• Journal of Microbiology and Biotechnology
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• v.4 no.2
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• pp.155-159
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• 1994

Two Zymomonas mobilis strains (ZM63 and ZM6307), containing both lactose and galactose operons, were constructed. $\beta$-Galactosidase and galactokinase assays indicated that both operons were expressed in both strains. The transport systems available for lactose uptake by Zymomonas mobilis were investigated using $^{14}C$-labelled lactose. After the outer membrane, which was considered to be a possible barrier to lactose uptake, was disrupted by treatment with EDTA and $Ca^{2+}$ ions, some increase in lactose uptake was observed in ZM6306 ($lac^+$) and ZM6307 ($lac^+\;gal^+$), but not in the parent, ZM6. This suggested that the outer membrane of Zymomonas mobilis acts as a barrier to lactose uptake to some degree, and also that the lactose permease is operational in Zymomonas mobilis.

• Korean Journal of Microbiology
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• v.23 no.1
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• pp.56-63
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• 1985

We have characterized the plasmids of zymomonas, and constructed E. coli-Zymomonas shuttle vector. Plasmids have been detected in four strains of Zymomonas mobilis. All strains tested had at least one plasmid ranging in size from about 1.7 to 46kb. Antibiotics resistances of Z. mobilis were tested to select the host strain. All strains were very sensitive to tetracycline and chloramphenicol. Homology tests between the plasmids in four strains showed that the plasmids of ATCC10988 is highly homologous to those of ZM1, and that there is no homology between plasmids of ZM4 and Agll. The 1.7kb plasmid of ATCC10988, named as pZM886, also has no homology with plasmids of ZM4. A hybrid plasmid, designated to pBZ41, was constructed from pZM886 and pBR322. A restriction map of pBZ41 was established. Replicon of pZM886 didn't operate in E.coli and pBR322 seemed not to replicate in Zymomonas. pBZ41 was transfered from E. coli to Zymomonas by conjugal mobilization. The transconjugants were resistant to tetracycline and maintained pBZ41 stably.

• Journal of Microbiology and Biotechnology
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• v.2 no.2
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• pp.115-121
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• 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
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• v.13 no.1
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• pp.90-98
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• 2003

In vivo $^31p$ Nuclear Magnetic Resonance ($^31p$NMR) and metabolic studies were carried out on an acetic acid tolerant mutant, Zymomonas mobilis $ZM4/Ac^R$, and compared to those of the parent strain, Z. mobilis ZM4, to evaluate possible mechanisms of acetic acid resistance. This investigation was initiated to determine whether or not the mutant strain might be used as a suitable recombinant host far ethanol production from lignocellulose hydrolysates containing various inhibitory compounds. $ZM4/Ac^R$ showed multiple resistance to other lignocellulosic toxic compounds such as syringaldehyde, furfural, hydroxymethyl furfural, vanillin, and vanillic acid. The mutant strain was resistant to higher concentrations of ethanol or lower pH in the presence of sodium acetate, compared to ZM4 which showed more additive inhibition. in vivo $^31p$ NMR studies revealed that intracellular acidification and de-energization were two mechanisms by which acetic acid exerted its inhibitory effect. For $ZM4/Ac^R$, the internal pH and the energy status were less affected by sodium acetate compared to the parent strain. This resistance to pH change and de-energization caused by acetic acid is a possible explanation for the development of resistance by this strain.

• Genomics & Informatics
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• v.2 no.4
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• pp.184-190
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• 2004

An approach for genome analysis based on assembly of fragments of DNA from the whole genome can be applied to obtain the complete nucleotide sequence of the genome of Zymomonas mobilis. However, the problem of fragment assembly raise thorny computational issues. Computer simulation studies of sequence assembly usually show some abnormal assemblage of artificial sequences containing repetitive or duplicated regions, and suggest methods to correct those abnormalities. In this paper, we describe five simulation studies which had been performed previous to the actual genome assembly process of Zymomonas mobilis ZM4.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.309-315
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• 1998

An extracellular levansucrase, which catalyzes the formation of levan from sucrose, from the culture broth of Zymomonas mobilis ZM1 was purified by conventional column purification methods. The final purification yield was 18.3 fold of the crude enzyme from Z. mobilis, with 16.5 % of the enzyme recovered in the preparation step. The molecular weight of the enzyme was estimated to be 91,000 by Superose 12 gel filtration, and 45,000 by SDS-PAGE, indicating that levansucrase is a dimer. The optimum pH for the enzyme activity was around pH 4.0 for sucrose hydrolysis, and was around pH 5.0 for levan formation. The enzyme was inhibited by some metal ions, such as Hg$\^$2+/ and Cu2$\^$2+/, and 50% of inhibition was observed with 5mM EDTA. The enzyme activity was enhanced by the presence of detergent Triton X-100, but inhibited by SDS completely The enzyme catalyzes the liberation of reducing sugars, oligosacccharides and the formation of fructose polymer(levan). The enzyme also catalyzes the transfructosylation reaction of fructose moiety from sucrose to various sugar acceptor molecules, including sugar alcohols.

• Microbiology and Biotechnology Letters
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• v.15 no.5
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• pp.319-327
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• 1987

In order to develop useful plasmid vectors for Zymomonas cells, attempts were made to isolate natural plasmids from Z. mobilis ATCC10988. Among a few plasmids isolated, a small plasmid of 3.9 Kb size was chosen and designated as pZM3. By introducing the replication origin of pZM3 into pBR325, a hybrid plasmid vector of 8.4 Kb size, pHZ22, was constructed. This vector contained chloramphenicol resistant gene as a selectable marker and proved to be conjugally transmissible and stably maintained in Z. mobilis. Tetracycline resistant gene was isolated from RP4 and introduced into pHZ22 to make a new vector called pHZT224 of 10.7 Kb size. Through n series of experiments, it was evident that these plasmid vectors containing selectable markers of chloramphenicol and tetracycline resistance were shuttle vectors functional in Z. mobilis as well as E. coli.

• Proceedings of the Microbiological Society of Korea Conference
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• 2005.05a
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• pp.85-85
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• 2005

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.94-94
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• 1995

No Abstract, See Full Text

• Proceedings of the Microbiological Society of Korea Conference
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• 1999.04a
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• pp.47.2-47.2
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• 1999