초록
<P><B>Abstract</B></P> <P>Rice straw (RS) is one of the most abundant lignocellulosic biomasses in China, which contains mainly of cellulose, hemicellulose and lignin. In this study, a novel deep eutectic solvent (DES), foraceline, was prepared with choline chloride and double hydrogen bond donors (formic acid and acetic acid). By combining foraceline and sodium carbonate (1%), a two-stage pretreatment method was developed and applied in RS pretreatment to improve the biodegradability of lignocellulose. The highest glucose and total sugar of 37.3 g·L<SUP>−1</SUP> and 42.8 g·L<SUP>−1</SUP> were obtained after hydrolysis of 24 h using 50 FPU· g total solid - 1 of cellulase. The cellulase attached to RS was reutilized for five continuous cycles in which enzyme loading was reduced from 50 FPU· g total solid - 1 (Cycle I) to 30 FPU· g total solid - 1 (Cycle V), resulting in total sugar of 41.3–42.6 g·L<SUP>−1</SUP> for each cycle. RS hydrolysates (Cycle I and V) was utilized in butanol fermentation by <I>Clostridium saccharobutylicum</I> DSM 13864, achieving butanol titer and yield of 9.5 g·L<SUP>−1</SUP> and 0.25 g· g total sugar - 1 , similar to those of glucose medium. This study demonstrated the feasibility of this newly developed biomass pretreatment by dihydrogen bonding DES featuring cellulase recycling and high butanol yield.</P> <P><B>Highlights</B></P> <P> <UL> <LI> DES was synthesized with choline chloride and double hydrogen bond donors. </LI> <LI> A two-stage pretreatment was developed with total sugar of 42.8 g·L<SUP>−1</SUP>. </LI> <LI> Cellulase dosage was reduced for 40% in 5 continuous enzyme recycle. </LI> <LI> Butanol titer of 9.5 g·L<SUP>−1</SUP> was achieved with rice straw hydrolysates. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>