• KSBB Journal
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• v.23 no.5
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• pp.413-418
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• 2008

The production of 1,3.propanediol (1,3-PD) was investigated with Klebsiella pneumoniae DSM2026 and K. pneumoniae DSM4799 using crude glycerol obtained from biodiesel industry. Crude glycerol was used without prior purification to investigate effects of impurities in crude glycerol on 1,3-PD production. In the batch cultures, 1,3-PD production with crude glycerol was $1.1{\sim}2.5$ times higher than that with pure glycerol, indicating that crude glycerol is even a better substrate than pure glycerol for 1,3-PD fermentation. When glucose was added, 1,3-PD production and yield decreased in spite of enhanced cell growth. Furthermore, the addition of glucose was found to increase 2,3-butanediol, a by-product, significantly because of the change in metabolism in the presence of glucose. In semi-batch cultures without glucose addition, 26 g/L 1,3-PD was produced with crude glycerol, which was $2{\sim}3$ times higher than that with pure glycerol. Based on our results, it was clearly shown that crude glycerol is an effective substrate for biological 1,3-PD production, making it more feasible to produce 1,3-PD at a lower price.

• Journal of Life Science
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• v.6 no.3
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• pp.171-177
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• 1996

It was carried out to find the carbohydrate metabolism for the glycogen utilization and the effects of low temperature(1$\circ$C, 5$\circ$C)on embryonic development of the silkworm, Bombyx mori L. The content of sorbitol and glycerol in the chillihg eggs stored at 5$\circ$C or 1$\circ$C on 24 hours after oviposition showed the highest level on the 50th day. After that, the corresponding value in the eggs stored at 5$\circ$C were decreased, and the value in the eggs stored at 1$\circ$C maintained the similar level. The trehalose level was rapidly increased on 50$\sim$60th day or thereabouts, and then, it was accumulated. When the eggs stored at low temperature were tranaferred and developed the embryo at 25$\circ$C, sorbitol and glycerol were respectively changed to glycogen. Futhemore, the content of trehalose and glucose showed specific of patterns with each embryonic stage at low temperature. With the aforementioned results, the intemediary metabolism of carbohydrate was discussed with regard to embryonic development of non-diapause eggs of silkworms.

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.429-438
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• 2021

Bacterial cellulose (BC) is widely used in the food industry for products such as nata de coco. The mechanical properties of BC hydrogels, including stiffness and viscoelasticity, are determined by the hydrated fibril network. Generally, Komagataeibacter bacteria produce gluconic acids in a glucose medium, which may affect the pH, structure and mechanical properties of BC. In this work, the effect of pH buffer on the yields of Komagataeibacter hansenii strain ATCC 53582 was studied. The bacterium in a phosphate and phthalate buffer with low ionic strength produced a good BC yield (5.16 and 4.63 g/l respectively), but there was a substantial reduction in pH due to the accumulation of gluconic acid. However, the addition of gluconic acid enhanced the polymer density and mechanical properties of BC hydrogels. The effect was similar to that of the bacteria using glycerol in another carbon metabolism circuit, which provided good pH stability and a higher conversion rate of carbon. This study may broaden the understanding of how carbon sources affect BC biosynthesis.

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1439-1444
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• 2008

The recombinant E. coli $\Delta$6 mutant (galR, glpK, gldA, IdhA, lacI, tpiA) was used to produce 1,3-propanediol (PD) from glucose. The 1,3-PD production increased with feedback control of the glucose concentration using fed-batch fermentation. The maximum 1,3-PD concentration produced was 43 g/l after 60 h of fermentation. Glycerol production was minimized when controlling the glucose concentration at less than 1 g/l. The expression levels of seven enzymes related to the 1,3-PD production metabolism were compared during the cell growth phase and 1,3-PD production phase, and their expression levels all increased during 1,3-PD production, with the exception of alcohol dehydrogenase.

• Journal of Microbiology and Biotechnology
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• v.17 no.2
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• pp.244-252
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• 2007

Escherichia coli has a PhoR-PhoB two-component regulatory system to detect and respond to the changes of environmental phosphate concentration. For the E. coli W3110 strain growing under phosphate-limiting condition, the changes of global gene expression levels were investigated by using DNA microarray analysis. The expression levels of some genes that are involved in phosphate metabolism were increased as phosphate became limited, whereas those of the genes involved in ribosomal protein or amino acid metabolism were decreased, owing to the stationary phase response. The upregulated genes could be divided into temporarily and permanently inducible genes by phosphate starvation. At the peak point showing the highest expression levels of the phoB and phoR genes under phosphate-limiting condition, the phoB- and/or phoR-dependent regulatory mechanisms were investigated in detail by comparing the gene expression levels among the wild-type and phoB and/or phoR mutant strains. Overall, the phoB mutation was epistatic over the phoR mutation. It was found that PhoBR and PhoB were responsible for the upregulation of the phosphonate or glycerol phosphate metabolism and high-affinity phosphate transport system, respectively. These results show the complex regulation by the PhoR-PhoB two-component regulatory system in E. coli.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.1
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• pp.127-134
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• 2015

