BioChem - DOS

Engineering furfural tolerance in Escherichia coli improves the fermentation of lignocellulosic sugars into renewable chemicals

Proceedings of the National Academy of Sciences of the United States of America

Wang, Xuan; Yomano, Lorraine P.; Lee, James Y.; York, Sean W.; Zheng, Huabao; Mullinnix, Michael T.; Shanmugam, K. T.; Ingram, Lonnie O.

<P>Pretreatments such as dilute acid at elevated temperature are effective for the hydrolysis of pentose polymers in hemicellulose and also increase the access of enzymes to cellulose fibers. However, the fermentation of resulting syrups is hindered by minor reaction products such as furfural from pentose dehydration. To mitigate this problem, four genetic traits have been identified that increase furfural tolerance in ethanol-producing <I>Escherichia coli</I> LY180 (strain W derivative): increased expression of <I>fucO</I>, <I>ucpA</I>, or <I>pntAB</I> and deletion of <I>yqhD</I>. Plasmids and integrated strains were used to characterize epistatic interactions among traits and to identify the most effective combinations. Furfural resistance traits were subsequently integrated into the chromosome of LY180 to construct strain XW129 (LY180 &#x0394;<I>yqhD ackA::</I>P<SUB><I>yadC</I>&#x2032;</SUB><I>fucO-ucpA</I>) for ethanol. This same combination of traits was also constructed in succinate biocatalysts (<I>Escherichia coli</I> strain C derivatives) and found to increase furfural tolerance. Strains engineered for resistance to furfural were also more resistant to the mixture of inhibitors in hemicellulose hydrolysates, confirming the importance of furfural as an inhibitory component. With resistant biocatalysts, product yields (ethanol and succinate) from hemicellulose syrups were equal to control fermentations in laboratory media without inhibitors. The combination of genetic traits identified for the production of ethanol (strain W derivative) and succinate (strain C derivative) may prove useful for other renewable chemicals from lignocellulosic sugars.</P>

2013

National Academy of Sciences

0027-8424

1091-6490

110

10

pp.4021-4026

10.1073/pnas.1217958110

http://click.ndsl.kr/servlet/OpenAPIDetailView?keyValue=05787966&target=NART&cn=NART65711196

lignocellulose; metabolic engineering