antagonistic activity by cross-streak method and disc diffusion assay. this study focuses on strain btss-3, which showed antimicrobial activity against pathogenic bacteria including salmonella typhimurium, proteus vulgaris, clostridium perfringens, staphylococcus aureus, bacillus cereus, bacillus circulans, bacillus macerans and bacillus pumilus. btss3 was subjected to phenotypic characterization using bio ...201525740801
recombinant, truncated b. circulans keratanase-ii: description and characterisation of a novel enzyme for use in measuring urinary keratan sulphate levels via lc-ms/ms in morquio a syndrome.morquio a syndrome (mucopolysaccharidosis iva; mps iva) is an autosomal recessive lysosomal storage disorder caused by deficient n-acetylgalactosamine-6-sulphatase (galns) activity. early and accurate diagnosis of this condition is critical for improved patient outcomes, particularly as enzyme replacement therapy has recently become available. an lc-ms/ms assay utilising keratan sulphate (ks) disaccharides derived from keratanase-ii digestion provides a sensitive and specific means for quantitat ...201525866399
mutations at calcium binding site iii in cyclodextrin glycosyltransferase improve β-cyclodextrin specificity.cyclodextrin glycosyltransferases (cgtases, ec 2.4.1.19) are industrially important enzymes that produce cyclodextrins from starch by intramolecular transglycosylation. in this study, the effects of amino acid residue at position 315 in calcium binding site iii (caiii) on product specificity of cgtase were investigated by replacing ala315 in the cgtase from bacillus circulans stb01 with arginine, aspartic acid, threonine, leucine and valine. the cgt gene, which encodes this enzyme, was expressed ...201525748847
epimerization at c-3'' in butirosin biosynthesis by an nad(+) -dependent dehydrogenase btre and an nadph-dependent reductase btrf.butirosin is an aminoglycoside antibiotic consisting two epimers at c-3'' of ribostamycin/xylostasin with a unique 4-amino-2-hydroxybutyrate moiety at c-1 of the aminocyclitol 2-deoxystreptamine (2dos). to date, most of the enzymes encoded in the biosynthetic gene cluster for butirosin, from the producing strain bacillus circulans, have been characterized. a few unknown functional proteins, including nicotinamide adenine dinucleotide cofactor-dependent dehydrogenase/reductase (btre and btrf), ar ...201525600434
transgalactosylation and hydrolytic activities of commercial preparations of β-galactosidase for the synthesis of prebiotic carbohydrates.β-galactosidases exhibit both hydrolytic and transgalactosylation activities; the former has been used traditionally for the production of delactosed milk and dairies, while the latter is being increasingly used for the synthesis of lactose-derived oligosaccharides: balance between both activities was highly dependent on the enzyme origin: β-galactosidases from aspegillus oryzae and bacillus circulans exhibited high transgalactosylation activity, while those from one from kluyveromyces exhibited ...201525659627
molecular engineering of cycloisomaltooligosaccharide glucanotransferase from bacillus circulans t-3040: structural determinants for the reaction product size and reactivity.cycloisomaltooligosaccharide glucanotransferase (citase) is a member of glycoside hydrolase family 66 and it produces cycloisomaltooligosaccharides (cis). small cis (ci-7-9) and large cis (ci-≥10) are designated as oligosaccharide-type cis (oligo-cis) and megalosaccharide-type cis (megalo-cis) respectively. citase from bacillus circulans t-3040 (bccitase) produces mainly ci-8 with little megalo-cis. it has two family 35 carbohydrate-binding modules (bccbm35-1 and bccbm35-2). bccbm35-1 is inserte ...201525649478
relationship between sol-gel conditions and enzyme stability: a case study with β-galactosidase/silica biocatalyst for whey hydrolysis.the sol-gel process has been very useful for preparing active and stable biocatalysts, with the possibility of being reused. especially those based on silica are well known. however, the study of the enzyme behavior during this process is not well understood until now and more, if the surfactant is involved in the synthesis mixture. this work is devoted to the encapsulation of β-galactosidase from bacillus circulans in silica by sol-gel process, assisted by non-ionic triton x-100 surfactant. the ...201526313518
