• Title/Summary/Keyword: Zymomonas mobilis

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Improvement of Process for Sorbitol Production with Cetyltrimethylammoniumbromide Permeabilized Cells of Zymomonas mobilis through Glutaraldehyde Crosslinking (Cetyltrimethylammoniumbromide로 투과성을 높힌 Zymomonas mobilis의 Glutaraldehyde Crosslinking에 의한 Sorbitol 생산 안정성의 향상)

  • 장기효;박철진전억한
    • KSBB Journal
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    • v.6 no.3
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    • pp.249-254
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    • 1991

  • Permeabilization of Zymomonas mobilis with CTAB(Cetyltrimethylammoniumbromide) was investigated in order to obtain stable process for sorbitol production in the immobilized system. The optimum conditions for sorbitol formation were obtained in the case of using cells treated with 0.2% CTAB at$ 4^{\circ}C$ for 10 min. Permeabilized cells were treated with glutaraldehyde to cross-link the internal enzyme for the improvement of the enzyme stability. In this way, no significant loss of enzyme activity was apparent during 30-day operation in a continuous process. The productivity of the continuous process at dilution rate 0.2h-1 was 6.51g/1/h for sorbitol. The CTAB permeabilized cells could be used to produce sorbitol in the long term continuous process.

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Ethanol Production from Raw Starch by Co-Immobilized Mixed Rhizopus japonicus and zymomonas mobilis (Rhizopus japonicus와 Zymomonas mobilis의 혼합고정화 배양계에 의한 생전분으로부터 에탄올 생산)

  • 최수철;이상원;박석규;성찬기;손봉수;성낙계
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.25 no.4
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    • pp.708-714
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    • 1996

  • Ethanol production from raw starch was performed using the co-immobilized culture system of Rhizopu japonicus and zymomonas mobilis(R-Z). Glucose Production in immobilized R. japonicus culture was 2-fold higher than that in free cell culture. Ethanol production was 1.67g/L(Yp/s, 0.094) and 6.549/L(Yp/s, 0.38) in R-Z and R-Z 24 culture system, respectively. R-Z system was modified and designated as R-Z 24 system by replacing cotton plug with silicon check valve after 24h fermentation with R-Z system. Optimal substrate concentration for ethanol production in batch culture was 5%(w/v) and ethanol concentration produced was 15.02g/L(Yp/s, 0.36). Ethanol yield(Yp/s, 0.38) in fed-batch culture of 5 times with 2%(w/v) substrate was equal to that in batch culture of 2%(w/v) substrate.

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Growth Characteristics of a Pyruvate Decarboxylase Mutant Strain of Zymomonas mobilis (Pyruvate decarboxylase 돌연변이 Zymomonas mobilis 균주의 생장 특성 연구)

  • Xun, Zhao;Peter L., Rogers;Kwon, Eilhann E.;Jeong, Sang Chul;Jeon, Young Jae
    • Journal of Life Science
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    • v.25 no.11
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    • pp.1290-1297
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    • 2015

  • Studies of the inactivation of a gene encoding pyruvate decarboxylase, pdc, in an ethanol-producing bacterium, Zymomonas mobilis, identified a mutant strain with 50% reduced PDC activity. To evaluate the possibility of a carbon-flux shift from an ethanol pathway toward higher value fermentation products, including pyruvate, succinate, and lactate, fermentation studies were carried out. Despite attempts to silence pdc expression in the wild-type strain ZM4 using cat-inserted pdc and pdc-deleted homologs by electroporation, the strain isolated showed partial gene activation. Fermentation experiments with the PDC mutant strain showed that the reduced expression level of PDC activity resulted in decreased rates of substrate uptake and ethanol production, together with increased pyruvate accumulation of 2.5 g l-1 , although lactate and succinate concentrations were not significantly enhanced in these modified strains. Despite numerous attempts, no strains were isolated in which complete pdc inactivation occurred. This result indicates that the ethanol fermentation pathway of this bacterium is totally dependent on the activity of the PDC enzyme. To ensure a redox balance of intracellular NAD and NADH levels, other enzymes, such as lactate dehydrogenase for lactate, and enzymes involved in the production of succinic acid, such as pyruvate dehydrogenase (PDH) and malic enzymes, may be needed for their increased end-product production.

  • https://doi.org/10.5352/JLS.2015.25.11.1290 인용 PDF KSCI KPUBS

Effect of Neupectin-L on Ethanol Production from Raw Starch Using a Co-Immobilized Aspergillus awamori and Zymomonas mobilis (Aspergillus awamori와 Zymomonas mobilis로 구성된 혼합고정화 배양계의 에탄올 생산에 미치는 Neupectin-L의 영향)

  • Lee, Sang-Won;Cho, Yong-Un;Kim, Hong-Chul;Park, Seok-Kyu;Sung, Nak-Kie
    • Applied Biological Chemistry
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    • v.40 no.2
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    • pp.89-94
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    • 1997

  • In order to reduce energy input in direct ethanol production from raw starch by co-immobilized Aspergillus awamori(A) and Zymomonas mobilis(Z), A-Z 36 culture system which was changed to anaerobic after 36 h of aerobic fermentation without sterilization was investigated. This immobilized cell system can not be carried out under unsterile conditions because of growth of microbial contaminants from original medium. Among some food additives such as sorbic acid, benzoic acid, dehydroacetic acid, p-hydroxybenzoic acid, Vantocil IB and Neupectin-L, Vantocil IB and Neupectin-L were a potent antibacterial agent in A-Z 36 culture cell system and were not affected in hydrolysis of substrate as compared with the case of control. Ethanol yield(6.9 g/l) in system of addition of 0.1% Neupectin-L was slightly higher than that in control(6.4 g/l). When 2% starch was fed five times in fed-batch culture with 0.1% Neupectin-L, ethanol yield and productivity were 34 g/l and 2.0 g/l/day, respectively.

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