Bio-refining corn stover into microbial lipid and advanced energy material using ionic liquid-based organic electrolyte

Abstract

Full utilization of the entire components of lignocellulosic biomass is one of the challenges in modern biorefinery via integrated approaches. This study pioneers an integrated approach to convert carbohydrates and lignin from corn stover into microbial lipids and advanced energy carbon nanofibers for supercapacitors using ionic liquid-based organic electrolyte ([Emim][OAc]/DMSO (XILs = 0.2, XILs is the molar fraction of ILs in the electrolyte). The pretreated corn stover was delignified by 60 wt%, and its saccharification was enhanced from 0.11 g.g−1 total reducing sugar (TRS) and 0.08 g.g−1 glucose to 0.68 g.g−1 TRS and 0.43 g.g−1 glucose yields within 12 h by enzymatic hydrolysis. The hydrolysates were used as carbon sources for cultivating R. toruloides Y4 for lipid production, yielding 13.8 g/L biomass and 51.0 % lipid. The lignin after enzymatic saccharification was integrated with extracted lignin to form a lignin organic electrolyte solution, which was directly prepared into electrospun nanofibers combined with polyacrylonitrile that served as electrode materials for supercapacitors with good performance.