crystal structure of β-galactosidase from bacillus circulans atcc 31382 (bgad) and the construction of the thermophilic mutants.β-galactosidase (ec 3.2.1.23) from bacillus circulans atcc 31382, designated bgad, exhibits high transglycosylation activity to produce galacto-oligosaccharides. bgad has been speculated to have a multiple domain architecture including a f5/8-type c domain or a discoidin domain in the c-terminal peptide region from amino acid sequence analysis. here, we solved the first crystal structure of the c-terminal deletion mutant bgad-d, consisting of sugar binding, glyco_hydro, catalytic and bacterial i ...201525879162
efficiency of plant growth-promoting p-solubilizing bacillus circulans cb7 for enhancement of tomato growth under net house conditions.p-solubilizing bacterial isolate cb7 isolated from apple rhizosphere soil of himachal pradesh, india was identified as bacillus circulans on the basis of phenotypic characteristics, biochemical tests, fatty acid methyl esters analysis, and 16s rrna gene sequence. the isolate exhibited plant growth-promoting traits of p-solubilization, auxin, 1-aminocyclopropane-1-carboxylate deaminase activity, siderophore, nitrogenase activity, and antagonistic activity against dematophora necatrix. in vitro st ...201524464353
[anchorage of cyclodextrin glycosyltransferase on outer membrane of saccharomyces cerevisiae to produce 2-o-α-d-glucopyranosyl-l-ascorbic acid].displaying cyclodextrin glycosyltransferase ( cgtase) from bacillus circulans 251 on the cell surface of saccharomyces cerevisiae to improve 2-o-α-d-glucopyranosyl-l-ascorbic acid (aa-2g) production.201526939459
evidence for cycloisomaltooligosaccharide production from starch by bacillus circulans t-3040.bacillus circulans t-3040 produces cycloisomaltooligosaccharide glucanotransferase (citase) and cycloisomaltooligosaccharides (cyclodextrans, cis) when it is grown in media containing dextran as the carbon source. to investigate the effects of carbon sources on citase activity, b. circulans t-3040 was cultured with glucose; sucrose; a mixture of isomaltose, isomaltotriose, and panose (imos); a mixture of maltohexaose and maltoheptaose (g67); dextrin (average degree of polymerization = 36); dextr ...201424463763
structural basis of a mutant y195i α-cyclodextrin glycosyltransferase with switched product specificity from α-cyclodextrin to β-/γ-cyclodextrin.cyclodextrin glycosyltransferase (ec 2.4.1.19) (cgtase) is an extracellular bacterial enzyme which has the unique capability of forming cyclodextrins from starch. our previous investigation revealed that a mutant y195i α-cgtase drastically altered the cyclodextrin specificity by switching toward the synthesis of both β- and γ-cds (xie et al., 2013a,b). in this study, we determined one x-ray structure of the mutant y195i α-cgtase at 2.3å. the overall structure was similar to that of the typical β ...201424637377
detection and characterization of serine and threonine hydroxyl protons in bacillus circulans xylanase by nmr spectroscopy.hydroxyl protons on serine and threonine residues are not well characterized in protein structures determined by both nmr spectroscopy and x-ray crystallography. in the case of nmr spectroscopy, this is in large part because hydroxyl proton signals are usually hidden under crowded regions of (1)h-nmr spectra and remain undetected by conventional heteronuclear correlation approaches that rely on strong one-bond (1)h-(15)n or (1)h-(13)c couplings. however, by filtering against protons directly bon ...201424306180
polyethylene glycols enhance the thermostability of β-cyclodextrin glycosyltransferase from bacillus circulans.we investigated the ability of six polyethylene glycols (pegs), with molecular weights ranging from 400 to 20,000 da, to enhance the thermostability of β-cyclodextrin glycosyltransferase (β-cgtase) from bacillus circulans. we found that pegs with different molecular weights could activate and stabilize this β-cgtase, but to different degrees. the most significant increase (about 20%) in β-cyclodextrin-forming activity was achieved by adding 10-15% peg 400. pegs with low molecular weights also si ...201424996299
enhancing the activity of bacillus circulans xylanase by modulating the flexibility of the hinge region.enzymes undergo multiple conformational changes in solution, and these dynamics are considered to play a critical role in enzyme activity. hinge-bending motions, resulting from reciprocal movements of dynamical quasi-rigid bodies, are thought to be related to turnover rate and are affected by the physical properties of the hinge regions. in this study, hinge identification and flexibility modification of the regions by mutagenesis were conducted to explore the relationship between hinge flexibil ...201424849049
