一株木质素降解菌的筛选、鉴定及降解条件优化

Screening and Identification of a Lignin-Degrading Strain and Optimization of Its Degradation Conditions

研究旨在筛选高效木质素降解细菌并优化其降解条件,以提高木质素降解率。以木质素为唯一碳源初筛,通过苯胺蓝脱色圈,木质素过氧化物酶(Lip)、锰过氧化物酶(Mnp)和漆酶(Lac)酶活,以及木质素降解率比较逐步复筛,最终以木质素降解率为指标,通过单因素和响应面法进行发酵降解条件优化。结果显示:试验筛选获得一株木质素高降解菌JG-5-2,可以产生Lip、Mnp和Lac等木质素降解酶,经16S rDNA测序鉴定为Pseudomonas guguanensis。最佳发酵降解条件为温度37℃、培养基初始pH 7.0、接种量2.1%,在此条件下,发酵72 h时木质素降解率达到38%左右。表明菌株JG-5-2在降解木质素方面是优良的备选菌株。

The study aims to screen efficient lignin-degrading bacteria and optimize their degradation conditions to enhance the degradation rate of lignin.Lignin was used as the sole carbon source for initial screening,followed by subsequent screenings based on aniline blue decolorization cycle,lignin peroxidase(Lip),manganese peroxidase(Mnp),laccase(Lac)enzyme activities,and comparison of lignin degradation rate.Finally,based on the lignin degradation rate,the fermentation and degradation conditions were optimized using both single factor and response surface methods.The results showed that a strain JG-5-2 with high lignin degradation rate was screened,which could produce lignin degrading enzymes such as Lip,Mnp,and Lac.It was identified as Pseudomonas guguanensis through 16S rDNA sequence analysis.The optimal degradation conditions were determined to be 37℃ with an initial pH of 7.0 and an inoculum volume of 2.1%.Under these conditions,the degradation rate of lignin reach about 38% after 72 hours of fermentation.These results suggest that strain JG-5-2 is an excellent candidate strain for lignin degradation.