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the stereospecificity of the ferrous-ion-dependent alcohol dehydrogenase from zymomonas mobilis.alcohol dehydrogenase from zymomonas mobilis has been found to transfer the pro-r hydrogen of nadh to acetaldehyde. this is the first report of the stereospecificity of a dehydrogenase in the mechanistic and structural class of fe2+-dependent alcohol dehydrogenases and offers an opportunity to expand mechanistic hypotheses relating stereospecificity, reaction mechanism and reaction thermodynamics in dehydrogenases.19892924772
liquid residence time distributions in immobilized cell bioreactors.previous work has demonstrated that high ethanol productivities can be achieved using yeast or bacterial cells adsorbed onto the surface of ion exchange resin in vertical packed bed bioreactors. the present work quantitatively characterizes the overall degree of backmixing in such reactors at two scales of operation: 2.0 and 8.0 l. stimulus-response experiments, using two solvents (2,3-butanediol and 2-ethoxyethanol) as tracers, were performed to measure the liquid phase residence time distribut ...198918587958
growth inhibition of zymomonas mobilis atcc 10988 by ammonium ions. 198918588103
effect of intraparticle diffusion in ethanol fermentation by immobilized zymomonas mobilis. 198818584650
expression of different levels of ethanologenic enzymes from zymomonas mobilis in recombinant strains of escherichia coli.the expression of zymomonas mobilis genes encoding pyruvate decarboxylase and alcohol dehydrogenase ii in escherichia coli converted this organism from the production of organic acids to the production of ethanol. ethanol was produced during both anaerobic and aerobic growth. the extent to which these ethanologenic enzymes were expressed correlated with the extent of ethanol production. the replacement of organic acids with ethanol as a metabolic product during aerobic and anaerobic growth resul ...198816347553
phosphoglycerate kinase gene from zymomonas mobilis: cloning, sequencing, and localization within the gap operon.the zymomonas mobilis gene encoding phosphoglycerate kinase (ec 2.7.3.2), pgk, has been cloned into escherichia coli and sequenced. it consists of 336 amino acids, including the n-terminal methionine, with a molecular weight of 41,384. this promoterless gene is located 225 base pairs downstream from the gap gene and is part of the gap operon. previous studies have shown that the specific activities of glyceraldehyde-3-phosphate dehydrogenase and phosphoglycerate kinase do not change coordinately ...19882832389
localization and mapping of co2 fixation genes within two gene clusters in rhodobacter sphaeroides.two fructose 1,6-bisphosphatase structural genes (fbpa and fbpb) have been identified within two unlinked gene clusters that were previously shown to contain the rhodobacter sphaeroides sequences that code for form i and form ii ribulose 1,5-bisphosphate carboxylase-oxygenase and phosphoribulokinase. the fbpa and fbpb genes were localized to a region immediately upstream from the corresponding prka and prkb sequences and were found to be transcribed in the same direction as the phosphoribulokina ...19882834328
cosmid cloning of five zymomonas trp genes by complementation of escherichia coli and pseudomonas putida trp mutants.a library of zymomonas mobilis genomic dna was constructed in the broad-host-range cosmid plafr1. the library was mobilized into a variety of escherichia coli and pseudomonas putida trp mutants by using the helper plasmid prk2013. five z. mobilis trp genes were identified by the ability to complement the trp mutants. the trpf, trpb, and trpa genes were on one cosmid, while the trpd and trpc genes were on two separate cosmids. the organization of the z. mobilis trp genes seems to be similar to th ...19882838460
comparison of the structural genes for pyruvate decarboxylase in different zymomonas mobilis strains.the nucleotide sequence of the pyruvate decarboxylase gene from zymomonas mobilis atcc 29191 was determined and compared with the sequence of the corresponding gene in z. mobilis atcc 31821. differences were found, leading to variations on the amino acid level and to different sites for restriction endonucleases.19882838467
the kinetics of glucose-fructose oxidoreductase from zymomonas mobilis.glucose-fructose oxidoreductase operates by a classic ping-pong mechanism with a single site for all substrates: glucose, fructose, gluconolactone and sorbitol. the km values for these substrates were determined. the values of kcat are 200 s-1 and 0.8 s-1 for the forward and reverse directions respectively. the overall catalytic process consists of two half-reactions with alternate reduction of nadp+ and oxidation of nadph tightly bound to the enzyme. reduction of enzyme-nadp+ by glucose and oxi ...19883356190
overexpression, purification and properties of alcohol dehydrogenase iv from saccharomyces cerevisiae.we have purified adhiv, a novel alcohol dehydrogenase (adh) isozyme in the yeast saccharomyces cerevisiae, after increasing the normally low amount of adhiv protein in laboratory strains. this was done by overexpression of the structural gene (adh4) on a 2micro-based multicopy vector. characterization of the purified enzyme revealed a dimeric structure as well as a different substrate specificity and ph profile as compared to other alcohol dehydrogenase isozymes. on the other hand, we could demo ...19883282541
expression and stability of a recombinant plasmid in zymomonas mobilis and escherichia coli.a recombinant plasmid was constructed by ligating ecori digests of the plasmid cloning vector pbr325 and pzmo2, one of the natural plasmids of zymomonas mobilis atcc 10988. this vector, named pds212 (total size 7.9 kb), which was able to transform escherichia coli efficiently, was also transferred to z. mobilis hosts by mobilization during conjugation using the helper plasmid prk2013. pds212 was inherited stably in both e. coli and z. mobilis hosts and could be recovered intact from them. marker ...19873309139
