Establishment of a Highly Efficient Corn Stock-Degrading Microbial Consortium and Its Degradation Effect

Abstract

Corn stalks are not easily degradable and thus have a low utilization rate. In this paper, a highly efficient corn stalk-degrading microbial consortium, designated as SDP, was established using the strains Z22 (Bacillus subtilis), Z15 (Bacillus megaterium), and Z08 (Aspergillus tubingensis). Moreover, the fermentation conditions for enzyme production by SDP were optimized through orthogonal experiments. The Van Soest method was used to determine the cellulose, hemicellulose, and lignin contents in the degraded corn stalks using the SDP consortium to evaluate its degrading effect. Scanning electron microscopy was used to analyze the micromorphological structure changes of the stalks to evaluate the degradation effects of SDP on corn stalks. The carboxymethyl cellulase activity of SDP reached 6.37 U/mL. Moreover, the enzyme production effect was optimal when the culture conditions were as follows: temperature, 30°C; time, 5 d; nitrogen source, NH4NO3; and initial pH, 7.0. The SDP consortium showed an improved ability to degrade corn stalks. The cellulose, hemicellulose, and lignin contents were reduced by 32.15%, 23.87%, and 7.98%, respectively, after culturing for 20 d. This study provides insights to guide further research and development of consortia for efficient corn stalk degradation.