Castration induces the accumulation of body fat and deposition of intramuscular fat in Korean cattle, resulting in improved beef quality. However, little is known about the metabolic adaptations in the liver following castration. To understand changes in lipid metabolism following castration, hepatic expression levels of lipid metabolism genes were compared between Korean bulls and steers. Steers had higher (p<0.001) hepatic lipids contents and higher (p<0.01) mRNA levels of lipogenic acetyl-CoA carboxylase. This differential gene expression may, in part, contribute to increased hepatic lipid content following the castration of bulls. However, we found no differences in the hepatic expression levels of genes related to triglyceride synthesis (mitochondrial glycerol-3-phosphate acyltransferase, diacylglycerol O-acyltransferase 1 and 2) and fatty acid (FA) oxidation (carnitine palmitoyltransferase 1A, C-4 to C-12 straight chain acyl-CoA dehydrogenase, very long chain acyl-CoA dehydrogenase) between bulls and steers. No differences in gene expression for very-low-density lipoprotein (VLDL) secretion, including apolipoprotein B mRNA and microsomal triglyceride transfer protein (MTTP) protein, were observed in the liver although MTTP mRNA levels were higher in steers compared to bulls. In conclusion, FA synthesis may contribute to increased hepatic lipid deposition in steers following castration. However, hepatic lipid metabolism, including triglyceride synthesis, FA oxidation, and VLDL secretion, was not significantly altered by castration. Our results suggest that hepatic lipid metabolism does not significantly contribute to increased body fat deposition in steers following castration.

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

• Molecules and Cells
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• v.22 no.2
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• pp.239-245
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• 2006

This study examined whether adult bovine muscle satellite cells from 30-month-old Hanwoo cattle are multipotential. The satellite cells were found to have the potential to proliferate and differentiate into myoblasts with the formation of multinucleated cells. In addition, treatment with the peroxisome proliferator activating receptor-${\gamma}$ ($PPAR{\gamma}$) agonist, rosiglitazone, promoted their trans-differentiation into adipocytes with significant increases in glycerol accumulation and glycerol-3-phosphate dehydrogenase activity. Western blot analysis revealed that increased levels of the adipocyte fatty acid-binding protein, $PPAR{\gamma}$ and of CCAAT/enhancerbinding protein were closely related to rosiglitazoneinduced differentiation of the cells. These findings demonstrate that satellite cells from adult Hanwoo cattle are multipotent, and that their trans-differentiation into adipocytes can be induced by rosiglitazone.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.628-635
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• 2002

Five terpenes (1~5), three fatty acids (6~8), two sterols (9 and 11), and a monogalactosyldiacyl glycerol (10) were isolated from the methylene chloride extract of the aerial part of Cirsium setidens. Their chemical structures were determined to be $\alpha$-tocopherol (1), 25-hydroperoxycycloart-23-en-3$\beta$-o1 (2), 24-hydroperoxycycloart-25-en-3$\beta$-o1 (3), mokko lactone (4), transphytol (5), 9, 12, 15-octadecatrienoic acid (6), 9, 12-octadecadienoic acid (7), hexadecanoic acid (8), acylglycosyl $\beta$-sitosterol (9), (2R)-1, 2-O-(9z, 12z, 15z-dioctadecatrienoyl)-3-O-$\beta$-D-galactopyranosyl glycerol (10) and $\beta$-sitosterol glucoside (11) by spectral evidences. Compound 3 exhibited significant cytotoxic activity against five human cancer cell lines with its $ED_{50}$ values ranging from 2.66 to 11.25 $\mu$M.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.753-761
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• 2020

To determine the role of pyruvate dehydrogenase complex (PDHC) in Klebsiella pneumoniae, the growth and metabolism of PDHC-deficient mutant in glycerol-based medium were analyzed and compared with those of other strains. Under aerobic conditions, the PDHC activity was fourfold higher than that of pyruvate formate lyase (PFL), and blocking of PDHC caused severe growth defect and pyruvate accumulation, indicating that the carbon flux through pyruvate to acetyl coenzyme A mainly depended on PDHC. Under anaerobic conditions, although the PDHC activity was only 50% of that of PFL, blocking of PDHC resulted in more growth defect than blocking of PFL. Subsequently, combined with the requirement of CO₂ and intracellular redox status, it was presumed that the critical role of PDHC was to provide NADH for the anaerobic growth of K. pneumoniae. This presumption was confirmed in the PDHC-deficient mutant by further blocking one of the formate dehydrogenases, FdnGHI. Besides, based on our data, it can also be suggested that an improvement in the carbon flux in the PFL-deficient mutant could be an effective strategy to construct high-yielding 1,3-propanediol-producing K. pneumoniae strain.