• Journal of Microbiology and Biotechnology
• /
• 제2권2호
• /
• pp.115-121
• /
• 1992

In order to broaden the spectrum of substrate utilization of a Gram negative bacterium Zymomonas mobilis which has a great potential as an industrial ethanol producing microorganism, cloning of $\alpha$-amylase gene into Z. mobilis ZM4 was tried. The $\alpha$-amylase gene was isolated from Bacillus stearothermophilus. By Southern blot analysis, it was proven that the $\alpha$-amylase gene fragment was originated from a naturally occuring plasmid of B. stearothermophilus ATCC 31195. To place $\alpha$-amylase gene under the control of Z. mobilis promoter, two different Z. mobilis expression vectors, pZA26 and pLOI204, were used. The truncated $\alpha$-amylase gene was then introduced into these vectors. Both qualitative and quantitative activities of $\alpha$-amylase were observed in Z. mobilis cells harboring these plasmids with the $\alpha$-amylase gene inserted. Gas chromatographic analysis of ethanol showed that one of the Z. mobilis transconjugants was capable of producing 67 mM ethanol from rich medium(RM) containing 5% soluble starch as a sole carbon source.

• Journal of Microbiology and Biotechnology
• /
• 제20권1호
• /
• pp.94-100
• /
• 2010

Zymomonas mobilis was immobilized in a modified graphite felt cathode with neutral red (NR-cathode) and Saccharomyces cerevisiae was cultivated on a platinum plate anode. An electrochemical redox reaction was induced by 3 volts of electric potential charged to the cathode and anode. The Z. mobilis produced 1.3-1.5 M of ethanol in the cathode compartment, whereas the S. cerevisiae produced 1.7-1.9 M in the anode compartment after 96 h. The ethanol produced by the Z. mobilis immobilized in the NR-cathode and S. cerevisiae cultivated on the platinum plate was 1.5-1.6 times higher than that produced under conventional conditions. The electrochemical oxidation potential inhibited Z. mobilis, but activated S. cerevisiae. The SDS-PAGE pattern of the total soluble proteins extracted from the Z. mobilis cultivated under the electrochemical oxidation conditions was gradually simplified in proportion to the potential intensity. Z. mobilis and S. cerevisiae were cultivated in the cathode and anode compartments, respectively, of an electrochemical redox combination system. The Z. mobilis culture cultivated in the cathode compartment for 24 h was continuously transferred to the S. cerevisiae culture in the anode compartment at a rate of 300 ml/day. Approx. 1.0-1.2 M of ethanol was produced by the Z. mobilis in the cathode compartment within 24 h, and an additional 0.8-0.9 M produced by the S. cerevisiae in the anode compartment within another 24 h. Thus, a total of 2.0-2.1 M of ethanol was produced by the electrochemical redox combination of Z. mobilis and S. cerevisiae within 48 h.

• 한국식품과학회지
• /
• 제14권4호
• /
• pp.394-396
• /
• 1982

발효로부터 생성되는 에타놀에 의해서 균체성장속도가 제한되는 연속식 배양 시스템에서, 에타놀 생성균주인 Saccharomyces uvarum과 Zymomonas mobilisrks의 경쟁적 상호 작용을 연구한 결과 Zymomonas mobilis가 Saccharomyces uvarum에 비하여 에타놀에 대한 내성(耐性)이 크기 때문에 Zymomonas mobilis 만이 생존할 수 있다.

• 산업기술연구
• /
• 제29권B호
• /
• pp.115-119
• /
• 2009

Green fluorescent protein (GFPuv) was displayed on the surface of ethanol-producing bacteria Zymomonas mobilis using N-terminal domain of ice nucleation protein (INP) as an anchoring motif. To evaluate the ice nucleation protein as plausible anchor motif in Z. mobilis, GFPuv gene was subcloned into Zymomonas expression vector yielding pBBR1MCS-3/pPDC/INPN/GFPuv plasmid., INP-GFPuv fusion protein was expressed in Z. mobilis and its fluorescence was verified by confocal microscopy. The successful display of GFPuv on Zymomonas mobilis suggest that INP anchor motif could be used for future fusion partner in Z. mobilis strain improvement.

• Journal of Microbiology and Biotechnology
• /
• 제19권7호
• /
• pp.666-674
• /
• 2009

An electrochemical bioreactor (ECB) composed of a cathode compartment and an air anode was used in this study to characterize the ethanol fermentation of Zymomonas mobilis. The cathode and air anode were constructed of modified graphite felt with neutral red (NR) and a modified porous carbon plate with cellulose acetate and porous ceramic membrane, respectively. The air anode operates as a catalyst to generate protons and electrons from water. The growth and ethanol production of Z. mobilis were 50% higher in the ECB than were observed under anoxic nitrogen conditions. Ethanol production by growing cells and the crude enzyme of Z. mobilis were significantly lower under aerobic conditions than under other conditions. The growing cells and crude enzyme of Z. mobilis did not catalyze ethanol production from pyruvate and acetaldehyde. The membrane fraction of crude enzyme catalyzed ethanol production from glucose, but the soluble fraction did not. NADH was oxidized to $NAD^+$in association with $H_2O_2$reduction, via the catalysis of crude enzyme. Our results suggested that NADH/$NAD^+$balance may be a critical factor for ethanol production from glucose in the metabolism of Z. mobilis, and that the metabolic activity of both growing cells and crude enzyme for ethanol fermentation may be induced in the presence of glucose.

