1株木质素降解菌的筛选、鉴定及液态发酵条件优化

  目的  制作应用于园林绿化废弃物的以木质素降解菌为原材料的高效液体菌剂。  方法  通过苯胺蓝平板褪色圈法和愈创木酚平板变色圈法从分离纯化得到的22株菌中筛选目标菌株，并用内转录间隔区(ITS)测序法对目标菌株进行鉴定，然后通过单因素试验对目标菌株的培养时间、接种量和培养基配方(碳源和氮源)进行优化，最后根据单因素试验结果，采用均匀实验结合人工神经网络算法寻找目标菌株的最佳发酵条件。  结果  根据平板褪色和显色结果，选定菌株Q01为目标菌株。经鉴定，菌株Q01为栓菌属Trametes真菌。根据单因素试验和均匀试验结果，确定菌株Q01的最优发酵条件为培养时间5 d，接种菌液体积分数为12.5%；培养基配方为木质素磺酸钠14.00 g·L?1、蛋白胨12.30 g·L?1、酵母粉5.00 g·L?1、豆饼粉3.00 g·L?1、五水合硫酸铜0.12 g·L?1、氯化钠0.53 g·L?1、pH自然。优化条件后菌株Q01的生物量提高1.27倍，锰过氧化物酶活性提高31.71倍，木质素过氧化物酶活性提高19.12倍，漆酶活性略有降低，但3种木质素酶的总酶活性提高了4.38倍。  结论  菌株Q01在优化后的发酵条件下制得的液体菌剂具有高酶活性和高生物量的特点，在降解园林绿化废弃物木质素方面具有一定应用潜力。图6表3参29

Screening and identification of a lignin degrading strain and its optimized liquid fermentation conditions

  Objective  The purpose is to produce a high efficient liquid inoculum with lignin-degrading bacteria as raw materials for garden waste.  Method  The target strains were screened from 22 isolated and purified strains by the aniline blue plate fading circle method and the guaiacol plate fading circle method, and were identified by Internal Transcribed Spacer (ITS) sequencing, and then the single factor test was used to optimize the culture time, inoculum amount and medium formula (carbon and nitrogen source) of the target strains. Finally, according to the results of single factor test, the optimal fermentation conditions of the target strains were found by uniform experiment combined with artificial neural network algorithm.   Result  According to the results of plate fading and color development, strain Q01 was selected as the target strain and was identified as Trametes. According to the results of single factor test and uniform test, the optimal fermentation conditions for strain Q01 were determined as the culture time of 5 days, inoculation amount 12.5%. The medium formula was composed of sodium lignosulfonate 14.00 g·L?1, peptone 12.30 g·L?1, yeast powder 5.00 g·L?1, soybean cake powder 3.00 g·L?1, copper sulfate pentahydrate 0.12 g·L?1, sodium chloride 0.53 g·L?1, and natural pH. Under the optimized conditions, the biomass, manganese peroxidase activity and lignin peroxidase activity of strain Q01 increased by 1.27 times, 31.71 times and 19.12 times respectively. Laccase activity decreased slightly, but the total enzyme activities of three kinds of lignin enzymes increased by 4.38 times.   Conclusion  The liquid inoculum prepared by strain Q01 under optimized fermentation conditions has the characteristics of high enzyme activity and high biomass, which has certain application potential in degrading lignin in garden waste. [Ch, 6 fig. 3 tab. 29 ref.]