Screening and Identification of a Lignocellulose Degrading Strain and the Condition Optimization

Abstract

Lignocellulose, the most abundant renewable resource in the world, is not fully utilized due to degradation difficulty. As a result, microbial biodegradation of lignocellulose has become a research hotspot. In this paper, a strain Q7 that degrades lignocellulose efficiently was screened from soil, and identified as Aspergillus niger by morphology and molecular biology. The enzyme-producing conditions were optimized. SEM, FTIR, XRD and TGA of the degraded lignocellulose were performed. The FPA activity of Q7 reached maximum (23.02 U/mL) with 3% straw powder as the carbon source of medium, 1.5% peptone as the nitrogen source, pH = 5, 30 °C. SEM, FTIR, XRD and TGA of the degraded cellulose residue were carried out, which found that the structure of straw was obviously destroyed, the characteristic peaks of some functional groups disappeared, the crystallinity increased, and the decomposition temperature and maximum degradation temperature (Tmax) of the fermented straw increased.