mutations enhance β-cyclodextrin specificity of cyclodextrin glycosyltransferase from bacillus circulans.the effects of amino acid residue at position 31 in the neighborhood of calcium binding site i (cai) on product specificity of cyclodextrin glycosyltransferase (ec 2.4.1.19, cgtase) were investigated by replacing ala31 in the cgtase from bacillus circulans stb01 with arginine, proline, threonine, serine and glycine. the results showed that the mutations a31r, a31p, and a31t resulted in the increases in β-cyclodextrin-forming activity and β-cyclodextrin production, indicating that these mutations ...201424751254
nanosilica sol leads to further increase in polyethylene glycol (peg) 1000-enhanced thermostability of β-cyclodextrin glycosyltransferase from bacillus circulans.a major disadvantage of cyclodextrin production is the limited thermostability of cyclodextrin glycosyltransferase. the ability of combinations of nanosilica sol with polyethylene glycol (peg) 1000 to enhance the thermostability of the β-cyclodextrin glycosyltransferase from bacillus circulans was investigated. it was found that 10% peg 1000 combined with 0.05% nanosilica sol could activate the β-cyclodextrin glycosyltransferase by 17.2%. furthermore, 0.05% nanosilica sol leads to further increa ...201424641510
lna-modified isothermal oligonucleotide microarray for differentiating bacilli of similar origin.oligonucleotide microarray has been one of the most powerful tools in the 'post-genome era' for its high sensitivity, high throughput and parallel processing capability. to achieve high detection specificity, we fabricated an isothermal microarray using locked nucleic acid (lna)-modified oligonucleotide probes, since lna has demonstrated the advanced ability to enhance the binding affinity toward their complementary nucleotides. after designing the nucleotide sequences of these oligonucleotide p ...201425431409
production of potent antimicrobial agent by actinomycete, streptomyces sannanensis strain su118 isolated from phoomdi in loktak lake of manipur, india.actinomycetes have provided a wealth of bioactive secondary metabolites with interesting activities such as antimicrobial, antiviral and anticancer. the study aims at isolation, characterization and the antimicrobial potentiality of streptomyces sannanensis su118 obtained from phoomdi, a unique habitat of loktak lake of manipur, india.201425406714
bacillus mesophilum sp. nov., strain iitr-54t, a novel 4-chlorobiphenyl dechlorinating bacterium.the taxonomic position of a gram-positive, endospore-forming bacterium isolated from soil sample collected from an industrial site was analyzed by a polyphasic approach. the strain designated as iitr-54t matched most of the phenotypic and chemical characteristics of the genus bacillus and represents a novel species. it was found to biodegrade 4-chlorobiphenyl through dechlorination and was isolated through enrichment procedure from an aged polychlorinated biphenyl-contaminated soil. both resting ...201424807729
biochemical characterization of mutants in the active site residues of the β-galactosidase enzyme of bacillus circulans atcc 31382.the bacillus circulans atcc 31382 β-galactosidase (bgad) is a retaining-type glycosidase of glycoside hydrolase family 2 (gh2). its commercial enzyme preparation, biolacta n5, is used for commercial-scale production of galacto-oligosaccharides (gos). the bgad active site and catalytic amino acid residues have not been studied. using bioinformatic routines we identified two putative catalytic glutamates and two highly conserved active site histidines. the site-directed mutants e447n, e532q, and h ...201425473598
(1)h nmr analysis of the lactose/β-galactosidase-derived galacto-oligosaccharide components of vivinal® gos up to dp5.vivinal® gos is a galacto-oligosaccharide (gos) product, prepared from lactose by incubation with bacillus circulans β-galactosidase (ec 3.2.1.23). this complex mixture of saccharides with degree of polymerization (dp) between 1 and 8 is generally applied in infant nutrition. here, a detailed structural description of the commercial product up to the dp5 level is given. first, vivinal® gos was subjected to dp analysis using hplc-sec (rezex rso-01 oligosaccharide ag(+) column) and (1)h nmr analys ...201425444767
