• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.256-259
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• 2000

Ethanol fermentration of glucose by a strain of Zymomonas mobilis KCTC 1535 was studied in membrane recycle bioreactor, which was coupled with closs flow hollow fiber membrane. The maximum values of product yields and productivity are 0.4685g total ethanol/ g glucose, 14.05g total ethanol/ L/h, respectively The pervaporation performance of the PDMS menbrane has been investigated for the separation of binary mixtures of EtOH/water at $50^{\circ}C{\sim}70^{\circ}C$. The optimum conditions of feed concentration, temperature, feed solution flow rates is determined to be 8%, $70^{\circ}C$, 492ml/min, respectively. An ethanol permselectivity of 7.5 and flux of $0.04kg/m^2/hr$ were obtained with these membrane

• Proceedings of the Korean Nutrition Society Conference
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• 2002.05a
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• pp.102-102
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• 2002

• Journal of Industrial Technology
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• v.29 no.B
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• pp.121-125
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• 2009

New cellulase genes, named as CelV2 and CelN1, respectively, were isolated from Erwinia carotovora ATCC15713 and expressed in E. coli. The CelV2 and CelN1 gene were PCR amplified with degenerated primers and PCR products were sequenced and expressed in E. coli. Two new cellulase genes showed 97% homologies with previously reported Erwinia cellulase genes. The recombinant cellulase were purified with Ni-NTA column chromatography and its enzymatic properties were characterized. The optimum temperature of two enzymes were about $50^{\circ}C$ degree and optimum pH were around pH7.0. The newly isolated celluase genes could be used for enhancing substrate range of alcohol-producing bacteria such as Zymomonas mobilis.

• The Korean Journal of Food And Nutrition
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• v.12 no.6
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• pp.559-563
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• 1999

Essential oil of Artemisia lavandulaefolia the chrysanthemum family plant used in the chinese medicine was extracted and antibacterial and antifungal activity with many kinds of the pathogenic bacterium and fungi was experimented by it. Ataphylococcus epidermidis and Streptococcus aureus gram positive bacterium at the concentration of 200ppm and Streptococcus mutans at the concentration of 1,000ppm showed the growth injibition effect of the cell. These showed statistically significant difference(p<0.05) Zymomonas mobilis Entrecoccus faecalis gram negative bacterium at the concentration of 200ppm and Pseudomonas putida at the concentration of 400ppm showedd the growth inhibition effect of the cell)p<0.05) V. Parahaemolyticus at the concentration of 800ppm and Pseudomonas aeruginosa at the concentration of 1,000ppm showed the growth inhibition effect of the cell(p<0.05) Candida albicans and Cryptococcus neoformans yeast-type fungi showed the gorwth inhibition effect of the cell at the concentration of 200ppm(p<0.05) Altenaria mali Aspergillus nidulans and Fusarium oxysporum filamentous fungi took the growth inhibition effect of the cell at the concentration of 600ppm, 400ppm, and 100ppm. respectively.

• Journal of Microbiology and Biotechnology
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• v.16 no.1
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• pp.102-108
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• 2006

The IscA gene, encoding a levansucrase of 424 amino acids (aa) residues, was cloned from the genomic DNA of Pseudomonas aurantiaca S-4380, and overexpressed in Escherichia coli. The recombinant levansucrase overexpressed in E. coli was then used to produce levan from sucrose. Levan crystals with 98% purity could be obtained from the reaction mixture with $62\%$ yield using an alcohol precipitation method. The molecular weight of the levan was $7\times10^5$ daltons. Methylation studies showed that the levan was branched: main linkage C-2,6; branched linkage C-2,1; and degree of branching $6\%$. Three bacterial levans from different strains were incubated with levan fructotransferase (LFTase) from Arthrobacter ureafaciens K2032, which produced $di-\beta-D-fructofuranose$ dianhydride IV (DFA IV); final conversion yields from the levans to DFA IV were $39\%$ in Zymomonas mobilis, $53\%$ in Serratia levanicum, and $59\%$ in P. aurantiaca S-4380 levansucrase. The levan from P. aurantiaca S-4380 levansucrase gave the highest conversion yield of levan to DFAIV so far reported.

• Journal of Microbiology and Biotechnology
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• v.18 no.7
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• pp.1257-1265
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• 2008

To lower the cost of ethanol distillation of fermentation broths, a high initial glucose concentration is desired. However, an increase in the substrate concentration typically reduces the ethanol yield because of insufficient mass and heat transfer. In addition, different operating temperatures are required to optimize the enzymatic hydrolysis (50$^{\circ}C$) and fermentation (30$^{\circ}C$). Thus, to overcome these incompatible temperatures, saccharification followed by fermentation (SFF) was employed with relatively high solid concentrations (10% to 20%) using a portion loading method. In this study, glucose and ethanol were produced from Solka Floc, which was first digested by enzymes at 50$^{\circ}C$ for 48 h, followed by fermentation. In this process, commercial enzymes were used in combination with a recombinant strain of Zymomonas mobilis (39679:pZB4L). The effects of the substrate concentration (10% to 20%, w/v) and reactor configuration were also investigated. In the first step, the enzyme reaction was achieved using 20 FPU/g cellulose at 50$^{\circ}C$ for 96 h. The fermentation was then performed at 30$^{\circ}C$ for 96 h. The enzymatic digestibility was 50.7%, 38.4%, and 29.4% after 96 h with a baffled Rushton impeller and initial solid concentration of 10%, 15%, and 20% (w/v), respectively, which was significantly higher than that obtained with a baffled marine impeller. The highest ethanol yield of 83.6%, 73.4%, and 21.8%, based on the theoretical amount of glucose, was obtained with a substrate concentration of 10%, 15%, and 20%, respectively, which also corresponded to 80.5%, 68.6%, and 19.1%, based on the theoretical amount of the cell biomass and soluble glucose present after 48 h of SFF.