• 한국미생물·생명공학회지
• /
• 제15권5호
• /
• pp.319-327
• /
• 1987

알코올 생산성이 높은 Zymomonas 균주의 기질 이용성을 넓히기 위한 목적으로 natural replicon을 포함하며 적당한 항생제 저항표지를 갖는 plasmid vector의 제조를 시도하였다. Z. mobilis ATCC10988에서 분리된 몇 개의 plasmid중 3.9kb의 적당한 크기를 갖는 pZM3를 선정하여 수종의 제한효소로 처리하여 절편의 크기에 따라 유전자 지도를 작성하였다. pZM 3의 replicon과 pBR 325의 chloramphenicol 저항유전자를 포함한 재조합 plasmid인 pHZ22를 개발하고 이 plasmid vector가 숙주세포인 Z. mobilis ATCC31821에서 독립적으로 replication됨을 확인하였다. 또 하나의 항생제 저항표지로서 RP4의 tetracycline 저항유전자를 분리하여 pHZ22에 도입함으로써 pHZT224를 제조하였는데 이 plasmid vector도 Zymomonas로 conjugation에 의해 전이되어 안정하게 유지 되었다. 본 연구를 통하여 개발된 plasmid vector는 Z. mobilis와 E. coli에 공히 작용하는 shuttle vector 로서 외부 유전자를 Zymomonas에 도입시킬 수 있는 유용한 유전자 운반체임이 확인되었다.

• 한국식품영양과학회지
• /
• 제24권5호
• /
• pp.803-810
• /
• 1995

Gel bead의 효율적인 이용을 목적으로 산소요구성이 전혀 다른 두 균주로 구성된 혼합고정화 배양계의 개발을 시도하였다. 호기성 균으로서 A. awamori, 혐기성균으로서 Z. mobilis를 사용하여 생전분으로 부터 에탄올 생산을 행한 결과는 다음과 같다. 두 균주의 최적 혼합비율은 A. awamori $1.25{\times}10^{9}\;spore/L-gel$, Z. mobilis 0.5g cell/L-gel이었다. 배양이 완료된 후의 gel bead 내의 균주 분포는 각각 혐기부와 호기부, 즉 gel bead의 표면부와 중심부로 생육장소가 구분되어 있었다. A-Z계의 배양에서는 에탄올의 수율이 낮았고, 균사가 gel bead로 부터 누출되었다. 배양 개시 후 36시간째에 배양기의 면전을 특수 제조한 check valve가 부착된 실리콘 plug로 교환하여 혐기적 배양을 행한 A-Z 36계에서는 gel bead로 부터 균사의 누출이 상당히 억제되었고, pH가 4.3을 유지하면서, 에탄올의 수율이 대조구 보다 약2배 높게 나타났다.

• 한국미생물·생명공학회지
• /
• 제18권3호
• /
• pp.268-272
• /
• 1990

Zymomonas mobilis의 알코올 탈수소 효소 유전자가 클로닝된 대장균 형질전환체의 세포 추출물로부터 알코올 탈수소 효소를 분리정제하였다. 형질전환된 Escherichia coli(pADS93)가 생산하는 Z.mobilis 유전자 유래의 알코올 탈수소 효소는 분자량이 40,000인 동일한 4개의 subunits로 구성된 tetramer임이 밝혀졌으며 이것은 Z.mobilis의 세포 추출물로부터 분리한 알코올 탈수소 효소와 동일하였다. 이 효소의 정반응(ethanol 산화)은 pH의 영향을 많이 받으며 pH는 10.0이었고 역반응(acetaldehyde 환원)에서는 최적의 pH가 7.5-8.5 이었지만 pH에 따라 크게 영향을 받지는 않았다.

• 한국미생물·생명공학회지
• /
• 제17권4호
• /
• pp.301-306
• /
• 1989

Zymomonas mobilis ATCC 10988로부터 분리된 chromosomal DNA를 제한효소 Sau3Al으로 부분 절단한 후 이를 BamHI으로 완전 절단하여 alkaline phosphatase를 처치한 pUC9과 ligation하여 Escherichia coli JM83을 형질전환시키는데 사용하였다. 알코올 탈수소 효소활성을 나타내는_대장균 형질전환체를 선별하기 위해 allyl alcohol을 사용하였는데 이 때 allyl alcohol을 함유한 LB 한천 배지에서 자라지 못하는 두개의 clones을 얻었다. 이들 clones으로부터 분리한 plasmids를 여러가지 제한효소로 처리하여 agarose gel 전기영동으로 분석한 결과 2.6kb 크기의 동일한 DNA 조각을 공유하고 있음이 밝혀졌으며 이들 plasmids를 함유하고 있는 대장균 형질전환체와 Z. mobilis에서 생성된 효소를 각기 polyacrylamide gel 전기영동한 후 효소활성을 염색하고 또한 알코올 기질특이성을 조사한 결과 이들 plasmids 가 Z. mebilis 의 alcohol dehydrogenase II 유전자를 함유하고 있음이 밝혀졌다.

• Journal of Microbiology and Biotechnology
• /
• 제7권6호
• /
• pp.438-440
• /
• 1997

A continuous fermentation system employing immobilized cells of Zymomonas mobilis and Saccharomyces cerevisiae was studied for the mass production of ethanol. Ethanol production by cells immobilized with Ca-alginate was better than those by cells immobilized with K-carrageenan. Maximum ethanol production employing a continuous system by cells immobilized with Ca-alginate was 77.5 $g.l^{-1}h^{-1}$ at a dilution rate of 1.85 $h^{-1}$ with 82% conversion rate for Z. mobilis while that was 40.2 $g.l^{-1}h^{-1}$ at a dilution rate of 0.92 $h^{-1}$ with 85% conversion rate for S. cerevisiae. These results suggest that Ca-alginate is a better cell immobilization matrix than K-carrageenan and that immobilized cells of Z. mobilis are more efficient than S. cerevisiae for ethanol production.