Promoting microbial fermentation in lignocellulosic hydrolysates by removal of inhibitors using MTES and PEI-modified chitosan-chitin nanofiber hybrid aerogel

Abstract

To further enhance the removal efficiency for furanic and phenolic compounds in lignocellulosic hydrolysates, a new detoxification strategy was proposed, which retained fermentable sugars and promoted the growth and metabolism of subsequent bacteria. The best adsorbent (P/M-CCA) was prepared by hybrid chitosan-chitin nanofiber, graft modification with polyethylenimine, and silanization with methyl triethoxylsilane in order. Taken corn cob hydrolysate as object, the removal rates of HMF and furfural were 85.1 % and 99.0 %, respectively. The removal rates of six out of nine phenolic inhibitors were 100 %, and the other three were more than 65 %. Even better, the retention rates of glucose and xylose were both 100 %. In contrast to no growth in undetoxified hydrolysates, Bacillus coagulans grew normally in detoxified hydrolysates, and lactic acid reached 19.1 g/L after 12 h fermentation. P/M-CCA achieves both removal of multiple inhibitors and retain sugars, which would promote the valorization of highly toxic lignocellulosic hydrolysates.

Keywords: Chitosan-chitin nanofiber hybrid aerogel; Detoxification; Inhibitors; Lignocellulosic hydrolysates; Phenols.