genetic engineering of ethanol production in escherichia coli.the genes encoding essential enzymes of the fermentative pathway for ethanol production in zymomonas mobilis, an obligately ethanologenic bacterium, were inserted into escherichia coli under the control of a common promoter. alcohol dehydrogenase ii and pyruvate decarboxylase from z. mobilis were expressed at high levels in e. coli, resulting in increased cell growth and the production of ethanol as the principal fermentation product from glucose. these results demonstrate that it is possible to ...19873322191
pyruvate decarboxylase of zymomonas mobilis: isolation, properties, and genetic expression in escherichia coli.pyruvate decarboxylase (ec 4.1.1.1) from zymomonas mobilis purified to homogeneity by using dye-ligand and ion-exchange chromatography. antibodies produced against the enzyme and the amino-terminal sequence obtained for the pure enzyme were used to select and confirm the identity of a genomic clone encoding the enzyme selected from a genomic library of z. mobilis dna cloned into puc9. the genomic fragment encoding the enzyme expressed high levels of pyruvate decarboxylase in escherichia coli. po ...19873546263
cloning and sequencing of the alcohol dehydrogenase ii gene from zymomonas mobilis.the gene which encodes alcohol dehydrogenase ii (adhb) from zymomonas mobilis was cloned in escherichia coli as a 1.4-kilobase dna fragment by using a novel indicator plate which directly detects the expression of this activity by recombinant colonies. the dna sequence for this clone contained an open reading frame encoding a polypeptide of 383 amino acids, with a molecular weight of 40,141. although this protein exhibited very little homology with other known alcohol dehydrogenases, the predict ...19873584063
glycolytic flux in zymomonas mobilis: enzyme and metabolite levels during batch fermentation.the rate at which z. mobilis (entner-doudoroff pathway) converts high concentrations of glucose (20%) into ethanol plus co2 changes as ethanol accumulates in the surrounding broth. this decline in glycolytic activity (per milligram of cell protein) does not result from inhibitory effects of ethanol, which can be reversed immediately by ethanol removal. the peak of fermentative activity (58 mumol of co2 evolved per mg of cell protein per h) occurred after the accumulation of 1.1% ethanol (18 h) a ...19873611027
glyceraldehyde-3-phosphate dehydrogenase gene from zymomonas mobilis: cloning, sequencing, and identification of promoter region.the gene encoding glyceraldehyde-3-phosphate dehydrogenase was isolated from a library of zymomonas mobilis dna fragments by complementing a deficient strain of escherichia coli. it contained tandem promoters which were recognized by e. coli but appeared to function less efficiently than the enteric lac promoter in e. coli. the open reading frame for this gene encoded 337 amino acids with an aggregate molecular weight of 36,099 (including the n-terminal methionine). the primary amino acid sequen ...19873680173
behavior of the incw plasmid sa in zymomonas mobilis.the stability of the broad-host-range incw r plasmid sa in zymomonas mobilis zm6100(sa) was monitored using three antibiotic resistance markers carried by sa. when grown in batch culture without selection, zm6100(sa) rapidly lost the sa plasmid. when grown with selection for either kanamycin or spectinomycin resistance, the three sa markers were retained in at least 90% of the population, with spontaneous loss of chloramphenicol resistance being observed in the rest of the population. when zm610 ...19872962214
promoter and nucleotide sequences of the zymomonas mobilis pyruvate decarboxylase.dna sequence analysis showed that pyruvate decarboxylase (one of the most abundant proteins in zymomonas mobilis) contains 559 amino acids. the promoter for the gene encoding pyruvate decarboxylase was not recognized by escherichia coli, although the cloned gene was expressed at relatively high levels under the control of alternative promoters. the promoter region did not contain sequences which could be identified as being homologous to the generalized promoter structure for e. coli. hydropathy ...19873029037
nucleotide sequence of the pyruvate decarboxylase gene from zymomonas mobilis.pyruvate decarboxylase (ec 4.1.1.1), the penultimate enzyme in the alcoholic fermentation pathway of zymomonas mobilis, converts pyruvate to acetaldehyde and carbon dioxide. the complete nucleotide sequence of the structural gene encoding pyruvate decarboxylase from zymomonas mobilis has been determined. the coding region is 1704 nucleotides long and encodes a polypeptide of 567 amino acids with a calculated subunit mass of 60,790 daltons. the amino acid sequence was confirmed by comparison with ...19873029726
construction of a transposon containing a gene for polygalacturonate trans-eliminase from klebsiella oxytoca.a dna fragment containing a klebsiella oxytoca gene for polygalacturonate trans-eliminase was cloned into the kanamycin resistance transposon tn5. this new transposon, designated tn5-pga+, had a transposition frequency of 1 x 10(-6). the broad host range plasmid pr751::tn5-pga+ was conjugally transferred to a variety of genetic backgrounds. the ability to degrade polygalacturonate was expressed in aeromonas hydrophila, alcaligenes eutrophus, azotomonas insolita, escherichia coli, pseudomonas put ...19873034186
gene expression in zymomonas mobilis: promoter structure and identification of membrane anchor sequences forming functional lacz' fusion proteins.we have described a procedure for the isolation of lacz' fusion genes which contain anchor sequences conferring membrane association. this method was used to isolate fragments of dna from zymomonas mobilis which contain promoter activity and amino-terminal sequences. the sequences and transcriptional initiation sites of three of these were compared. both escherichia coli and z. mobilis recognized similar regions of dna for transcriptional initiation. five to eight consecutive hydrophobic amino a ...19873034853
homology of saccharomyces cerevisiae adh4 to an iron-activated alcohol dehydrogenase from zymomonas mobilis.insertion of the transposable element ty at the adh4 locus results in increased levels of a new alcohol dehydrogenase (adh) activity in saccharomyces cerevisiae. the dna sequence of this locus has been determined. it contains a long open reading frame which is not homologous to the other adh isozymes that have been characterized in s. cerevisiae nor does it show obvious homology to drosophila adh. the hypothetical adh does, however, show strong homology to the sequence of an iron-activated adh f ...19872823079
