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thermal destabilization of rhizomucor miehei rennet with aldehyde dextran sulfate: purification, bioconjugation and milk-clotting activities.high thermal stability of rhizomucor miehei rennet, which is a thermostable enzyme used in cheese production, causes undesired cases at elevated temperatures. this study aims to decrease the thermal stability of the r. miehei rennet at high temperatures. to achieve this goal, bioconjugates of r. miehei rennet with aldehyde derivative of dextran sulfate were synthesized in different molar ratios. physico-chemical properties of bioconjugates were characterized with particle size analyzer and gel p ...201627138725
evaluation of the catalytic specificity, biochemical properties, and milk clotting abilities of an aspartic peptidase from rhizomucor miehei.in this study, we detail the specificity of an aspartic peptidase from rhizomucor miehei and evaluate the effects of this peptidase on clotting milk using the peptide sequence of k-casein (abz-lsfmaiq-eddnp) and milk powder. molecular mass of the peptidase was estimated at 37 kda, and optimum activity was achieved at ph 5.5 and 55 °c. the peptidase was stable at ph values ranging from 3 to 5 and temperatures of up 45 °c for 60 min. dramatic reductions in proteolytic activity were observed with e ...201627165660
[structure and activity of fungal lipases in bile salt solutions].the changes in structure and catalytic properties of fungal lipases (candida rugosa, rhizomucor miehei, mucor javanicus) were investigated in micellar solutions of bile salts that differ in hydrophilic-lypophilic balance and reaction medium properties. the methods of circular dichroism and tryptophan fluorescence were applied to estimate the changes in peptide structure within complexes with bile salt micelles. bile salts do not exert a significant influence on the structure of the enzymes under ...201627192825
reversible immobilization of lipases on heterofunctional octyl-amino agarose beads prevents enzyme desorption.two different heterofunctional octyl-amino supports have been prepared using ethylenediamine and hexylendiamine (oceda and ochda) and utilized to immobilize five lipases (lipases a (cala) and b (calb) from candida antarctica, lipases from thermomyces lanuginosus (tll), from rhizomucor miehei (rml) and from candida rugosa (crl) and the phospholipase lecitase ultra (lu). using ph 5 and 50 mm sodium acetate, the immobilizations proceeded via interfacial activation on the octyl layer, after some ion ...201627196882
biotransformation of salpichrolides a, c, and g by three filamentous fungi.incubation of salpichrolide a (1) with rhizomucor miehei produced hydroxylation in rings b and c (c-7 and c-12) and led to c-5-c-6 epoxide opening, while incubation of salpichrolides c (2) and g (3) with r. miehei led to epoxide opening at the c-24-c-25 and c-5-c-6 positions, respectively. biotransformation of salpichrolide a (1) with cunninghamella elegans produced stereoselective hydroxylated, oxidized, and reduced derivatives in different positions of the a, b, and c rings and c-5-c-6 epoxide ...201627285201
synthesis of geranyl propionate in a solvent-free medium using rhizomucor miehei lipase covalently immobilized on chitosan-graphene oxide beads.the chemical route of producing geranyl propionate involves the use of toxic chemicals, liberation of unwanted by-products as well as problematic separation process. in view of such problems, the use of rhizomucor miehei lipase (rml) covalently bound onto activated chitosan-graphene oxide (rml-cs/go) support is suggested. following analyses using fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, and thermogravimetry, propertie ...201727341522
changes in volatile composition and sensory properties of iranian ultrafiltered white cheese as affected by blends of rhizomucor miehei protease or camel chymosin.the effect of using various combinations of rhizomucor miehei protease and camel chymosin (100:0, 75:25, 50:50, 25:75, and 0:100, respectively) on volatile composition and sensory scores in iranian ultrafiltered white cheese was studied during 90d of ripening. a solid-phase microextraction-gas chromatography-mass spectrometric method was used for determining the volatile compounds of the cheeses. forty compounds including esters (12), acids (6), ketones (9), alcohols (3), and miscellaneous compo ...201627423952
incorporation of palmitic acid or stearic acid into soybean oils using enzymatic interesterification.incorporations of nature fatty acids which were palmitic acid and stearic acid into the end positions of soybean oils were done using sn-1,3 specific immobilised lipase from rhizomucor miehei at different ratios in order to produce symmetrical triglycerides without changing the fatty acids at sn-2 position. the optimum ratio for the process was 25:75 w/w. there were 19.2% increase of sfa for p25 and 16% increase for s25 at the sn-1,3 positions. the research findings indicated that the structured ...201627477075
interfacial activation of lipases on hydrophobic support and application in the synthesis of a lubricant ester.n-octyl oleate was synthetized by enzymatic esterification reaction of oleic acid and n-octanol. lipases from porcine pancreatic (ppl), mucor javanicus (mjl), candida sp. (cala), rhizomucor miehei (rml) and thermomyces lanuginosus (tll) were immobilized via interfacial activation on poly-methacrylate particles (pma) and tested as biocatalysts. their catalytic properties were determined in the hydrolysis of olive oil emulsion. among them, tll-pma was the biocatalyst that yielded the highest hydro ...201627477246
