Improved enzymatic hydrolysis of corn stover by a low-temperature and low-pressure holding post-treatment.

Abstract

Lignocellulose is one of the world's most abundant and underutilized biomass resources, and its proper treatment and utilization are critical to environmental issues and sustainable development. However, lignocellulose's inherently compact and intricate structure reduces enzymatic hydrolysis's efficiency, which is still an obstacle to overcome. A new pretreatment method with relatively low-temperature and low-pressure holding (LTLPH) after the traditional extrusion, pulp refining instrument (PFI), and instant catapult steam explosion (ICSE) was proposed to obtain a better output of corn stover saccharification. The chemical composition, SEM, swelling capacity of corn stover before and after treatment, and types and contents of mixed sugars were examined to explore the mechanism for the diversity of the enzymatic hydrolysis effect. It was found that the highest reducing sugar in the optimized compounding pretreatment method of ICSE-LTLPH (LTLPH: 70 kPa, 115 °C, 30 min) could reach 27.96 g/L, promoting more than 50%. The cultured single-cell protein content was 8.19% and 7.73% higher than those with glucose and simulated mixed sugar medium, respectively, promisingly replacing commercial sugars for Candida utilis (C. utilis) growth. Therefore, the developed pretreatment method of ICSE-LTLPH could exert better effects on the enzymatic hydrolysis of corn stover, providing a potential for cultivating C. utilis without detoxification of enzymatic hydrolysate.