expression vector for zymomonas mobilis.this study describes the construction of several useful cloning vectors which can be conjugated from escherichia coli into zymomonas mobilis at high frequency, approaching 10 per donor or recipient. these vectors contain a broad-host-range replicon and mob site from rsf1010, a chloramphenicol acyltransferase gene under the control of an enteric consensus promoter, and a second mob site (originally derived from rp4). the addition of this second mob site appears to be responsible for a 2-order-of- ...198716347272
zymomonas mobilis mutants with an increased rate of alcohol production.two new derivatives of zymomonas mobilis cp4 were isolated from enrichment cultures after 18 months of serial transfers. these new strains were selected for the ability to grow and produce ethanol rapidly on transfer into fresh broth containing ethanol and allyl alcohol. ethanol production by these strains was examined in batch fermentations under three sets of conditions. both new derivatives were found to be superior to the parent strain cp4 with respect to the speed and completeness of glucos ...198716347373
fermentation of d-xylose and l-arabinose to ethanol by erwinia chrysanthemi.erwinia spp. are gram-negative facultative anaerobes within the family enterobacteriacae which possess several desirable traits for the conversion of pentose sugars to ethanol, such as the ability to ferment a broad range of carbohydrates and the ease with which they can be genetically modified. twenty-eight strains of erwinia carotovora and e. chrysanthemi were screened for the ability to ferment d-xylose to ethanol. e. chrysanthemi b374 was chosen for further study on the basis of its superior ...198716347426
fermentation of d-xylose to ethanol by genetically modified klebsiella planticola.d-xylose is a plentiful pentose sugar derived from agricultural or forest residues. enteric bacteria such as klebsiella spp. ferment d-xylose to form mixed acids and butanediol in addition to ethanol. thus the ethanol yield is normally low. zymomonas spp. and most yeasts are unable to ferment xylose, but they do ferment hexose sugars to ethanol in high yield because they contain pyruvate decarboxylase (ec 4.1.1.1), a key enzyme that is absent from enteric bacteria. this report describes the ferm ...198716347427
production of acetaldehyde by zymomonas mobilis.mutants of zymomonas mobilis were selected for decreased alcohol dehydrogenase activity by using consecutively higher concentrations of allyl alcohol. a mutant selected by using 100 mm allyl alcohol produced acetaldehyde at a level of 4.08 g/liter when the organism was grown in aerated batch cultures on a medium containing 4.0% (wt/wt) glucose. on the basis of the amount of glucose utilized, this level of acetaldehyde production represents nearly 40% of the maximum theoretical yield. acetaldehyd ...198716347497
mathematical modeling of ethanol production by immobilized zymomonas mobilis in a packed bed fermenter.a mathematical model which describes ethanol production in a packed bed fermenter containing. zymomonas mobilis entrapped in small spheres of calcium alginate within a packed bed fermenter has been developed. the equations combine simultaneous diffusion and reaction as well as a complex flow pattern to calculate glucose and ethanol profiles in the column type reactor. as part of the study, diffusivity values for glucose and ethanol in cell-loaded calcium alginate were determined. also a freecell ...198718576429
fermentation kinetics of zymomonas mobilis near zero growth rate.the fermentation kinetics zymomonas mobilis were studied near zero growth rate in fed-batch cultures and continuous cultures with complete cell recycle. the results show the ethanol enhances that specific substrate conversion rate under these conditions. the maximum achievable ethanol concentration in continuous cultures with cell recycle (66 g/l) was significantly lower than in fed-batch cultures (100 g/l). the results indicate that growth-rate-independent metabolism is not instantaneous and ca ...198718576479
continuous production of ethanol with zymomonas mobilis growing on jerusalem artichoke juice. 198718576518
simultaneous saccharification/fermentation with zymomonas mobilis. 198618553851
ethanol production from starch by a coimmobilized mixed culture system of aspergillus awamori and zymomonas mobilis.the production of ethanol from starch by a coimmobilized mixed culture system of aerobic and anaerobic microorganisms in ca-alginate gel beads was investigated. the mold aspergillus awamori was used as an aerobic amylolytic microorganism and an anaerobic bacterium, zymomonas mobilis, as an ethanol producer. by controlling the mixing ratio of the microorganisms in the inoculum size, a desirable coimmobilized mixed culture system, in which the aerobic mycelia grew on and near the oxygen-rich surfa ...198618555292
anaerobic calorimetry of zymomonas mobilis using a heat-flux sensor.a relatively simple and inexpensive anaerobic calorimeter was designed and evaluated by using a hy-cal engineering bi-7 bidirectional heat-flux sensor to measure heat output from magnetically stirred i-l flask fermentations. the production of ethanol and cumulative heat output by zymomonas mobilis were both linearly proportional to glucose concentrations up to 160 g/l.198618555293
the inhibition of the maximum specific growth and fermentation rate of zymomonas mobilis by ethanol.the inhibition of the maximum specific growth and fermentation rate of zymomonas mobilis by ethanol was studied in turbidostat cultures at constant and stepwise changed ethanol concentrations. up to 50 g/l ethanol, the inhibition kinetics can be approximated by a linear relationship between the specific growth rate and the ethanol concentration. above this level, deviations from this linearity are observed. the specific fermentation rates were less inhibited by ethanol than was the specific grow ...198618555360