characterization of a galactosynthase derived from bacillus circulans β-galactosidase: facile synthesis of d-lacto- and d-galacto-n-bioside.glycosynthases-retaining glycosidases mutated at their catalytic nucleophile-catalyze the formation of glycosidic bonds from glycosyl fluorides as donor sugars and various glycosides as acceptor sugars. here the first glycosynthase derived from a family 35 β-galactosidase is described. the glu→gly mutant of bgac from bacillus circulans (bgac-e233g) catalyzed regioselective galactosylation at the 3-position of the sugar acceptors with α-galactosyl fluoride as the donor. transfer to 4-nitophenyl α ...201424458919
biochemical, structural, and genetic characterization of tridecaptin a₁, an antagonist of campylobacter jejuni.bacillus circulans nrrl b-30644 (now paenibacillus terrae) was previously reported to produce srcam 1580, a bacteriocin active against the food pathogen campylobacter jejuni. we have been unable to isolate srcam 1580, and did not find any genetic determinants in the genome of this strain. we now report the reassignment of this activity to the lipopeptide tridecaptin a₁. structural characterization of tridecaptin a1 was achieved through nmr, ms/ms and gc-ms studies. the structure was confirmed th ...201424382692
mutations in cyclodextrin glycosyltransferase from bacillus circulans enhance β-cyclization activity and β-cyclodextrin production.cyclodextrin glycosyltransferase (ec 2.4.1.19, cgtase) is used to produce cyclodextrins, which are cyclic glucans with many industrial applications. in the present study, the effects of the amino acid residue at position 577, which is located in calcium-binding site iii (caiii), on cyclization activity and cyclodextrin production were investigated by replacing asp577 in cgtase from bacillus circulans stb01 with glutamate, arginine, lysine, and histidine. the results showed that mutations d577e a ...201425359453
improvement of chitosan derivatization for the immobilization of bacillus circulans β-galactosidase and its further application in galacto-oligosaccharide synthesis.chitosan was derivatized by two methodologies to design a robust biocatalyst of immobilized bacillus circulans β-galactosidase from a low-cost support for its further application in the synthesis of galacto-oligosaccharides (gos). in the first one, chitosan was derivatized by cross-linking with glutaraldehyde and activated with epichlorohydrin; in the second one, cross-linking and activation were done with epichlorohydrin in a two-step process, favoring first support cross-linking and then suppo ...201425188813
cloning, secretory expression and characterization of recombinant β-mannanase from bacillus circulans nt 6.7.the mannanase gene of b. circulans nt 6.7 was cloned and expressed in an escherichia coli expression system. the b. circulans nt 6.7 mannanase gene consists of 1,083 nucleotides encoding a 360-amino acid residue long polypeptide, belonging to glycoside hydrolase family 26. the full-length mannanase gene including its native signal sequence was cloned into the vector pet21d and expressed in e. coli bl21 (de3). β-mannanase activities in the culture supernatant and crude cell extract were 37.10 and ...201425157333
characterization of a lichenase isolated from soil metagenome.a lichenase gene (mt-lic) was identified for the first time through function-based screening of a soil metagenomic library. its deduced amino acid sequence exhibited a high degree of homology with endo-β-1,3-1,4-glucanase (having both lichenase and chitosanase activities), encoded by the bgc gene of bacillus circulans wl-12. the recombinant lichenase overexpressed and purified from escherichia coli was able to efficiently hydrolyze both barley β-glucan and lichenan. the enzyme showed maximal act ...201425152058
development of hypoallergenic galacto-oligosaccharides on the basis of allergen analysis.galacto-oligosaccharides (goss) are recognized as prebiotics beneficial to human health through their abilities to modulate gut microbiota. on the other hand, it has been reported that immediate allergic reactions are caused by a gos product (bc-gos) produced by treating lactose with β-galactosidase derived from bacillus circulans. the objective of this study was to create a safer gos product that is less likely to cause gos-induced allergy (gos-al). first, we identified two derivatives of tetra ...201425036491