tailoring the internal structure of liquid crystalline nanoparticles responsive to fungal lipases: a potential platform for sustained drug release.lipases are key components in the mechanisms underlying the persistence and virulence of infections by fungi, and thus also promising triggers for bioresponsive lipid-based liquid crystalline nanoparticles. we here propose a platform in which only a minor component of the formulation is susceptible to cleavage by lipase and where hydrolysis triggers a controlled phase transition within the nanoparticles that can potentially allow for an extended drug release. the responsive formulations were com ...201627518452
oxidation stability of o/w emulsion prepared with linolenic acid enriched diacylglycerol.the sn-1,3-regiospecific rhizomucor miehei lipase (lipozyme rm im) was employed to produce structured diacylglycerol (sl-dag), which contained 67.3 mol% dag with 27.2 area% of c18:3. to investigate the oxidative stability of the sl-dag in emulsion form, 5% oil-in-water (o/w) emulsions were prepared with 200 and 400 ppm sinapic acid. it was shown that the hydroperoxide values of the control (without any antioxidant) was the highest (117.7 meq/l) on day 43 of storage and thereafter the value decre ...201627627797
production of biodiesel from acid oil via a two-step enzymatic transesterification.a two-step enzymatic transesterification process in a solvent-free system has been developed as a novel approach to the production of biodiesel using acid oil from rice bran oil soapstock. the acid oil consisted of 53.7 wt% fatty acids, 2.4 wt% monoacylglycerols, 9.1 wt% diacylglycerols, 28.8 wt% triacylglycerols, and 6.0 wt% others. three immobilized lipases were evaluated as potential biocatalysts, including novozym 435 from candida antarctica, lipozyme rm im from rhizomucor miehei, and lipozy ...201627733740
purification and properties of extracellular lipases with transesterification activity and 1,3-regioselectivity from rhizomucor miehei and rhizopus oryzae.rhizomucor miehei nrrl 5282 and rhizopus oryzae nrrl 1526 can produce lipases with high synthetic activities in wheat bran-based solid-state culture. in this study, the purification and biochemical characterization of the lipolytic activities of these lipases are presented. sds-page indicated a molecular mass of about 55 and 35 kda for the purified r. miehei and rh. oryzae enzymes, respectively. p-nitrophenyl palmitate (pnpp) hydrolysis was maximal at 40°c and ph 7.0 for the r. miehei lipase, an ...201727780957
desorption of lipases immobilized on octyl-agarose beads and coated with ionic polymers after thermal inactivation. stronger adsorption of polymers/unfolded protein composites.lipases from candida antarctica (isoform b) and rhizomucor miehei (calb and rml) have been immobilized on octyl-agarose (oc) and further coated with polyethylenimine (pei) and dextran sulfate (ds). the enzymes just immobilized on oc supports could be easily released from the support using 2% sds at ph 7, both intact or after thermal inactivation (in fact, after inactivation most enzyme molecules were already desorbed). the coating with pei and ds greatly reduced the enzyme release during thermal ...201728067789
ultrasound pretreatment as a novel approach for intensification of lipase catalyzed esterification of tricaprylin.the current work deals with ultrasound assisted intensification of synthesis of tricaprylin based on the enzyme catalyzed reaction of caprylic acid and glycerol with novel approach of using ultrasound in only the initial stages of the reaction. two types of immobilized lipases as lipozyme rm (rhizomucor miehei) and novozym 435 (candida antarctica) have been used in the work. the effect of ultrasonic conditions such as treatment time and power as well as the reaction conditions such as substrate ...201728069208
enzymatic and solid-phase synthesis of new donepezil-based l- and d-glutamic acid derivatives and their pharmacological evaluation in models related to alzheimer's disease and cerebral ischemia.previously, we have described n-bz-l-glu[nh-2-(1-benzylpiperidin-4-yl)ethyl]-o-nhex (iqm9.21, l-1) as an interesting multifunctional neuroprotective compound for the potential treatment of neurodegenerative diseases. here, we describe new derivatives and different synthetic routes, such as chemoenzymatic and solid-phase synthesis, aiming to improve the previously described route in solution. the lipase-catalysed amidation of l- and d-glu diesters with n-benzyl-4-(2-aminoethyl)piperidine has been ...201728242552
the first description of a hormone-sensitive lipase from a basidiomycete: structural insights and biochemical characterization revealed bjerkandera adusta baestb as a novel esterase.the heterologous expression and characterization of a hormone-sensitive lipases (hsl) esterase (baestb) from the basidiomycete fungus bjerkandera adusta is reported for the first time. according to structural analysis, amino acid similarities and conservation of particular motifs, it was established that this enzyme belongs to the (hsl) family. the cdna sequence consisted of 969 nucleotides, while the gene comprised 1133, including three introns of 57, 50, and 57 nucleotides. through three-dimen ...201728251842