effect of temperature and ph on immobilized zymomonas mobilis for continuous production of ethanol.the effects of temperature and inlet ph of the medium on the ethanol productivity and activity of the immobilized z. mobilis cells during continuous fermentation of glucose have been studied at various temperatures and ph. on changing the temperature from one steady state level to a new one, 6-8 h were required in order to fully experience the effect of a change in temperature; whereas 8-20 h were required on changing the ph. the optimum temperature of 37 degrees c and a broad ph range of 4.4-6. ...198618555399
kinetics of batch fermentations for ethanol production with zymomonas mobilis growing on jerusalem artichoke juice.a flocculent strain of zymomonas mobilis was used for ethanol production from jerusalem artichoke juice containing 113-245 g/l sugar in batch fermentation. the kinetic and yields parameters are calculated using a new method based on polynomial equations for the variation of biomass, ethanol, and sugar concentrations with time. the results show that. z. mobilis can convert rapidly and efficiently jerusalem artichoke juice to ethanol. when a sugar concentration of 248 gl was used, 100 g/l ethanol ...198618555403
fermentation kinetics of zymomonas mobilis at high ethanol concentrations: oscillations in continuous cultures.substrate-limited continuous culture results at 47 g/l ethanol show that the maintenance factor and the yield factor of an unstructured maintenance model are lower compared to the values at 23 g/l ethanol. computing the results according to a structured two-compartment model predicts an enhanced turnover rate of the k-compartment (rna fraction) by ethanol, resulting in a lower steady-state amount of k-compartment. this is in agreement with experimentally determined rna fractions. the parameters ...198618555405
thermal tolerance of zymomonas mobilis: temperature-induced changes in membrane composition.the membrane composition of zymomonas mobilis changed dramatically in response to growth temperature. with increasing temperature, the proportion of vaccenic acid declined with an increase in myristic acid, the proportion of phosphatidylcholine and cardiolipin increased with decreases in phosphatidylethanolamine and phosphatidylglycerol, and the phospholipid/protein ratio of the membrane declined. these changes in membrane composition were correlated with changes in thermal tolerance and with ch ...198616347087
transfer of plasmids to an antibiotic-sensitive mutant of zymomonas mobilis.wild-type strains of zymomonas mobilis exhibit multiple antibiotic resistance and thus restrict the use of many broad-host-range plasmids in them as cloning vehicles. antibiotic-sensitive mutants of z. mobilis were isolated and used as hosts for the conjugal transfer of broad-host-range plasmids from escherichia coli. such antibiotic-sensitive strains can facilitate the application of broad-host-range plasmids to the study of z. mobilis.198616347136
zymomonas mobilis: a bacterium for ethanol production. 198614545375
the two alcohol dehydrogenases of zymomonas mobilis. purification by differential dye ligand chromatography, molecular characterisation and physiological roles.the two alcohol dehydrogenases found in zymomonas mobilis have each been purified using dye-ligand chromatography and affinity elution with nucleotides. the isoenzyme with lower electrophoretic mobility (zadh-1) is a zinc enzyme with properties essentially similar to preparations described elsewhere. the faster isoenzyme (zadh-2) accounted for some 90% of the ethanol-oxidizing activity in freshly prepared extracts and corresponded to the iron-activated enzyme previously described. this enzyme wa ...19862935393
nmr studies of [1-2h]glucose metabolism in zymomonas mobilis.in complementary experiments the metabolism of [1-2h]glucose in h2o and of unlabelled glucose in 2h2o by zymomonas mobilis was examined. the utilization of [1-2h]glucose by z. mobilis was monitored by high-resolution 2h nmr. the deuterium-labelling pattern and stereochemistry of the ethanols produced from the metabolism of [1-2h]glucose and unlabelled glucose in 2h2o were determined by a combination of 13c and 1h nmr and selective enzyme action. the labelling patterns were explained in terms of ...19862940086
glucose-fructose oxidoreductase, a new enzyme isolated from zymomonas mobilis that is responsible for sorbitol production.the enzymes responsible for sorbitol formation in zymomonas mobilis were investigated. a previously undescribed enzyme catalyzes the intermolecular oxidation-reduction of glucose and fructose to form gluconolactone and sorbitol. this enzyme has been purified; it had a subunit size of 40,000 daltons and is probably tetrameric at low ph. it contained tightly bound nadp as the hydrogen carrier and did not require any added cofactor for activity. in addition, a gluconolactonase has been isolated, al ...19863745122
effect of ethanol and heat stresses on the protein pattern of zymomonas mobilis.heat or ethanol shock of zymomonas mobilis enhanced the labeling by [35s]methionine of several polypeptides and induced the synthesis of a new polypeptide (molecular weight, 18,500) associated with the envelope fraction. these results indicate the existence of a typical heat-shock response in z. mobilis. this response could be involved in the induction of increased ethanol tolerance in z. mobilis cells.19863949711
isolation and properties of the glycolytic enzymes from zymomonas mobilis. the five enzymes from glyceraldehyde-3-phosphate dehydrogenase through to pyruvate kinase.the five glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, enolase and pyruvate kinase were each purified from extracts of zymomonas mobilis cells, by using dye-ligand chromatography as the principal step. two procedures, producing three and two of the enzymes respectively, are described in detail. z. mobilis glyceraldehyde-phosphate dehydrogenase was found to be similar in most respects to the enzyme from other sources, except for hav ...19863026343
mechanism of ethanol inhibition of fermentation in zymomonas mobilis cp4.accumulation of alcohol during fermentation is accompanied by a progressive decrease in the rate of sugar conversion to ethanol. in this study, we provided evidence that inhibition of fermentation by ethanol can be attributed to an indirect effect of ethanol on the enzymes of glycolysis involving the plasma membrane. ethanol decreased the effectiveness of the plasma membrane as a semipermeable barrier, allowing leakage of essential cofactors and coenzymes. this leakage of cofactors and coenzymes ...19854044518