rational design of a glycosynthase by the crystal structure of β-galactosidase from bacillus circulans (bgac) and its use for the synthesis of n-acetyllactosamine type 1 glycan structures.the crystal structure of β-galactosidase from bacillus circulans (bgac) was determined at 1.8å resolution. the overall structure of bgac consists of three distinct domains, which are the catalytic domain with a tim-barrel structure and two all-β domains (abds). the main-chain fold and steric configurations of the acidic and aromatic residues at the active site were very similar to those of streptococcus pneumoniae β(1,3)-galactosidase bgac in complex with galactose. the structure of bgac was use ...201425034434
structural elucidation of the cyclization mechanism of α-1,6-glucan by bacillus circulans t-3040 cycloisomaltooligosaccharide glucanotransferase.bacillus circulans t-3040 cycloisomaltooligosaccharide glucanotransferase belongs to the glycoside hydrolase family 66 and catalyzes an intramolecular transglucosylation reaction that produces cycloisomaltooligosaccharides from dextran. the crystal structure of the core fragment from ser-39 to met-738 of b. circulans t-3040 cycloisomaltooligosaccharide glucanotransferase, devoid of its n-terminal signal peptide and c-terminal nonconserved regions, was determined. the structural model contained o ...201424616103
cgtase-catalysed cis-glucosylation of l-rhamnosides for the preparation of shigella flexneri 2a and 3a haptens.we report the enzymatic synthesis of α-d-glucopyranosyl-(1→4)-α-l-rhamnopyranoside and α-d-glucopyranosyl-(1→3)-α-l-rhamnopyranoside by using a wild-type transglucosidase in combination with glucoamylase and glucose oxidase. it was shown that bacillus circulans 251 cyclodextrin glucanotransferase (cgtase, ec 2.1.4.19) can efficiently couple an α-l-rhamnosyl acceptor to a maltodextrin molecule with an α-(1→4) linkage, albeit in mixture with the α-(1→3) regioisomer, thus giving two glucosylated ac ...201424376024
galactooligosaccharides formation during enzymatic hydrolysis of lactose: towards a prebiotic-enriched milk.the formation of galactooligosaccharides (gos) in skim milk during treatment with several commercial β-galactosidases (bacillus circulans, kluyveromyces lactis and aspergillus oryzae) was analysed in detail, at 4 and 40°c. the maximum gos concentration was obtained at a lactose conversion of approximately 40-50% with b. circulans and a. oryzae β-galactosidases, and at 95% lactose depletion for k. lactis β-galactosidase. using an enzyme dosage of 0.1% (v/v), the maximum gos concentration with k. ...201424128493
kinetic characterization of galacto-oligosaccharide (gos) synthesis by three commercially important β-galactosidases.many β-galactosidases show large differences in galacto-oligosaccharide (gos) production and lactose hydrolysis. in this study, a kinetic model is developed in which the effect of lactose, glucose, galactose, and oligosaccharides on the onpg converting activity of various β-galactosidases is quantified. the use of onpg as a competing substrate to lactose yields more information than can be obtained by examining only the conversion of lactose itself. the reaction rate with lactose or oligosacchar ...201424124064
does a rhizospheric microorganism enhance k⁺ availability in agricultural soils?the potassium solubilizing microorganisms (ksms) are a rhizospheric microorganism which solubilizes the insoluble potassium (k) to soluble forms of k for plant growth and yield. k-solubilization is carried out by a large number of saprophytic bacteria (bacillus mucilaginosus, bacillus edaphicus, bacillus circulans, acidothiobacillus ferrooxidans, paenibacillus spp.) and fungal strains (aspergillus spp. and aspergillus terreus). major amounts of k containing minerals (muscovite, orthoclase, bioti ...201424315210
comparative study of the fungicide benomyl toxicity on some plant growth promoting bacteria and some fungi in pure cultures.six laboratory experiments were carried out to investigate the effect of the fungicide benomyl on pure cultures of some plant growth promoting bacteria (pgpb) and some fungi. the highest ld50 was recorded for bacillus circulans and proved to be the most resistant to the fungicide, followed by azospirillum braziliense, while penicillium sp. was the most affected microorganism. ld50 values for the affected microorganisms were in 21-240 orders of magnitude lower in comparison with the ld50 value fo ...201426038670
