Coproduction of Ethanol and Lignosulfonate From Moso Bamboo Residues by Fermentation and Sulfomethylation

Abstract

A novel integrated process to coproduce bioethanol and lignosulfonate from bamboo residues was investigated. Explicitly, the fermentable sugars (glucose and xylose) were saccharified from the kraft pulped bamboo residues with 12 % effective alkaline charge, followed by a sequential fermentation strategy was applied to produce bio-ethanol from these fermentable sugars. The kraft lignin (KL) generated in pulping process and the enzymatic hydrolysis residues (EHR) were sulfomethylated to produce lignosulfonate. Results showed that 229.8 g of KL, 495.6 g of fermentable sugars (368.7 g glucose and 126.9 g xylose) and 103.6 g of EHR were generated from 1000 g bamboo residues after consequent processes of kraft pulping and enzymatic hydrolysis, respectively. Under optimal conditions of fermentation and sulfomethylation, 1000 g bamboo residues could produce 201.4 g of ethanol (158.7 g from glucose and 42.7 g from xylose) and 234.9 g of pure lignosulfonate (197.6 g from KL and 37.3 g from EHR) from 1000 g bamboo residues. This integrated process may potential be an economically profitable for the biorefinery of bamboo residues.