gluconate kinase from zymomonas mobilis: isolation and characteristics.the enzyme gluconate kinase ec 2.7.1.12 has been found at high levels in glucose-grown zymomonas mobilis cells. a simple procedure, based on differential dye-ligand chromatography, has been used to isolate the enzyme, purifying it some 600-fold. the purified enzyme is a monomer of molecular weight 18,000 da, which is much smaller than other gluconate kinases reported. it has a relatively low affinity for atp. (km = 1.5 mm), but high for gluconate (km = 0.33 mm), and has little activity with any ...19852990475
simultaneous purification and characterization of glucokinase, fructokinase and glucose-6-phosphate dehydrogenase from zymomonas mobilis.the three enzymes glucokinase (ec 2.7.1.2), fructokinase (ec 2.7.1.4) and glucose-6-phosphate dehydrogenase (ec 1.1.1.49) were isolated in high yield from extracts of zymomonas mobilis. the principal steps in the isolation procedures involved the use of selected dye-ligand adsorbent columns, with affinity elution of two of the three enzymes. glucokinase and fructokinase are dimeric proteins (2 x 33000 da and 2 x 28000 da respectively) and glucose-6-phosphate dehydrogenase is a tetramer (4 x 5200 ...19852992451
ethanol effect on the membrane protein pattern of zymomonas mobilis. 19852408556
d-glucose transport system of zymomonas mobilis.the properties of the d-glucose transport system of zymomonas mobilis were determined by measuring the uptake of nonmetabolizable analogs (2-deoxy-d-glucose and d-xylose) by wild-type cells and the uptake of d-glucose itself by a mutant lacking glucokinase. d-glucose was transported by a constitutive, stereospecific, carrier-mediated facilitated diffusion system, whereby its intracellular concentration quickly reached a plateau close to but not above the external concentration. d-xylose was tran ...198516346694
isolation of noninhibitory strains of zymomonas mobilis.wild-type zymomonas mobilis strains inhibit the growth of escherichia coli. we report the first isolation of noninhibitory strains, called zymomonas inhibition negative (zin), after treatment with n-methyl-n'-nitro-n-nitrosoguanidine. a standardized soft-agar overlay procedure for detecting e. coli growth inhibition was also developed.198516346764
cell immobilization in kappa-carrageenan for ethanol production.a combination of extended monod kinetics and the diffusional equation was used for evaluating the effectiveness factor of entrapped immobilized cells. based on the kinetics of zymomonas mobilis reported in the literature, the numerical results have revealed that the problem of mass transfer diffusional restrictions can be neglected by using small beads (1 mm in diameter) with a corresponding cell loading up to 276 g/l gel. on the basis of the numerical results obtained, the application of immobi ...198518553626
preparation and characterization of immobilized growing cells of zymomonas mobilis for ethanol production.zymomonas mobilis cells were entrapped in k. carrageenan. growth was observed with the immobilized cell preparation. the kinetic and yield parameters for the conversion of fructose to ethanol were nearly identical to free cells. the same preparation of immobilized cells was used in six repeated batch runs and at the end sixth-batch fructose was converted to ethanol more rapidly and efficiently with ethanol productivity of 14 g/l h and 96% conversion of fructose. the effect of high fructose and e ...198518553669
continuous production of ethanol from fructose by immobilized growing cells of zymomonas mobilis.immobilized growing cells of zymomonas mobilis were found to ferment rapidly and efficiently media containing 100 g/l fructose in a continuous reactor. a volumetric ethanol productivity of 94.8 g/l h was achieved at a substrate conversion of 75.5%. with 97% conversion of substrate the productivity was 28.4 g/l h. at fructose concentrations of 150 and 200 g/l substrate and product inhibitions limited the performance of the reactor. ethanol production was constant over a period of 55 days.198518553716
filament formation and ethanol production by zymomonas mobilis in adsorbed cell bioreactors.zymomonas mobilis immobilized on microporous ion exchange resins has previously been shown to allow the attainment of high ethanol productivities in packed-bed bioreactors. the formation of bacterial filaments after several days of continuous operation, however, had resulted in excessive pressure increases across the reactor bed. the present work examines techniques for controlling filament formation by z. mobilis in two reactor sizes (161 ml and 7.85 l) and a feed glucose concentration of 100 g ...198518553718
mathematical modelling of growth and substrate conversion of zymomonas mobilis at 30 and 35 degrees c.zymomonas mobilis was grown in continuous cultures at 30 and 35 degrees c. the specific substrate consumption rates at 35 degrees c were higher than those at 30 degrees c. an unstructured mathematical model based on the linear equation for substrate consumption provided a statistically adequate description for cultures grown at 35 degrees c but not for cultures grown at 30 degrees c. a structured two-compartment model described growth and substrate consumption well at both temperatures. some the ...198518553768
ethanol production by zymomonas mobilis in fed-batch fermentations.the production of ethanol by zymomonas mobilis nrrl b-4286 was studied in fed-batch cultures. initial percent (w/v) glucose, rate of feed, and quantity of 50%; (w/v) glucose feed were varied. glucose inhibition of growth rate occurred at concentrations greater than 8% (w/) feed was begun after 4 h incubation. feed volume was ca. 36%; of starting batch volume to get ca. 10%; (w/v) ethanol at harvest. the range of feed rates studied varied from 16%; batch volume/h (glucose concentration increased ...198418551733
influence of the presence of zymomonas anaerobia on the conversion of cellobiose, glucose, and xylose to ethanol by clostridium saccharolyticum.to convert sugar mixtures containing cellobiose, glucose, and xylose to ethanol in a single step, the possibility of using a coculture consisting of clostridium saccharolyticum and zymomonas anaerobia was studied. in monoculture, c. saccharolyticum utilized all three sugars; however, it preferentially utilized glucose and produced acetic acid in addition to ethanol. the formation of acetic acid from the metabolism of glucose inhibited the growth of c. saccharolyticum and, consequently, the utili ...198418553484