biodiversity of aerobic endospore-forming bacterial species occurring in yanyanku and ikpiru, fermented seeds of hibiscus sabdariffa used to produce food condiments in benin.yanyanku and ikpiru made by the fermentation of malcavene bean (hibiscus sabdariffa) are used as functional additives for parkia biglobosa seed fermentations in benin. a total of 355 aerobic endospore-forming bacteria (aefb) isolated from yanyanku and ikpiru produced in northern and southern benin were identified using phenotypic and genotypic methods, including gtg5-pcr, m13-pcr, 16s rrna, gyra and gyrb gene sequencing. generally, the same 5-6 species of the genus bacillus predominated: bacillu ...201323571124
hierarchical meso-macroporous silica grafted with glyoxyl groups: opportunities for covalent immobilization of enzymes.hierarchical meso-macroporous silica (average mesopore diameter 20 nm) was synthesized and chemically modified to be used as a support for the immobilization of lipases from candida antarctica b and alcaligenes sp. and β-galactosidases from bacillus circulans and aspergillus oryzae. catalytic activities and thermal stabilities of enzymes immobilized by multipoint covalent attachment in silica derivatized with glyoxyl groups were compared with those immobilized in glyoxyl-agarose, assessing bioca ...201323416689
detailed analysis of galactooligosaccharides synthesis with β-galactosidase from aspergillus oryzae.the synthesis of galactooligosaccharides (gos) catalyzed by β-galactosidase from aspergillus oryzae (enzeco) was studied. using 400 g/l of lactose and 15 u/ml, maximum gos yield, measured by hpaec-pad, was 26.8% w/w of total carbohydrates, obtained at approximately 70% lactose conversion. no less than 17 carbohydrates were identified; the major transgalactosylation product was 6'-o-β-galactosyl-lactose, representing nearly one-third (in weight) of total gos. in contrast with previous reports, th ...201323330921
characterization of antifungal activity of the gh-46 subclass iii chitosanase from bacillus circulans mh-k1.we characterized the antifungal activity of the bacillus circulans subclass iii mh-k1 chitosanase (mh-k1 chitosanase), which is one of the most intensively studied glycoside hydrolases (ghs) that belong to gh family 46. mh-k1 chitosanase inhibited the growth of zygomycetes fungi, rhizopus and mucor, even at 10 pmol (0.3 μg)/ml culture probably via its fungistatic effect. the amino acid substitution e37q abolished the antifungal activity of mh-k1 chitosanase, but retained binding to chitotriose. ...201323892828
induction of resistance in tomato plants against tomato mosaic tobamovirus using beneficial microbial isolates.the possibility of making use of the phenome non of systemic acquired resistance (sar) to control viruses achieved by the soaking treatment of tomato seeds cv. castl rock with three growth forms to bacillus circulans, pseudomonas fluorescens 2 and trichoderma harzianum against tomato mosaic tobamovirus (tomv) infection. all the application forms of beneficial biotic inducers were reduced the mean number of tomv local lesions on datura metel. p. fluorescens 2 was found to be the best treatment in ...201324494520
production of alkaline protease by solvent-tolerant alkaliphilic bacillus circulans mtcc 7942 isolated from hydrocarbon contaminated habitat: process parameters optimization.in the present investigation, a newly isolated organic solvent-tolerant and alkaliphilic bacterial strain was reported from a hydrocarbon (gasoline and diesel) contaminated soil collected from the petrol station, shirpur (india). the strain was identified as bacillus circulans mtcc 7942, based on phenotype, biochemical, and phylogenetic analysis of 16s rrna gene sequence. the capability of bacillus circulans to secrete an extracellular, thermostable, alkaline protease and grow in the presence of ...201325937965
effects of carbohydrates on the onpg converting activity of β-galactosidases.the effects of high concentrations of carbohydrates on the o-nitrophenyl β-d-galactopyranoside (onpg) converting activity of β-galactosidase from bacillus circulans are studied to get a better understanding of the enzyme behavior in concentrated and complicated systems in which enzymatic synthesis of galacto-oligosaccharides is usually performed. the components that were tested were glucose, galactose, lactose, sucrose, trehalose, raffinose, vivinal gos, dextran-6000, dextran-70,000, and sarcosi ...201323725091
involvement of gln679, in addition to trp687, in chitin-binding activity of the chitin-binding domain of chitinase a1 from bacillus circulans wl-12.chitinase a1 (chia1) from bacillus circulans wl-12 comprises an n-terminal catalytic domain, two fibronectin type iii domains, and a c-terminal chitin-binding domain (chbd). the chbd of chia1 (chbdchia1) belongs to carbohydrate-binding module (cbm) family 12 and specifically binds to insoluble or crystalline chitin. it has been suggested that tryptophan-687 (trp687) is involved in the chitin-binding activity of this chbd. site-directed mutagenesis was used to identify additional amino acid resid ...201323694779
