Engineering electron metabolism to increase ethanol production in Clostridium thermocellum
메타 데이터
바이오화학분류
바이오플라스틱
플라스틱
바이오정밀화학
용매
화학제품
연료
화장품용 기능성소재
계면활성제⁄증점제
의료용 화학소재
식품첨가제
논문
Engineering electron metabolism to increase ethanol production in Clostridium thermocellum
학술지
Metabolic engineering
저자명
Lo, Jonathan; Olson, Daniel G.; Murphy, Sean Jean-Loup; Tian, Liang; Hon, Shuen; Lanahan, Anthony; Guss, Adam M.; Lynd, Lee R.
초록
<P><B>Abstract</B></P> <P>The NfnAB (NADH-dependent reduced ferredoxin: NADP<SUP>+</SUP> oxidoreductase) and Rnf (ion-translocating reduced ferredoxin: NAD<SUP>+</SUP> oxidoreductase) complexes are thought to catalyze electron transfer between reduced ferredoxin and NAD(P)<SUP>+</SUP>. Efficient electron flux is critical for engineering fuel production pathways, but little is known about the relative importance of these enzymes in vivo. In this study we investigate the importance of the NfnAB and Rnf complexes in <I>Clostridium thermocellum</I> for growth on cellobiose and Avicel using gene deletion, enzyme assays, and fermentation product analysis. The NfnAB complex does not seem to play a major role in metabolism, since deletion of <I>nfnAB</I> genes had little effect on the distribution of fermentation products. By contrast, the Rnf complex appears to play an important role in ethanol formation. Deletion of <I>rnf</I> genes resulted in a decrease in ethanol formation. Overexpression of <I>rnf</I> genes resulted in an increase in ethanol production of about 30%, but only in strains where the <I>hydG</I> hydrogenase maturation gene was also deleted.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The <I>nfnAB</I> operon does not seem to play a role in <I>C. thermocellum</I> metabolism. </LI> <LI> The <I>rnf</I> operon is important for ethanol production. </LI> <LI> Overexpression of <I>rnf</I> increased ethanol production in certain strains. </LI> <LI> Electron transfer from ferredoxin to NAD<SUP>+</SUP> is critical to increasing biofuel yield. </LI> </UL> </P>