the enzymatic hydrolysis and fermentation of pretreated wood substrates.aspenwood chips were pretreated by steam explosion. the various wood fractions obtained were assayed for their ability to act as substrates for growth and cellulase production of different trichoderma and clostridium thermocellum species. steam exploded aspenwood was as efficiently utilized as solka floc and correspondingly high cellulase activities were detected in the various culture filtrates. when t. harzianum e58 was grown on increasing concentrations of solka floc, highest cellulase and xy ...198414545694
self-transmissible plasmid in zymomonas mobilis carrying antibiotic resistance.the cryptic plasmid prut41 from zymomonas mobilis was examined for its biological properties. this plasmid was found to be conjugally transferred from z. mobilis cp4 to escherichia coli bm21 and to carry genes for antibiotic resistance (gentamicin, kanamycin, and streptomycin). covalently closed circular plasmid dna was isolated from eight transconjugants of e. coli bm21. these plasmids were identical in mobility on agarose gels and exhibited the same restriction patterns as the native prut41 pl ...19846364969
antibacterial activity of different zymomonas mobilis strains.twenty different zymomonas mobilis strains were found to produce a substance which inhibited or killed various other zymomonas , escherichia coli, klebsiella pneumoniae and pseudomonas aeruginosa strains. this antibacterial activity could be detected in cross-streak tests and as zones of clearing in lawns of the test bacteria. when zymomonas strains are used as recipients in conjugation experiments, their antibacterial activity can be used to advantage for removal of unwanted donor cells from th ...19846427556
zymomonas ethanol fermentations.studies on various industrial raw materials indicate that a zymomonas process has its greatest commercial potential in fermenting starch-based substrates. high yields, productivities and ethanol concentrations can be achieved. genetic manipulation is now being used to extend the substrate range to lactose and other carbohydrates.19846444136
the structure of a novel polysaccharide isolated from zymomonas mobilis determined by nuclear magnetic resonance spectroscopy.a novel polysaccharide has been observed in vivo by 13c nuclear magnetic resonance (nmr) spectroscopy of the gram-negative bacterium, zymomonas mobilis. the polysaccharide, which was not removed from the z. mobilis cell by washing with 0.86% saline, was extracted by mild acid treatment. the structure was elucidated by a combination of nmr techniques, including proton and proton-carbon two-dimensional methods. the structure was determined to be -alpha-fructofuranosyl-(2-1)-beta-fructofuranosyl-(2 ...19846489351
31p nuclear magnetic resonance studies of the fermentation of glucose to ethanol by zymomonas mobilis.high resolution 31p nuclear magnetic resonance spectroscopy has been employed to study the fermentation of glucose to ethanol by zymomonas mobilis, strain zm4, a bacterium which uses the entner-doudoroff pathway. the levels of nucleoside triphosphates, sugar phosphates, udp-sugars and pi in intact fermenting cells have been studied with a time resolution of 1 min. it is suggested that a ph gradient is established across the cell membrane during fermentation and that the intracellular ph does not ...19846715367
transformation of zymomonas mobilis by a hybrid plasmid.the transformation of zymomonas mobilis by plasmid dna was achieved using a modification of the cacl2 method for escherichia coli. the highest frequency of transformation obtained was 5 x 10(3) transformants/micrograms dna. the success of the method depended upon the use of a plasmid which is a cointegrate between a z. mobilis cryptic plasmid and an e. coli plasmid carrying two selectable drug resistance markers.19846098907
use of differential dye-ligand chromatography with affinity elution for enzyme purification: 2-keto-3-deoxy-6-phosphogluconate aldolase from zymomonas mobilis.2-keto-3-deoxy-6-phosphogluconate aldolase (ec 4.1.2.14) has been isolated from extracts of zymomonas mobilis using differential dye-ligand chromatography and affinity elution with product/product analog. the one-step procedure gives an enzyme with specific activity 600 units mg-1. only 1 out of 47 dyes, procion yellow mx-gr, bound the enzyme completely in 20 mm phosphate buffer, ph 6.5. a column of navy he-r adsorbent was used first to remove most of the potentially adsorbing proteins.19846326622
use of differential dye-ligand chromatography with affinity elution for enzyme purification: 6-phosphogluconate dehydratase from zymomonas mobilis.using differential dye-ligand chromatography and affinity elution with a substrate analog, 6-phosphogluconate dehydratase (ec 4.2.1.12) has been isolated from extracts of zymomonas mobilis in a one-step procedure with 50% recovery. the specific activity of freshly isolated enzyme was 245 units mg-1. the enzyme contains iron, and it is rapidly inactivated in oxidizing conditions. it is inhibited by glycerophosphates, most strongly by the d-alpha-isomer which structurally corresponds to half of th ...19846326623
an iron-activated alcohol dehydrogenase.an alcohol dehydrogenase isolated from zymomonas mobilis was found to be activated by ferrous ions but not by zinc, after inactivation with metal-complexing agents. cobaltous ions also re-activated to a lesser extent. it is suggested that in this species the alcohol dehydrogenase naturally contains iron. kinetic studies on the iron-treated enzyme indicate an 'alcohol activation' phenomenon, which may have physiological relevance in overcoming product inhibition during fermentation.19836343121
high-productivity alcohol fermentations using zymomonas mobilis.a process is under development at the university of new south wales to produce fermentation ethanol faster and more efficiently. the process is based on the micro-organism zymomonas mobilis, which has higher specific rates of ethanol production and higher yields when compared with the traditionally used yeasts. by using hollow fibre membranes for cell recycle, high productivity continuous processes have been studied at laboratory-scale. pilot scale evaluations (500 litres) are now in progress th ...19836100832
