Screening of a lignin decomposing bacterium and its application in bamboo biomechanical pulping

Bamboo is an excellent raw material for papermaking, offering advantages such as a simple papermaking process, abundant availability, short growth cycle, and significant ecological effect. However, the lignin content in bamboo greatly restricts its effective utilization of bamboo pulp. In this study, a strain of SF-6, an efficient ligninolytic bacterium, was screened from bamboo rat feces under restrictive culture conditions and identified as Enterobacter sichuanensis by 16S rDNA. The main factors affecting the fermentation of SF-6 was determined by a one-way test, and the optimal culture temperature of the strain was 36.8 °C. The inoculum amount and pH value were determined by response surface analysis. The optimum culture temperature was 36.8 °C, the inoculum amount was 7.5%, and the initial pH was 5.2. Under these conditions, the decomposition rate of lignin was 38.59%, which was 55.42% higher than that before optimization, the paper tear resistance was improved by 73.2%, the breakage strength was improved by 62.41%, and the amount of alkali used was only 1.5 times that of the traditional chemical method. In conclusion, bamboo pulping with SF-6 resulted in a good pulping performance, less energy consumption, and no harm to the environment. Therefore, this is a feasible preparation method. This study provides a new microbial source for lignin degradation.