关键词: 低温, 纤维素降解菌, 纤维素酶, 优化, 纤维素降解率

Abstract: An effective solution to resolve the problems of slow start of cow manure composting and long fermentation cycle in winter is the addition of lowtemperature cellulose-degrading microbe to the pile. However, few types of low-temperature cellulose-degrading microbe are available. In this study, one low-temperature and high-efficiency cellulose-degrading strain was isolated from frozen cow dung under low temperature conditions, which was named YSX-3. It was identified as Pseudomonas. In order to obtain its optimal enzyme production condition, on the basis of single factor optimization, incubation time, incubation temperature, initial pH value and inoculum amount are considered as independent variables, and cellulase activity as the response variable. Response surface analysis (RSM) was used to analyze the relationship between response variable and the independent variables. The results showed that the optimal enzyme production condition of YSX-3 strain was as follows: inoculating amount 4%, culture temperature 9 ℃, culture time 71 h and initial pH 6.5. Under this condition, the cellulase activity was 130.21 U·mL^-1, which was 1.3 times higher than that before optimization. The optimized YSX-3 strain was inoculated into the manure pile. On the fifth day, the high-temperature period came (>50 ℃), the temperature reached up to 62.5 ℃, and the high temperature period lasted for nine days. At the end of composting, the degradation rate of cellulose reached 45.2%, while that in the control group was only 15.4%.

Key words: low temperature, cellulose-degrading bacterium, cellulase, optimization, cellulose degradation rate.