strategies for modulating the ph-dependent activity of a family 11 glycoside hydrolase.the ph-dependent activity of wild-type bacillus circulans xylanase (bcx) is set by the pk(a) values of its nucleophile glu78 and general acid/base glu172. herein, we examined several strategies to manipulate these pk(a) values and thereby shift the ph(opt) at which bcx is optimally active. altering the global charge of bcx through random succinylation had no significant effect. mutation of residues near or within the active site of bcx, but not directly contacting the catalytic carboxyls, either ...201323578322
characterization of β-galactosidase isoforms from bacillus circulans and their contribution to gos production.a β-galactosidase preparation from bacillus circulans consists of four isoforms called β-gal-a, β-gal-b, β-gal-c, and β-gal-d. these isoforms differ in lactose hydrolysis and galacto-oligosaccharide (gos) synthesis at low substrate concentrations. for this reason, using a selection of the isoforms may be relevant for gos production, which is typically done at high substrate concentrations. at initial lactose concentrations in between 0.44 % and 0.68 % (w/w), β-gal-a showed the least oligosacchar ...201323526073
β-galactosidase stability at high substrate concentrations.enzymatic synthesis of galacto-oligosaccharides is usually performed at high initial substrate concentrations since higher yields are obtained. we report here on the stability of β-galactosidase from bacillus circulans at 25, 40, and 60°c in buffer, and in systems with initially 5.0 and 30% (w/w) lactose. in buffer, the half-life time was 220 h and 13 h at 25 and 40°c, respectively, whereas the enzyme was completely inactivated after two hours at 60°c. in systems with 5.0 and 30% (w/w) lactose, ...201324024090
calcium ion contribution to thermostability of cyclodextrin glycosyltransferase is closely related to calcium-binding site caiii.in the study, we investigated the contribution of ca²⁺ to the thermostability of α-cyclodextrin glycosyltransferase (α-cgtase) from paenibacillus macerans , which has two calcium-binding sites (cai and caii), and β-cgtase from bacillus circulans , which contains an additional calcium-binding site (caiii), consisting of ala315 and asp577. it was found that the contribution of ca²⁺ to the thermostability of two cgtases displayed a marked difference. ca²⁺ affected β-cgtase thermostability significa ...201323968201
the discoidin domain of bacillus circulans β-galactosidase plays an essential role in repressing galactooligosaccharide production.the recently cloned β-galactosidase from bacillus circulans atcc 31382, designated bgad, contains a multiple domain architecture including a f5/8 type c domain or a discoidin (ds) domain in the c-terminal peptide region. here we report that the ds domain plays an essential role in repressing the production of galactooligosaccharides (goss). we prepared deletion mutants and point-mutated forms of rbgad-a (deletion of the bgad signal peptide) to compare their reaction behaviors. the yields of goss ...201323291776
recombinant production and characterization of full-length and truncated β-1,3-glucanase pgla from paenibacillus sp. s09.β-1,3-glucanases catalyze the hydrolysis of glucan polymers containing β-1,3-linkages. these enzymes are of great biotechnological, agricultural and industrial interest. the applications of β-1,3-glucanases is well established in fungal disease biocontrol, yeast extract production and wine extract clarification. thus, the identification and characterization of novel β-1,3-glucanases with high catalytic efficiency and stability is of particular interest.201324283345
x-ray analysis of butirosin biosynthetic enzyme btrn redefines structural motifs for adomet radical chemistry.the 2-deoxy-scyllo-inosamine (doia) dehydrogenases are key enzymes in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics. in contrast to most doia dehydrogenases, which are nad-dependent, the doia dehydrogenase from bacillus circulans (btrn) is an s-adenosyl-l-methionine (adomet) radical enzyme. to examine how btrn employs adomet radical chemistry, we have determined its structure with adomet and substrate to 1.56 å resolution. we find a previously undescribed modificat ...201324048029
