Enhanced ethanol production from lignocellulosic hydrolysates by Thermoanaerobacterium aotearoense SCUT27/ΔargR1864 with improved lignocellulose-derived inhibitors tolerance

Abstract The transcriptome data of Thermoanaerobacterium aotearoense SCUT27 (SCUT27) and Thermoanaerobacterium aotearoense SCUT27/ΔargR1864 (SCUT27/ΔargR1864) under xylose showed that ArgR1864 was the negative regulator for chaperonin synthesis. With argR1864 knockout, the mutant showed up-regulated expression of DnaK-DnaJ-GrpE system and GroEL-GroES chaperonin, which not only endowed the strain with the ability to scavenge the reactive oxygen species (ROS), but also gave the mutant the capability to maintain better cell growth, xylose consumption, acetic acid and ethanol production under the stress of various lignocellulose-derived inhibitors. Diluted acid pretreated soybean straw, sorghum stalk and wheat straw hydrolysates were used to evaluate the ethanol production of SCUT27/ΔargR1864 and results showed that the mutant definitely had advantages over SCUT27 for ethanol production under lignocellulosic hydrolysates, with the xylose consumption rate increased by 25.00%–44.83%, the ethanol production improved by 113.86%–366.36% and ethanol yield enhanced by 88.89%–208.33%.