Inhibition of microbial biofuel production in drought-stressed switchgrass hydrolysate

作者：Rebecca G. Ong, Alan Higbee, Scott Bottoms, Quinn Dickinson, Dan Xie, Scott A. Smith, José Serate, Edward L. Pohlmann, A. Daniel Jones, Joshua J. Coon, Trey K. Sato, Gregg R. Sanford, Dustin Eilert, Lawrence G. Oates, Jeff S. Piotrowski, Donna M. Bates, David Cavalier, Yaoping Zhang · 发表于：Biotechnology for Biofuels · 年份：2016 · DOI：10.1186/s13068-016-0657-0 · 被引用次数：51 · 研究领域：Biofuel production and bioconversion、Bioenergy crop production and management、Anaerobic Digestion and Biogas Production

Interannual variability in precipitation, particularly drought, can affect lignocellulosic crop biomass yields and composition, and is expected to increase biofuel yield variability. However, the effect of precipitation on downstream fermentation processes has never been directly characterized. In order to investigate the impact of interannual climate variability on biofuel production, corn stover and switchgrass were collected during 3 years with significantly different precipitation profiles, representing a major drought year (2012) and 2 years with average precipitation for the entire season (2010 and 2013). All feedstocks were AFEX (ammonia fiber expansion)-pretreated, enzymatically hydrolyzed, and the hydrolysates separately fermented using xylose-utilizing strains of Saccharomyces cerevisiae and Zymomonas mobilis. A chemical genomics approach was also used to evaluate the growth of yeast mutants in the hydrolysates. While most corn stover and switchgrass hydrolysates were readily fermented, growth of S. cerevisiae was completely inhibited in hydrolysate generated from drought-stressed switchgrass. Based on chemical genomics analysis, yeast strains deficient in genes related to protein trafficking within the cell were significantly more resistant to the drought-year switchgrass hydrolysate. Detailed biomass and hydrolysate characterization revealed that switchgrass accumulated greater concentrations of soluble sugars in response to the drought and these sugars were subse...