Inhibitions of microbial fermentation by residual reductive lignin oil: Concerns on the bioconversion of reductive catalytic fractionated carbohydrate pulp

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-01, Vol.452, p.139267, Article 139267
• Main Authors: Wu, Yilu, Wen, Jieyi, Su, Changsheng, Jiang, Chenhang, Zhang, Changwei, Wang, Yankun, Jiang, Yongjie, Ren, Wenqiang, Qin, Peiyong, Cai, Di
• Format: Article
• Language: English
• Subjects: Bio-alcohols fermentation; Biorefinery; Lignin oil; Microbial inhibition; Reductive catalytic fractionation
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2022.139267

[Display omitted] •Reductive catalytic fractionated lignin oil possessed inhibition effect to microbes.•The alkyl substitute phenols exhibited higher inhibition than other monolignols.•Eukaryotes have higher tolerance to reductive catalytic fractionated lignin oil.•Bio-alcohols can be produced from the lignin oil contaminated pulps. Reductive catalytic fractionation (RCF) is an emerging biomass valorization strategy with high atom economy, which primarily outputting extensively depolymerized reductive lignin oil and highly delignified pulp. In downstream processes, the polysaccharide rich pulp can be potentially transferred into various value-added biochemicals through fermentation. In this study, the negative influences of the residual lignin oil that remaining on the surface of the RCF pulp towards different industrial microbes (total 9 species, categorized into eukaryotes, Gram-negative, and Gram-positive strains) was investigated. Results indicated the reduced lignin fractions were the key inhibitors in the RCF lignin oil, whilst the polarities, molecular weight, and the substitution groups of lignin possessed significant impacts on the growth of strains. Meanwhile, the resistance to RCF lignin oil by different category of industrial strains was analyzed. Generally, eukaryotes exhibited better resistance than the Gram-negative and Gram-positive strains. Took bioethanol and acetone-butanol-ethanol fermentation as examples, the negative influence of the lignin oil on biochemicals production using the RCF pulp as substrate was explored. Batch fermentation results revealed that the RCF lignin oil limited both the sugars (glucose and xylose) metabolism and the pathways toward bio-alcohols production of the microorganism. Therefore, it is vital to take continuous technical improvement in order to minimize the negative influences of the residual lignin oil on downstream biotransformation of the RCF pulps.