Search results for "Zymomonas"

Influence of some physicochemical factors on the viscosity of aqueous levan solutions ofZymomonas mobilis

1998

Zymomonas mobilis strain 113 “S” produces levan – an extracellular, viscous, biologically active, non-toxic fructose polymer with a unique structure and extraordinary properties. This polysaccharide was isolated at two different degrees of purity by alcohol precipitation from aqueous solutions and was characterized with respect to some rheological properties and stability of viscous solutions. The effects of temperature, pH and salt concentration on the viscosity of 1–3% levan solutions were examined. The viscosity of levan solutions was found to be quite stable and reversible at room temperature over a wide range of pH from 4 to 11. The viscosity was slightly affected by increased salt con…

Stabilization of anti-leukemic enzyme l-asparaginase by immobilization on polysaccharide levan

2001

Abstract Biologically active fructose polymer levan from Zymomonas mobilis of different molecular mass (75 and 2000 kDa) was covalently coupled to anti-leukemic enzyme Erwinia carotovora l -asparaginase. The method used for the immobilization of the enzyme involved periodate oxidation of the polysaccharide, followed by reductive alkylation. A gentle periodate oxidation of levan (oxidation degree ≤24%) resulted in the highest residual enzyme activity (≥55%). The K m(app.) of glycoconjugates was higher than the K m of native l -asparaginase. The conjugation of l -asparaginase widened the optimum pH range of the enzyme. The electrophoretic mobility in polyacrylamide gel of glycoconjugates obta…

The effect of chemical treatment of stainless steel wire surfaces onZymomonas mobilis cell attachment and product synthesis

1998

The attachment, growth and product synthesis of non-flocculating Zymomonas mobilis cells, fixed in stainless steel wire spheres (WS), were investigated. The carrier surface was activated by treatment with titanium (IV) chloride (TiCl 4 ) and γ-aminopropyltriethoxysilane (AS) in an attempt to raise the efficiency in the immobilization of the cells. System productivity for ethanol and levan production, using cells immobilized on a modified stainless steel surface in the batch fermentation of a sucrose medium, rose as a result of increased biomass compared to the productivity of cells fixed on untreated (control) metal surfaces. Stabilized ethanol synthesis was demonstrated in the course of fo…

Levan production byZymomonas mobilis cells. Attached to plaited spheres

1997

In this work, an immobilization method for polymer-levan production by a non-flocculating Z mobilis culture was developed. The extent of cell attachment to the stainless steel wire surface, culture growth and product synthesis were described. It was established that during short-term passive immobilization of non-flocculating Z mobilis cells on a stainless steel wire surface, sufficient amounts of biomass for proper levan and ethanol fermentation could not be obtained. Adherence of cells was improved by pressing the paste-like biomass within stainless steel spheres knitted from wire with subsequent dehydration. Biomass fixed in metal spheres was used for repeated batch fermentation of levan…

Interrelationships between Growth Yield, ATPase and Adenylate Kinase Activities inZymomonas mobilis

2001

The presence of cytoplasmic and membrane-bound adenylate kinase (EC 2.7,4.3) as well as inorganic pyrophosphatase (EC 3.6.1.1) was detected in Zymomonas mobilis ATCC 29191. An increase in the molar growth yield (Y X/S ) of Z. mobilis under aerobic growth conditions appeared to be in proportion to a reduction of membrane-bound adenylate kinase (mAK) and ATPase activities and to an increase in cytoplasmic adenylate kinase (AK) activity. Significant (1 - P < 0.01) multiple regressions were observed between the values of Y x (dependent variable), ATPase and AK or AK and mAK as independent variables, suggesting that a combined operation of these phosphohydrolases and phosphotransferases would be…

IR-spectroscopic studies of Zymomonas mobilis and levan precipitate

2002

Abstract The mid-infrared (mid-IR) absorption spectra of Zymomonas mobilis 113 “S” bacterial biomass grown in sucrose or glucose medium, and levan precipitate in the fingerprint region were studied. IR-qualitative and quantitative analyses were carried out. The principal component concentration changes in Z. mobilis biomass at different growth phases showed that protein concentration was higher in case of glucose-based medium, but the total carbohydrate concentration was higher if grown in sucrose-based medium. Low concentration of intracellular carbohydrates was a characteristic parameter of levan-producing Z. mobilis cells. It was shown that during 2-month storage of Z. mobilis inoculum i…

Ethanol production improvement in Zymomonas mobilis by supplementation of fructan-cleaving enzymes on sucrose containing substrates

2010

Syntrophy of Crypthecodinium cohnii and immobilized Zymomonas mobilis for docosahexaenoic acid production from sucrose-containing substrates

2021

Marine heterotrophic dinoflagellate Crypthecodinium cohnii is an aerobic oleaginous microorganism that accumulates intracellular lipid with high content of 4,7,10,13,16,19-docosahexaenoic acid (DHA), a polyunsaturated ω-3 (22:6) fatty acid with multiple health benefits. C. cohnii can grow on glucose and ethanol, but not on sucrose or fructose. For conversion of sucrose-containing renewables to C. cohnii DHA, we investigated a syntrophic process, involving immobilized cells of ethanologenic bacterium Zymomonas mobilis for fermenting sucrose to ethanol. The non-respiring, NADH dehydrogenase-deficient Z. mobilis strain Zm6-ndh, with high ethanol yield both under anaerobic and aerobic condition…

The effect of osmo-induced stress on product formation by Zymomonas mobilis on sucrose

2000

The intensification of biosynthesis of fructooligosaccharides in the presence of high salt concentrations was observed during sucrose (10%) fermentation by Zymomonas mobilis 113S. A 0.6 M NaCl concentration led to an increase of oligosaccharide productivity by 3.5-fold. Sorbitol formation was increased in the presence of 0.16 M NaCl and was inhibited at highest salt concentrations. In a medium with high (65%, w/w) sucrose content the salts gave inhibitory effects on fructooligosaccharide production by lyophilised Z. mobilis cells. Influence of salts on gluconic acid and sorbitol formation under these conditions was studied. The ratio of oligosaccharides and gluconic acid productivity (Qolig…

FT-IR spectroscopic investigation of bacterial cell envelopes from Zymomonas mobilis which have different surface hydrophobicities

2013

Abstract Changes in the cell envelope composition of bacteria Zymomonas mobilis 113S which resulted in varied cell surface hydrophobicity (CSH) were examined using FT-IR-spectroscopy and conventional methods of biochemical analysis. Significant differences in all analyses were detected between hydrophilic and hydrophobic compounds in the envelopes of Z. mobilis . A significant positive linear relationship ( P Z. mobilis and the ratio of absorbance band intensities assigned to the CH 2 and CH 3 vibrations from lipids as well as the asymmetric and symmetric stretching vibrations of these methylene and methyl groups. Differences were also seen between the ratio of band absorbances arising from…