• Journal of Microbiology and Biotechnology
• /
• v.28 no.2
• /
• pp.293-297
• /
• 2018

Controlling the residual glucose concentration is important for improving productivity in $\text\tiny{L}$-threonine fermentation. In this study, we developed a procedure to automatically control the feeding quantity of glucose solution as a function of ammonia-water consumption rate. The feeding ratio ($R_{C/N}$) of glucose and ammonia water was predetermined via a stoichiometric approach, on the basis of glucose-ammonia water consumption rates. In a 5-L fermenter, 102 g/l $\text\tiny{L}$-threonine was obtained using our glucose-ammonia water combined feeding strategy, which was then successfully applied in a 500-L fermenter (89 g/l). Therefore, we conclude that an automatic combination feeding strategy is suitable for improving $\text\tiny{L}$-threonine production.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.4
• /
• pp.571-578
• /
• 2018

Biofuel production using lignocellulosic biomass is gaining attention because it can be substituted for fossil fuels without competing with edible resources. However, because Saccharomyces cerevisiae does not have a ${\text\tiny{D}}$-xylose metabolic pathway, oxidoreductase or isomerase pathways must be introduced to utilize ${\text\tiny{D}}$-xylose from lignocellulosic biomass in S. cerevisiae. To elucidate the biochemical properties of xylose isomerase (XI) from Piromyces sp. E2 (PsXI), we determine its crystal structure in complex with substrate mimic glycerol. An amino-acid sequence comparison with other reported XIs and relative activity measurements using five kinds of divalent metal ions confirmed that PsXI belongs to class II XIs. Moreover kinetic analysis of PsXI was also performed using $Mn^{2+}$, the preferred divalent metal ion for PsXI. In addition, the substrate-binding mode of PsXI could be predicted with the substrate mimic glycerol bound to the active site. These studies may provide structural information to enhance ${\text\tiny{D}}$-xylose utilization for biofuel production.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.7
• /
• pp.1061-1070
• /
• 2019

In the present study, the optimization of poly(${\gamma}$-glutamic acid) (${\gamma}$-PGA) production by Bacillus sp. FBL-2 was studied using a statistical approach. One-factor-at-a-time method was used to investigate the effect of carbon sources and nitrogen sources on ${\gamma}$-PGA production and was utilized to select the most significant nutrients affecting the yield of ${\gamma}$-PGA. After identifying effective nutrients, response surface methodology with central composite design (CCD) was used to obtain a mathematical model to identify the optimum concentrations of the key nutrients (sucrose, $\text\tiny{L}$-glutamic acid, yeast extract, and citric acid) for improvement of ${\gamma}$-PGA production. The optimum amount of significant medium components appeared to be sucrose 51.73 g/l, $\text\tiny{L}$-glutamic acid 105.30 g/l, yeast extract 13.25 g/l, and citric acid 10.04 g/l. The optimized medium was validated experimentally, and ${\gamma}$-PGA production increased significantly from 3.59 g/l (0.33 g/l/h) to 44.04 g/l (3.67 g/l/h) when strain FBL-2 was cultivated under the optimal medium developed by the statistical approach, as compared to non-optimized medium.

• Proceedings of the Plant Resources Society of Korea Conference
• /
• 2007.11a
• /
• pp.328.2-328.2
• /
• 2007

See Full Text

• Journal of the Korea Convergence Society
• /
• v.9 no.7
• /
• pp.155-162
• /
• 2018

This study explores the relationship between images and texts through advertising production using images and texts, and analyzes the student works with the semiotics of Roland Barth. Since Barth emphasized the interpreter's interpretation rather than the producer's intention in his work, he interpreted the work as a receiver. It was analyzed in terms of socio-cultural meaning of what students produced in the works. A total of 64 classes were held for the first two classes in D high school. The results of analyzing students' works after the advertisement production class are as follows. First, as a result of analyzing Barth 's myth structure model, advertisement image and text are symbols and have meaning. Second, advertising image and text complement each other and have the characteristic of interrelationship that constitutes meaning. Third, By attracting the socio-cultural implications inherent in the students' advertising, their values and interests could be discovered.

• Proceedings of the Zoological Society Korea Conference
• /
• 1998.10b
• /
• pp.217.2-217
• /
• 1998

No Abstract, See Full Text

• The Plant Pathology Journal
• /
• v.16 no.2
• /
• pp.90-97
• /
• 2000

No Abstract.See Full-text

• Proceedings of the Zoological Society Korea Conference
• /
• 1995.10b
• /
• pp.355.1-355
• /
• 1995

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 1997.10b
• /
• pp.308.2-308
• /
• 1997

No Abstract, See Full Text

• Proceedings of the Zoological Society Korea Conference
• /
• 1997.10b
• /
• pp.74-74
• /
• 1997

No Abstract, See Full Text