domain structure and function of α-1,3-glucanase from bacillus circulans ka-304, an enzyme essential for degrading basidiomycete cell walls.bacillus circulans ka-304 α-1,3-glucanase (agl-ka) includes an n-terminal discoidin domain (ds1), a carbohydrate binding module family 6 (cb6), threonine and proline repeats (tps), a second discoidin domain (ds2), an uncharacterized conserved domain (ucd), and a c-terminal catalytic domain. domain deletion enzymes lacking ds1, cb6, and ds2 exhibited lower α-1,3-glucan-hydrolyzing and -binding activities than the wild type, agl-ka. an α-1,3-glucan binding assay with fluorescent protein fusion pro ...201323470772
immobilization of nisin producer lactococcus lactis strains to chitin with surface-displayed chitin-binding domain.in this study, nisin producer lactococcus lactis strains displaying cell surface chitin-binding domain (chbd) and capable of immobilizing to chitin flakes were constructed. to obtain chbd-based cell immobilization, usp45 signal sequence with chbd of chitinase a1 enzyme from bacillus circulans was fused with different lengths of prtp (153, 344, and 800 aa) or acma (242 aa) anchors derived from l. lactis. according to the whole cell elisa analysis, chbd was successfully expressed on the surface of ...201323354445
cloning and biochemical characterization of an endo-1,4-β-mannanase from the coffee berry borer hypothenemus hampei.the study of coffee polysaccharides-degrading enzymes from the coffee berry borer hypothenemus hampei, has become an important alternative in the identification for enzymatic inhibitors that can be used as an alternative control of this dangerous insect. we report the cloning, expression and biochemical characterization of a mannanase gene that was identified in the midgut of the coffee berry borer and is responsible for the degradation of the most abundant polysaccharide in the coffee bean.201323965285
synthesis of prebiotic carbohydrates derived from cheese whey permeate by a combined process of isomerisation and transgalactosylation.lactose from cheese whey permeate (wp) was efficiently isomerised to lactulose using egg shell, a food-grade catalyst, and the subsequent transgalactosylation reaction of this mixture with β-galactosidase from bacillus circulans gave rise to a wide array of prebiotic carbohydrates derived from lactose and lactulose.201323096763
crystallization and preliminary x-ray crystallographic analysis of cycloisomaltooligosaccharide glucanotransferase from bacillus circulans t-3040.bacillus circulans t-3040 cycloisomaltooligosaccharide glucanotransferase (bccitase) catalyses an intramolecular transglucosylation reaction and produces cycloisomaltooligosaccharides from dextran. bccitase was overexpressed in escherichia coli in two different forms and crystallized by the sitting-drop vapour-diffusion method. the crystal of bccitase bearing an n-terminal his₆ tag diffracted to a resolution of 2.3 å and belonged to space group p3₁21, containing a single molecule in the asymmetr ...201323908050
a computational method for the systematic screening of reaction barriers in enzymes: searching for bacillus circulans xylanase mutants with greater activity towards a synthetic substrate.we present a semi-empirical (pm6-based) computational method for systematically estimating the effect of all possible single mutants, within a certain radius of the active site, on the barrier height of an enzymatic reaction. the intent of this method is not a quantitative prediction of the barrier heights, but rather to identify promising mutants for further computational or experimental study. the method is applied to identify promising single and double mutants of bacillus circulans xylanase ...201323904990
differences in the roles of a glutamine amidotransferase subunit of pyridoxal 5'-phosphate synthase between bacillus circulans and bacillus subtilis.btrc2 of the butirosin producer bacillus circulans is a non-catalytic subunit of 2-deoxy-scyllo-inosose (doi) synthase that is involved in butirosin biosynthesis, and also a homolog of glutamine amidotransferase subunit (pdxt) of pyridoxal 5'-phosphate (plp) synthase of bacillus subtilis. btrc2 has been found to have functions in b. circulans both in primary and secondary metabolism. in this study, we investigated the properties of pdxt of b. subtilis in order to determine whether the property o ...201323832367
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