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21.
Oh BR Seo JW Heo SY Hong WK Luo LH Son JH Park DH Kim CH 《Bioprocess and biosystems engineering》2012,35(1-2):159-165
We generated a genetically engineered Klebsiella pneumoniae strain (AK-VOT) to eliminate by-product formation during production of 1,3-propanediol (1,3-PD) from glycerol. In the present study, the glycerol-metabolizing properties of the recombinant strain were examined during fermentation in a 5 L bioreactor. As expected, by-product formation was completely absent (except for acetate) when the AK-VOT strain fermented glycerol. However, 1,3-PD productivity was severely reduced owing to a delay in cell growth attributable to a low rate of glycerol consumption. This problem was solved by establishing a two-stage process separating cell growth from 1,3-PD production. In addition, nutrient co-supplementation, especially with starch, significantly increased 1,3-PD production from glycerol during fed-batch fermentation by AK-VOT in the absence of by-product formation. 相似文献
22.
Sung-Mok Lee Baek-Rock Oh Jang Min Park Anna Yu Sun-Yeon Heo Won-Kyung Hong Jeong-Woo Seo Chul Ho Kim 《Biotechnology and Bioprocess Engineering》2013,18(6):1210-1215
To obtain high-yield production of 2,3-butanediol (2,3-BD) from glucose, we optimized the culture conditions for a lactate dehydrogenase-deficient mutant (ΔldhA) of Klebsiella pneumoniae using response surface methodology. 2,3-BD production was successfully improved by optimizing pH (5.6), aeration (3.50 vvm) and concentration of corn steep liquor (45.0 mL/L) as a nitrogen source, resulting in a maximum level of 2,3-BD production of 148.8 g/L and productivity of 2.48 g/L/h. 2,3-BD was also obtained with high concentration (76.24 g/L) and productivity (2.31 g/L/h) from the K. pneumoniae mutant strain using sugarcane molasses as a carbon source. 相似文献
23.
Oh BR Seo JW Heo SY Hong WK Luo LH Joe MH Park DH Kim CH 《Bioresource technology》2011,102(4):3918-3922
A mutant strain of Klebsiella pneumoniae, termed GEM167, was obtained by γ irradiation, in which glycerol metabolism was dramatically affected on exposure to γ rays. Levels of metabolites of the glycerol reductive pathway, 1,3-propanediol (1,3-PD) and 3-hydroxypropionic acid (3-HP), were decreased in the GEM167 strain compared to a control strain, whereas the levels of metabolites derived from the oxidative pathway, 2,3-butanediol (2,3-BD), ethanol, lactate, and succinate, were increased. Notably, ethanol production from glycerol was greatly enhanced upon fermentation by the mutant strain, to a maximum production level of 21.5 g/l, with a productivity of 0.93 g/l/h. Ethanol production level was further improved to 25.0 g/l upon overexpression of Zymomonas mobilispdc and adhII genes encoding pyruvate decarboxylase (Pdc) and aldehyde dehydrogenase (Adh), respectively in the mutant strain GEM167. 相似文献
24.
Won-Kyung Hong Anna Yu Sun-Yeon Heo Baek-Rock Oh Chul Ho Kim Jung-Hoon Sohn Ji-Won Yang Akihiko Kondo Jeong-Woo Seo 《Bioprocess and biosystems engineering》2013,36(7):959-963
The oleaginous microalga Aurantiochytrium sp. KRS101 was cultivated in enzymatic hydrolysates of alkali-pretreated empty palm fruit bunches (EFBs), without prior detoxification process. The maximal levels of lipid and docosahexaenoic acid synthesized were 12.5 and 5.4 g L?1 after cultivation for 36 h. Similar lipid levels were also obtained via simultaneous saccharification and cultivation. The results suggested that EFB is a promising source for production of useful lipids by the microalgal strain. 相似文献
25.
Sung-Mok Lee Won-Kyung Hong Sun-Yeon Heo Jang Min Park You Ree Jung Baek-Rock Oh Min-Ho Joe Jeong-Woo Seo Chul Ho Kim 《Journal of industrial microbiology & biotechnology》2014,41(8):1259-1266
The acetolactate synthase (als)-deficient mutant of Klebsiella pneumoniae fails to produce 1,3-propanediol (1,3-PD) or 2,3-butanediol (2,3-BD), and is defective in glycerol metabolism. In an effort to recover production of the industrially valuable 1,3-PD, we introduced the Zymomonas mobilis pyruvate decarboxylase (pdc) and aldehyde dehydrogenase (aldB) genes into the als-deficient mutant to activate the conversion of pyruvate to ethanol. Heterologous expression of pdc and aldB efficiently recovered glycerol metabolism in the 2,3-BD synthesis-defective mutant, enhancing the production of 1,3-PD by preventing the accumulation of pyruvate. Production of 1,3-PD in the pdc- and aldB-expressing als-deficient mutant was further enhanced by increasing the aeration rate. This system uses metabolic engineering to produce 1,3-PD while minimizing the generation of 2,3-BD, offering a breakthrough for the industrial production of 1,3-PD from crude glycerol. 相似文献
26.
The pduP gene encodes a propionaldehyde dehydrogenase (PduP) was investigated for the role in 3-hydroxypropionic acid (3-HP) glycerol metabolism in Klebsiella pneumoniae. The enzyme assay showed that cell extracts from a pduP mutant strain lacked measurable dehydrogenase activity. Additionally, the mutant strain accumulated the cytotoxic intermediate metabolite 3-hydroxypropionaldehyde (3-HPA), causing both cell death and a lower final 3-HP titer. Ectopic expression of pduP restored normal cell growth to mutant. The enzymatic property of recombinant protein from Escherichia coli was examined, exhibiting a broad substrate specificity, being active on 3-HPA. The present work is thus the first to demonstrate the role of PduP in glycerol metabolism and biosynthesis of 3-HP. 相似文献
27.
Lian Hua Luo Pil-Soo Seo Jeong-Woo Seo Sun-Yeon Heo Dae-Hyuk Kim Chul Ho Kim 《Biotechnology letters》2009,31(12):1867-1871
To investigate the effect of cellular fatty acids composition on ethanol tolerance in Escherichia coli, we overexpressed either des, encoding fatty acid desaturase from Bacillus subtilis, or fabA, encoding β-hydroxydecanoyl thio-ester dehydrase from E. coli, or both genes together, into E. coli. Recombinant E. coli harboring fabA had elevated tolerance against ethanol compared to wild type strain. In contrast, des decreased resistance to ethanol. Co-expression of both genes together complemented ethanol tolerance of E. coli. This result indicates how to engineer bacterial strains to be resistant to higher concentrations of ethanol. 相似文献
28.
Ju Jung-Hyun Oh Baek-Rock Heo Sun-Yeon Lee Young-Uk Shon Jung-hoon Kim Chul-Ho Kim Young-Min Seo Jeong-Woo Hong Won-Kyung 《Bioprocess and biosystems engineering》2020,43(1):33-43
Bioprocess and Biosystems Engineering - In this study, to produce adipic acid, mutant strains of Candida tropicalis KCTC 7212 deficient of AOX genes encoding acyl-CoA oxidases which are important... 相似文献