高温纤维素分解菌Streptomyces thermocarboxydus的分离鉴定及其对毛竹废弃物的降解效果

Isolation and identification of thermophilic cellulolytic bacterium Streptomyces Thermocarboxydus and its degradation effect on moso bamboo waste

  • 摘要: 毛竹加工过程中会产生大量废弃物, 高温好氧堆肥是一种重要的毛竹废弃物利用方式, 其中纤维素的高效降解是堆肥过程提质增效的关键, 分离筛选高温纤维素分解菌对毛竹废弃物的高温堆肥降解具有重要意义。本研究在湖南地区的稻田、草地、竹林和森林土壤, 以及秸秆高温堆肥等存在木质纤维素的环境中采集样品, 以毛竹加工剩余细屑纤维素为唯一碳源在50 ℃条件下富集培养高温纤维素分解菌。通过水解圈法分离筛选高温纤维素分解菌, 比较不同高温纤维素分解菌液体摇瓶发酵条件下的毛竹失重率、纤维素酶(CMCase)活力和滤纸酶(FPase)活力大小, 筛选毛竹细屑降解效果优异的菌株, 并对其进行菌种鉴定、不同温度下的毛竹降解能力以及木质纤维素组分的降解率测定。结果表明水解圈法获得的纤维素分解菌主要为真菌和放线菌, 其中菌株JFDF-S1在50 ℃条件下液体发酵培养5 d时毛竹加工剩余细屑的失重率最高(20.35%), 并且显著高于其他菌株; 同时, 该菌株产生的CMCase和FPase也显著高于其他菌株。经菌落菌体形态学和分子生物学鉴定为Streptomyces thermocarboxydus。菌株JFDF-S1在30~55 ℃条件下的菌落生长和纤维素降解能力较好, 与堆肥过程的中高温条件相吻合, 可通过高效降解毛竹废弃物中的半纤维素和纤维素组分对其进行有效降解。本研究为利用高温纤维素分解菌株JFDF-S1开发毛竹废弃物高效降解的微生物菌剂提供了理论基础, 有利于提高毛竹废弃物的堆肥效率和质量, 促进毛竹废弃物的循环利用和毛竹产业的健康可持续发展。

     

    Abstract: A large amount of waste materials is produced during the processing of moso bamboo (Phyllostachys edulis) . High-temperature aerobic composting is an important way to utilize moso bamboo waste, among which the efficient degradation of cellulose is the key to improving the quality and efficiency of the composting process, the isolation and screening of high-temperature cellulose-decomposing bacteria is of great significance for the high-temperature composting degradation of bamboo waste. In this study, many samples were collected in the environments where lignocellulose exists, such as rice fields, grasslands, bamboo forests, forest soils, and high-temperature composting of straw in Hunan region. High-temperature cellulose-decomposing bacteria were enriched and cultivated at 50 ℃ using the cellulose from the remaining fine chips of bamboo processing as the sole carbon source. High-temperature cellulose-decomposing bacteria were isolated and screened by the hydrolysis ring method. The weight loss rate of moso bamboo, the activity of carboxymethyl cellulase (CMCase), and the activity of filter paper cellulase (FPase) under the liquid shaking flask fermentation conditions of different high-temperature cellulose-decomposing bacteria were compared to screen the strains with excellent degradation effect of moso bamboo fine debris. And the strains were identified, the degradation ability of moso bamboo at different temperatures, and the degradation rate of lignocellulose components were determined. The results showed that the cellulose-decomposing bacteria obtained by the hydrolysis ring method were mainly fungi and actinomycetes. Among them, the strain JFDF-S1 had the highest weight loss rate (20.35%) of the remaining fine chips from bamboo processing when it was cultured in liquid fermentation at 50 ℃ for 5 days, and was significantly higher than that of other strains. Meanwhile, the activity of CMCase and FPase produced by this strain were also significantly higher than those of other strains. It was identified as Streptomyces thermocarboxydus by colony morphology and molecular biology. The colony growth and cellulose degradation ability of the strain JFDF-S1 under the conditions of 30-55 ℃ were relatively good, which is consistent with the medium and high temperature conditions in the composting process. It can effectively degrade bamboo waste by efficiently degrading the hemicellulose and cellulose components in it. This study provides a theoretical basis for the development of microbial agents for the efficient degradation of bamboo waste using the high-temperature cellulose-decomposing strain JFDF-S1. It is conducive to improving the composting efficiency and quality of bamboo waste, promoting the recycling of bamboo waste and the healthy and sustainable development of the bamboo industry.

     

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