Lian Hua Luo
Chonbuk National University
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Featured researches published by Lian Hua Luo.
Bioresource Technology | 2011
Baek-Rock Oh; Jeong-Woo Seo; Sun-Yeon Heo; Won-Kyung Hong; Lian Hua Luo; Min-ho Joe; Don-Hee Park; Chul Ho Kim
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 mobilis pdc and adhII genes encoding pyruvate decarboxylase (Pdc) and aldehyde dehydrogenase (Adh), respectively in the mutant strain GEM167.
Bioresource Technology | 2012
Lian Hua Luo; Chul Ho Kim; Sun-Yeon Heo; Baek-Rock Oh; Won-Kyung Hong; Seonghun Kim; Dae-Hyuk Kim; Jeong-Woo Seo
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.
Biotechnology Letters | 2009
Lian Hua Luo; Pil-Soo Seo; Jeong-Woo Seo; Sun-Yeon Heo; Dae-Hyuk Kim; Chul Ho Kim
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.
Applied Microbiology and Biotechnology | 2010
Jeong-Woo Seo; Mi-Young Seo; Baek-Rock Oh; Sun-Yeon Heo; Jin-Oh Baek; Dina Rairakhwada; Lian Hua Luo; Won-Kyung Hong; Chul Ho Kim
In a previous study, we showed that 1,3-propanediol (1,3-PD) was still produced from glycerol by the Klebsiella pneumoniae mutant strain defective in 1,3-PD oxidoreductase (DhaT), although the production level was lower compared to the parent strain. As a potential candidate for another putative 1,3-PD oxidoreductase, we identified and characterized a homolog of Escherichia coli yqhD (88% homology in amino acid sequence), which encodes an alcohol dehydrogenase and is well known to replace the function of DhaT in E. coli. Introduction of multiple copies of the yqhD homolog restored 1,3-PD production in the mutant K. pneumoniae strain defective in DhaT. In addition, by-product formation was still eliminated in the recombinant strain due to the elimination of the glycerol oxidative pathway. An increase in NADP-dependent 1,3-PD oxidoreductase activity was observed in the recombinant strain harboring multiple copies of the yqhD homolog. The level of 1,3-PD production during batch fermentation in the recombinant strain was comparable to that of the parent strain; further engineering can generate an industrial strain producing 1,3-propanediol.
Bioresource Technology | 2013
Baek-Rock Oh; Won-Kyung Hong; Sun-Yeon Heo; Lian Hua Luo; Akihiko Kondo; Jeong-Woo Seo; Chul Ho Kim
In the present study, mutant strain of Klebsiella pneumoniae with deletion of the crr gene encoding EIIA(Glc) (a component of the glucose-specific phosphoenolpyruvate-dependent transferase system [PTS]) was prepared. This eliminated the ability of the strain to mediate carbon catabolite repression (CCR). Production of 1,3-propanediol (1,3-PD) from glycerol by the crr mutant strain was enhanced (compared to that of the parent) in the presence of glucose. Using molasses as a co-substrate of glycerol, the maximum yield of 1,3-PD was 60.4% greater (81.2g/l) than that obtained when glycerol was used alone, under optimum fermentation conditions.
Bioprocess and Biosystems Engineering | 2013
Baek-Rock Oh; Jeong-Woo Seo; Sun-Yeon Heo; Lian Hua Luo; Won-Kyung Hong; Don-Hee Park; Chul-Ho Kim
In the present study, we developed an efficient method of 1,3-propanediol (1,3-PD) production from glycerol by genetic engineering of Klebsiella pneumoniae AK mutant strains. The proposed approach eliminated by-product formation and IPTG induction resulted in maximal production of 1,3-PD. A series of recombinant strains was designed to constitutively express the dhaB and/or dhaT genes, using the bacteriophage T5 PDE20 promoter and the rho-independent transcription termination signal of the Rahnella aquatilis levansucrase gene. Among these strains, AK/pConT expressing dhaT alone gave the highest yield of 1,3-PD. Fed-batch fermentation resulted in efficient production of 1,3-PD from either pure or crude glycerol, without by-product formation.
Applied Microbiology and Biotechnology | 2011
Lian Hua Luo; Jeong-Woo Seo; Jin-Oh Baek; Baek-Rock Oh; Sun-Yeon Heo; Won-Kyung Hong; Dae-Hyuk Kim; Chul Ho Kim
Biotechnology Letters | 2010
Won-Kyung Hong; Chul-Ho Kim; Sun-Yeon Heo; Lian Hua Luo; Baek-Rock Oh; Jeong-Woo Seo
Journal of Industrial Microbiology & Biotechnology | 2011
Lian Hua Luo; Jeong-Woo Seo; Baek-Rock Oh; Pil-Soo Seo; Sun-Yeon Heo; Won-Kyung Hong; Dae-Hyuk Kim; Chul Ho Kim
Applied Biochemistry and Biotechnology | 2012
Baek-Rock Oh; Jeong-Woo Seo; Sun-Yeon Heo; Won-Kyung Hong; Lian Hua Luo; Seonghun Kim; Don-Hee Park; Chul Ho Kim
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Korea Research Institute of Bioscience and Biotechnology
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