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

The transcriptome data of Thermoanaerobacterium aotearoense SCUT27 (SCUT27) and Thermoanaerobacterium aotearoense SCUT27/Delta argR(1864) (SCUT27/Delta argR(1864)) under xylose showed that ArgR(1864) was the negative regulator for chaperonin synthesis. With argR(1864) knockout, the mutant showed upregulated 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/Delta argR(1864) 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%. (C) 2021 Elsevier Ltd. All rights reserved.