establishment and application of a modified membrane-blot assay for rhizomucor miehei lipases aimed at improving their methanol tolerance and thermostability.directed evolution has been proved an effective way to improve the stability of proteins, but high throughput screening assays for directed evolution with simultaneous improvement of two or more properties are still rare. in this study, we aimed to establish a membrane-blot assay for use in the high-throughput screening of rhizomucor miehei lipases (rmls). with the assistance of the membrane-blot screening assay, a mutant e47k named g10 that showed improved thermal stability was detected in the ...201728465058
biophysical evaluation of milk-clotting enzymes processed by high pressure.high pressure processing (hpp) is able to promote changes in enzymes structure. this study evaluated the effect of hp on the structural changes in milk-clotting enzymes processed under activation conditions for recombinant camel chymosin (212mpa/5min/10°c), calf rennet (280mpa/20min/25°c), bovine rennet (222mpa/5min/23°c), and porcine pepsin (50mpa/5min/20°c) and under inactivation conditions for all enzymes (600mpa/10min/25°c) including the protease from rhizomucor miehei. in general, it was fo ...201728578031
directed evolution of a β-mannanase from rhizomucor miehei to improve catalytic activity in acidic and thermophilic conditions.β-mannanase randomly cleaves the β-1,4-linked mannan backbone of hemicellulose, which plays the most important role in the enzymatic degradation of mannan. although the industrial applications of β-mannanase have tremendously expanded in recent years, the wild-type β-mannanases are still defective for some industries. the glycoside hydrolase (gh) family 5 β-mannanase (rmman5a) from rhizomucor miehei shows many outstanding properties, such as high specific activity and hydrolysis property. howeve ...201728588644
improved activity of lipase immobilized in microemulsion-based organogels for (r, s)-ketoprofen ester resolution: long-term stability and reusability.microemulsion-based organogels (mbgs) were effectively employed for the immobilization of four commonly used lipases. during the asymmetric hydrolysis of ketoprofen vinyl ester at 30 °c for 24 h, lipase from rhizomucor miehei and mucor javanicus immobilized in microemulsion-based organogels (rml mbgs and mjl mbgs) maintained good enantioselectivities (eep were 86.2% and 99.2%, respectively), and their activities increased 12.8-fold and 7.8-fold, respectively, compared with their free forms. they ...201528626708
immobilization of rhizomucor miehei lipase on a polymeric film for synthesis of important fatty acid esters: kinetics and application studies.the present work deals with the designing of biocompatible hybrid blend of cellulosic copolymers made of hydroxypropyl methylcellulose (hmc) and chitosan (chi) for immobilization of rhizomucor miehei lipase (rml), in order to construct the robust biocatalytic system to synthesize industrially important dodecanoate compounds (fatty acid esters). the present biocatalyst hmc:chi:rml was characterized in detail by various physical and biochemical methods and subsequently applied for the synthesis of ...201728676893
high level expression of β-mannanase (rmman5a) in pichia pastoris for partially hydrolyzed guar gum production.partially hydrolyzed guar gum (phgg), an important supplemental dietary fiber, has been used as food ingredient in many industries. in this study, a novel β-mannanase gene (rmman5a) from rhizomucor miehei was successfully expressed in pichia pastoris and subjected for phgg production. enzyme activity of fermentation supernatant reached 85,200uml(-1) after 168h high cell density fermentation. the purified rmman5a exhibited the highest enzyme activity at ph 7.0 and 65°c. rmman5a was then employed ...201728756198
co-expression of lipase isozymes for enhanced expression in pichia pastoris.to enhance the expression level of overall lipase isozymes which catalyze the same reaction in p. pastoris through co-expression of isozymes from different sources, several types of co-expression ways were constructed to determine the co-expression efficiencies of lipase isozymes in p. pastoris. the results showed that the kex2 mediated co-expression of lipase isozymes could express rhizomucor miehei lipase (rml) and thermomyces lanuginosus lipase (tll) simultaneously, and gs-rmk-ktl displayed a ...201728763110
lipase-catalyzed synthesis of oleoyl-lysophosphatidylcholine by direct esterification in solvent-free medium without water removal.in this work, the synthesis of oleoyl-lysophosphatidylcholine by lipase-catalyzed esterification of glycerophosphocholine (gpc) and free oleic acid in a reaction medium without solvent is presented. the complete solubilisation of gpc, which is a crucial issue in non-polar liquids such as melted free fatty acids, was reached by heating the gpc/oleic acid mixture at high temperature during a short time. the immobilized lipase from rhizomucor miehei (lipozyme rm-im) was shown to catalyze the reacti ...201728794312
bio-based production of dimethyl itaconate from rice wine waste-derived itaconic acid.dimethyl itaconate is an important raw material for copolymerization, but it is not synthesized from itaconic acid by organisms. moreover, corynebacterium glutamicum is used as an important industrial host for the production of organic acids, but it does not metabolize itaconic acid. therefore, the biosynthetic route towards dimethyl itaconate from itaconic acid is highly needed. in this study, we developed a biological procedure for dimethyl itaconate production from rice wine waste-derived ita ...201728846199
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