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Metabolic engineering of <i>Enterobacter aerogenes</i> to improve the production of 2,3-butanediol
Thapa, Laxmi Prasad,Lee, Sang Jun,Park, Chulhwan,Kim, Seung Wook Elsevier 2019 Biochemical engineering journal Vol.143 No.-
<P><B>Abstract</B></P> <P>The enhanced production of 2,3-butanediol was investigated using a metabolic engineering approach and optimized fermentation conditions. New engineered strains of <I>Enterobacter aerogenes</I> ATCC 29007 were developed by deleting the <SMALL>D</SMALL>-<I>lactate dehydrogenase</I> (<I>ldh</I>A), <I>phosphate acetyltransferase</I> (<I>pta</I>), <I>malate dehydrogenase</I> (<I>mdh</I>), and <I>acetaldehyde dehydrogenase</I> (<I>acdh</I>) genes to block the production of lactate, acetate, succinate, and ethanol, respectively. The resulting engineered strain <I>E. aerogenes</I> SUMI02 (Δ<I>ldh</I>AΔ<I>pta</I>) produced 36.5 g/L of 2,3-butanediol in flask cultivation, an amount 8.11 times greater than that of its wild type counterpart (4.5 g/L). In addition, the 2,3-butanediol production and productivity reached 38.24 g/L and 0.8 g/L/h, respectively, in the batch fermentation using a bioreactor.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>Pta, ladhA, mdh and acdh</I> genes were successfully deleted in <I>E. aerogenes</I> ATCC 29007. </LI> <LI> Glucose was used as a carbon source by <I>E. aerogenes</I> to produce 2, 3-butanediol. </LI> <LI> <I>E. aerogenes</I> SUMI02 produced two fold higher 2, 3-butanediol than wild strain. </LI> <LI> Deletion of <I>pta</I> gene increased lactate production but reduced other metabolites. </LI> <LI> By deletion of <I>ldh</I>A and <I>pta</I> genes, 2, 3-butanediol production was maximized. </LI> </UL> </P>
Seungwook Kim,Han Suk Choi,Dong Sup kim,Laxmi Prasad Thapa,Sang Jun Lee,Sung Bong Kim,Jaehoon Cho,박철환 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.12
The enzyme cellobiose dehydrogenase (CDH), with high ability of electron transport, has been widely used in enzymatic fuel cells or biosensors. In this study, the cellobiose dehydrogenase gene from Phanerochaete chrysosporium KCCM 60256 was amplified and expressed in the methylotrophic yeast Pichia pastoris X-33. The recombinant enzyme (PcCDH) was purified using a metal affinity chromatography under non-denaturing conditions. The purified enzyme was analyzed by SDS-PAGE, confirming a corresponding band about 100 kDa. The enzyme activity of this purified PcCDH was determined as 1,845U/L (65mg/L protein). The enzyme showed the maximum activity at pH 4.5 and high activity in broad ranges of temperature from 30 oC to 60 oC. Moreover, the application of PcCDH to enzymatic fuel cell (EFC) was demonstrated. Lactose was used as the substrate in the EFC system; anode and cathode were immobilized with PcCDH and laccase, respectively. The cell’s open circuit voltage and maximum power density of the EFC system were, respectively, determined as 0.435 V and 314 μW/cm2 (at 0.247 V) with 10 mM lactose.