lipid composition of zymomonas mobilis: effects of ethanol and glucose.zymomonas mobilis is an alcohol-tolerant microorganism which is potentially useful for the commercial production of ethanol. this organism was found to contain cardiolipin, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylcholine as major phospholipids. vaccenic acid was the most abundant fatty acid, with lesser amounts of myristic, palmitic, and palmitoleic acids. no branched-chain or cyclopropane fatty acids were found. previous studies in our laboratory have shown that ethanol ...19836853446
comparison of plasmids in strains of zymomonas mobilis.four strains of zymomonas mobilis were examined for their resistance to antimicrobial agents and found to have similar resistance profiles. plasmid dna was extracted and purified by cscl dye-buoyant density centrifugation; molecular weights were determined by agarose gel electrophoresis and electron microscopy. all four strains harbored a large plasmid (46 x 10(6) da) and a smaller plasmid (16-21 x 10(6) da) whose molecular weight was strain dependent. two strains, ag11 and atcc 10988, had small ...19836856691
controlling morphological instability of zymomonas mobilis strains in continuous culture.growth of zymomonas mobilis atcc 29191 and cp4 in a continuous stirred tank fermentor resulted in the selection of stable flocculating variants. factors responsible for enhancing the system pressures selective for the morphological variants were identified. by incorporating some modifications into the design of the fermentor, it was possible to achieve steady-state operation of the chemostat with both wild-type and flocculating strains. biochemical and microscopic studies were performed to eluci ...198316346320
controlling morphological instability of zymomonas mobilis strains in continuous culture.[this corrects the article on p. 1900 in vol. 45.].198316346393
expression of a lactose transposon (tn951) in zymomonas mobilis.the potential utility of zymomonas mobilis as an organism for the commercial production of ethanol would be greatly enhanced by the addition of foreign genes which expand its range of fermentable substrates. we tested various plasmids and mobilizing factors for their ability to act as vectors and introduce foreign genes into z. mobilis cp4. plasmid pgc91.14, a derivative of rp1, was found to be transferred from escherichia coli to z. mobilis at a higher frequency than previously reported for any ...198316346422
properties and application of immobilized beta-d-glucosidase coentrapped with zymomonas mobilis in calcium alginate.the enzyme beta-d-glucosidase has been immobilized on concanavalin a-sepharose to give a maximum loading of 2050 units/g dry weight of support material. the immobilized beta-d-glucosidase was also entrapped within calcium alginate gel spheres with apparently only 35% retention of activity when assayed with 10mm cellobiose. however, it was discovered that, unlike the immobilized enzyme, the entrapped immobilized enzyme was not subject to substrate inhibition up to 100mm cellobiose, suggesting tha ...198318548572
continuous simultaneous saccharification and fermentation of starch using zymomonas mobilis.a continuous process involving simultaneous saccharification and fermentation of liquefied starch has been developed using zymomonas mobilis. amyloglucosidase retention and cell recycle have been effected by using an amicon hollow-fiber membrane system with a mw cutoff of 5000. relatively high productivities of up to 60 g l(-1) h(-1) have been achieved at ethanol concentrations of 60-65 g/l. the system also offers the potential for reduced enzyme requirements for saccharification.198318548684
effects of temperature and ethanol concentration on the maintenance and yield coefficient of zymomonas mobilis. 198318551448
continuous ethanol production and cell growth in an immobilized-cell bioreactor employing zymomonas mobilis.ethanol-producing bioreactors employing cells of zymomonas mobilis attached to glass-fiber pads were operated continuously for as long as 28 days. ethanol production, which is related to bed-associated biomass levels, was found to occur in three distinct phases: an exponential phase, a linear phase, and a "steady-state" phase. after prolonged operation, a bacterial floc developed in the reactor. the maximum effluent ethanol concentration and the maximum volumetric productivity were 6.4% and 152 ...198218546350
fuel alcohol biosynthesis by zymomonas anaerobia: optimization studies.the optimum operating conditions for growth and ethanol production of zymomonas anaerobia atcc 29501 were established. the optimum ph range and temperature were found to be 5.0-6.0 and 35 degrees c, respectively. based on the results obtained from the temperature optimization study, an arrhenius-type temperature relationship for the specific growth rate was developed. the growth and ethanol production of this microbe also have been optimized in terms of concentrations of glucose, essential nutri ...198218546356
ethanol production by immobilized saccharomyces cerevisiae, saccharomyces uvarum, and zymomonas mobilis.saccharomyces cerevisiae nrrl y-2034, s, uvarum nrrl y-1347, and zymomonas mobilis nrrl b-806 each were separately immobilized in a ca-alginate matrix and incubated in the presence of a free-flowing and continuous 1, 3, 5, 10, or 20% (w/w) glucose solution. in general, the yeast cells, converted 100percnt; of the 1, 3, and 5% glucose to alcohol within 48 h and maintained such a conversion rate for at least two weeks. the bacterium converted ca. 90% (w/w) of the 1, 3, and 5% glucose to alcohol co ...198218546408
a filter fermenter-apparatus and control equipment.laboratory equipment for cultivation of microorganisms with the removal of cell-free medium is described. separation is accomplished by filtration through a membrane which is built into a top-driven fermenter. a system is presented which controls the flow rate by automatic cleaning of the filter. flow schemes for batch and continuous fermentations are shown. the filter fermenter is useful when studying continuous culture with feedback of biomass or processes where growth or product formation rat ...198218548501
