Abstract：The northern region is one of the main crop growing areas in China. However, due to the cold and dry climate and the sandy soil, the agricultural residues are decomposed slowly or even cannot be completely degraded, not only making it unable to be used as a fertilizer source in the current season, but also causing the phenomenon that straw and subsequent crops compete for nitrogen and eventually affect the growth of crops. Stacked straws are burned in large quantities, which cause waste of resources and serious air pollution. In order to solve the problem of straw degradation in cold regions, a strain that could efficiently degrade cellulose at low temperature was isolated through the method of Congo red staining and low-temperature screening. The molecular biological identification of the isolation was carried out based on the 18S rDNA sequence analysis. The fermentation conditions of the strain and the characteristics of the cellulase produced were optimized through single factor experiments and response surface method (RSM). Besides, the straw degradation ratio and the dynamic enzyme activity in the low-temperature fermentation progress were determined to investigate the biodegradability of the target strain on rice straw at 10 ℃. The results showed that the isolated strain was identified as Penicillium (Penicillium sp. JiTF01, GenBank No. MZ285877), which could degrade cellulose at 10 ℃ . The optimal fermentation conditions for JiTF01 to produce cellulase at low temperature were pH of 6.67, inoculation amount of 2.89% and incubation time of 12.13 days, and the maximum cellulase activity obtained under the optimized conditions was 31.05 U/mL. Also, strain JiTF01 had been proved that it could exhibit high cellulase activity under acidic conditions, and the enzymatic activity and stability of the cellulase produced by JiTF01 could retain 41.93% and 94.35% at pH 2, respectively. In addition, it was found that the degradation ratio of rice straw could reach 45.24% after 21 days of fermentation by strain JiTF01 at 10 ℃ . The conclusions found in this study are significance to the production and application of cellulase in the future and have important implications for the disposal of straw resources in cold regions.
董雪丽, 季静, 张松皓, 王罡, 王昱蓉. 一株耐低温纤维素降解菌的发酵条件优化和秸秆降解研究[J]. 农业生物技术学报, 2022, 30(5): 978-989.
DONG Xue-Li, JI Jing, ZHANG Song-Hao, WANG Gang, WANG Yu-Rong. Study on Optimization of Fermentation Conditions and Straw Degradation of A Low Temperature Resistant Cellulose Degrading Strain. 农业生物技术学报, 2022, 30(5): 978-989.
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