Exploring The Succession Mechanism Of Microbial Community During Chinese Medicinal Herbal Residue Composting

Tens of millions of tons of Chinese medicinal herbal residue were produced each year from China with the development and utilization of Chinese herbal resources in recent year.If improperly disposed,it will cause serious environmental pollution.The traditional treatment methods(such as incineration or landfill)were costly and had the risk of secondary pollution.Recycling such waste was an urgent problem to be solved.At present,biological treatment was the most promising technology.The composting process can realize the harmlessness,reduction and resource utilization of waste.Chinese medicinal herbal residue can be treated by composting,because it contained a large amount of organic matter and nutrient elements.Its lignocellulose content was high,and it was difficult to degrade and the composting period was long.Microorganisms played a vital role in degradation during composting.The microbial inoculant composition and composting process were further optimized by studying the microbial community succession mechanism during composting.Therefore,it was of great significance to explore the microbial community succession mechanism in the composting process of Chinese medicinal herbal residue.In the study,Chinese medicinal herbal residue were used to compost.Miseq highthroughput sequencing technology was used to compare and analyze the changes of microbial community structure during natural composting and EM microbial composting.The main results were as follows:1.A total of 449260 effective sequences were obtained from 12 samples of bacteria,which were classified into 16 phylum,34 classes,76 orders,172 families and 382 genus.A total of 442339 effective sequences were obtained from 12 samples of fungal,which were classified into 3 phylum,9 classes,10 orders,16 families and 24 genus.2.In the process of composting of Chinese medicinal herbal residue,the dominant microorganisms in bacterial community at the phylum levels were Proteobacteria,Actinobacteria and Firmicutes.At the genus levels were Streptomyces,Bacillus and Lactobacillus.3.In the process of composting of Chinese medicinal herbal residue,the dominant microorganisms in fungal community at the phylum levels were Ascomycota.At the genus levels were Aspergillus,Thermomyces,Monascus and Malbranchea.4.The variation of bacterial microbial community structure succession during different composting processes was as follows:(1)In the process of natural composting,the dominant group of bacterial community at the phylum levels were transformed from Proteobacteria and Firmicutes in the early stage of composting to Proteobacteria,Firmicutes and Actinobacteria in the middle of composting,and then transformed into Proteobacteria and Actinobacteria in the late stage of composting.The dominant group of bacterial community at the genus levels were transformed from Bacillus,EscherichiaShigella and Klebsiella in the early stage of composting to Streptomyces and Bacillus in the middle of composting,and then transformed into Streptomyces,Saccharopolyspora and Actinomadura in the late stage of composting.(2)In the process of adding EM microbial compost,the changes in the dominant group of bacterial community levels were similar to those of natural composting.The dominant group of bacterial community at the genus levels were transformed from Lactobacillus and Weissella in the early stage of composting to Streptomyces and Lactobacillus in the middle stage of composting,and then transformed into Streptomyces in the late stage of composting.5.The variation of fungal microbial community structure succession during different composting processes was as follows:(1)In the process of natural composting,the dominant group of fungal community at the phylum levels were Ascomycota.The dominant group of fungal community at the genus levels were transformed from Aspergillus in the early stage of composting to Aspergillus and Thermomyces in the middle of composting,and then transformed into Aspergillus,Thermomyces and Malbranchea in the late stage of composting.(2)During the composting process of adding EM bacteria,the dominant group of fungal community at the phylum levels were Ascomycota.The dominant group of fungal community at the genus levels were transformed fromAspergillus and Monascus in the early stage of composting to Aspergillus in the middle and late stage.6.The variation of microbial community diversity index with time was different in different composting methods and different types.Among them,the Alpha diversity index and richness index of bacterial community showed a gradual increase trend with the composting time in both composting methods.The Alpha diversity index of fungal community gradually showed a gradual increase trend with the composting time in natural composting.However,there was no significant change in the addition of EM microbial composting.7.Among the changes of physical and chemical indexes in the process of Chinese medicinal herbal residue composting,the results of temperature and humic acid showed that the effect of natural composting was better than that of EM composting.