genetic alteration of zymomonas mobilis for ethanol production. 19827066009
minimal medium for isolation of auxotrophic zymomonas mutants.a minimal medium which allowed the sustained, rapid growth of zymomonas mobilis and the isolation of a range of auxotrophic mutants was developed.19827125659
ethanol production by zymomonas mobilis and saccharomyces uvarum on aflatoxin-contaminated and ammonia-detoxified corn.zymomonas mobilis demonstrated greater fermentative activity than saccharomyces uvarum during the 1st day in the fermentation of two lots of aflatoxin-contaminated corn and two corresponding lots of ammonia-detoxified corn. final ethanol yields and conversion efficiencies were generally highest in zymomonas fermentations of ammonia-detoxified corn. aflatoxin levels in postfermentation solids from ammonia-detoxified corn all ranged below the food and drug administration feedstuff guideline of < 2 ...19817214236
characterization of the two alcohol dehydrogenases of zymomonas mobilis. 19817030207
comparison of ethanol production by different zymomonas strains.a comparison of the rates of growth and ethanol production by 11 different strains of zymomonas revealed a wide range of characteristics, with some strains being more tolerant of high sugar or ethanol concentrations and high incubation temperatures than others. some strains were unable to utilize sucrose; others produced large amounts of levan, and one strain grew well but produced no levan. one strain, cp4, was considerably better in all respects than most of the other strains and was chosen as ...198116345753
r-plasmid transfer in zymomonas mobilis.conjugal transfer of three incp1 plasmids and one incfii plasmid into strains of the ethanol-producing bacterium zymomonas mobilis was obtained. these plasmids were transferred at high frequencies from escherichia coli and pseudomonas aeruginosa into z. mobilis and also between different z. mobilis strains, using the membrane filter mating technique. most of the plasmids were stably maintained in z. mobilis, although there was some evidence of delayed marker expression. a low level of chromosoma ...198016345598
distribution of the phosphoenolpyruvate:glucose phosphotransferase system in fermentative bacteria.a number of selected fermentative bacteria were surveyed for the presence of the phosphoenolpyruvate:glucose phosphotransferase system, with particular attention to those organisms which ferment glucose by pathways other than the embden-meyerhof-parnas pathway. the phosphoenolpyruvate:glusoe phosphotransferase system was found in all homofermentative lactic acid bacteria tested that ferment glucose via the embden-meyerhof-parnas pathway, but in none of a group of heterofermentative species of la ...1979457606
the biology of zymomonas. 197716585
photoassimilation of acetate and metabolism of carbohydrate in chlorobium thiosulfatophilum.1. washed cell suspensions of chlorobium thiosulfatophilium form large amounts of a polyglucose in the light. addition of acetate to the cells increases the formation of polysaccharide considerable. during incubation in the dark, polysaccharide decreases with time, and organic acids such as succinic and propionic acid are excreted into the medium. 2. glucose isolated from cells which had photoassimilated 1-, 2-, and u-14c-acetate had a specific activity which lay between 1 and 2 times that of th ...1975808188
identification and grouping of bacteria by numerical analysis of their electrophoretic protein patterns.improved methods for the identification and grouping of bacteria by polyacrylamide gel electrophoresis of soluble proteins are described. electrophoretic protein patterns were obtained in rigorously standardized comditions. the results were much more reproducible than any described previously. some of the factors affecting reproducibility were; growth conditions, time and speed of centrifugation of extracts, and conditions of gel electrophoresis. protein patterns were compared by computing corre ...19751141858
microbiology of ripening honey.two main groups of bacteria, classified as gluconobacter and lactobacillus, are present in ripening honey. a third bacterial group, classified as zymomonas, and several types of yeast are occasionally isolated. both in natural honey and in synthetic syrup the bacterial population decreases in the course of the ripening process. lactobacillus and gluconobacter disappear after minimum moisture (about 18%) is reached, but the former does so sooner than the latter. the presence of these bacteria in ...197516350044
the vitamin nutrition of zymomonas anaerobia. 19734579123
glucose and fructose metabolism in zymomonas anaerobia.isotopic and enzymic evidence indicates that zymomonas anaerobia ferments glucose via the entner-doudoroff pathway. the molar growth yields with glucose (5.89) and fructose (5.0) are lower than those for the related organism zymomonas mobilis and the observed linear growth suggests that energetically uncoupled growth occurs. a survey of enzymes of carbohydrate metabolism revealed the presence of weak phosphofructokinase and fructose 1,6-diphosphate aldolase activities but phosphoketolase, transk ...19714259336
the nutrition of zymomonas anaerobia. 19704922569
effect of starvation on the viability and cellular constituents of zymomonas anaerobia and zymomonas mobilis. 19705488464
microcalorimetric study of glucose permeation in microbial cells.a microcalorimetric method for measuring the influence of extracellular glucose concentration on the rate of catabolism is described. this method has been applied to anaerobically growing cultures of zymomonas mobilis and of a respiratory-deficient ("petite") mutant of saccharomyces cerevisiae (strain yfa). the michaelian kinetics recorded with both organisms were apparently related to glucose transport. with z. mobilis, it was found that, in the range of glucose concentrations at which this org ...19685650082
[further observations on the antagonist action of zymomonas mobilis (linder) (1928), kluyver and van niel (1936)]. 19685761009
glucose-6-phosphate dehydrogenase in cell free extracts of zymomonas mobilis. 19684885089
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