Screening And Application Of Cellulose Degradation Bacteria In Sheep Manure Compost Fermentation

With the development of large-scale livestock and poultry breeding in China,the unreasonable utilization of large amount of livestock and poultry manure has brought great pressure to the environment.The conversion of manure compost into organic manure is one of the effective ways for its resource utilization,and it is also the best way to meet the situation of China.At present,there are many problems in composting treatment,such as slow fermentation,long maturity and low quality of compost.Composting with high-efficiency cellulose-degrading bacteria can promote the degradation of lignocellulose,shorten the compost cycle,and increase the utilization rate of livestock and poultry manure.In this paper,cellulose-degrading strains were isolated from different habitats and commercially available microbial inoculum samples.Through the screening of high-efficiency cellulose-degrading bacteria,the construction of compound microbial inoculum and their application in sheep manure compost fermentation,the main research results are as follows:1.156 strains of bacteria,68 strains of fungi and 43 strains of actinomycetes were obtained through isolation,which with the function of cellulose degrading.7strains with strong cellulose degradability were obtained by further screening,rescreening and identification of 16S rDNA and ITS rDNA sequences.Including bacterias XJB4 and XC4 which belong to Bacillus,bacteria X1 which belong to Paenibacillus,fungus ZN50 and ZP27 which belong to Penicillium,and actinomycetes FJB2 and FJB4 which belong to Streptomyces.2.Antagonistic test showed that there was no antagonism among the above 7strains.After the construction of the compound inoculum,compound microbial inoculum M which contained 7 strains of cellulose degradation could degrade the filter paper into a paste after fermentation for 2 days.The enzyme activities of total enzyme(FPA),exo-enzyme(CX),carboxymethyl cellulase(CMCase)and?-glucosidase(?-Gase)were higher,reaching 146.97 U/mL,85.14 U/mL,7.29 U/mL and 232.81 U/mL,respectively.After 10 days of liquid fermentation,the degradation rate of straw reached 42.15%.3.Inoculated with cellulose degradation compound microbial inoculum M and used for sheep manure straw compost fermentation.Compared to non-inoculated microorganisms(CK),after inoculation of compound microbial inoculum M:(1)The time for the body to warm up to the high temperature period(50~oC)is shortened by 1day and the high temperature stage is extended by 2 days.(2)After 21 days of composting,the seed germination index of the composting was 100.86%,and the maturity cycle was shortened by 4 days compared with the control group.(3)At the end of composting(25 d),the degradation rates of cellulose and hemicellulose were significantly higher than those of the control group(p<0.05),which increased by12.50%and 11.38%.Organic matter increased by 2.00%compared with the control group;the carbon-nitrogen ratio decreased by 3.67;total nitrogen,available phosphorus,and available potassium increased by 11.85%,31.23%,and 34.12%,respectively.There were no significant differences in the physical and chemical properties and nutritional indicators between the commercially available microbial inoculum R and the inoculated with cellulose degradation compound microbial inoculum M(p>0.05)except that the maximum body temperature and cellulose degradation rate of the inoculated with cellulose degradation compound microbial inoculum M were higher than that of commercially available microbial inoculum R(p<0.05).It shows that the cellulose degradation compound microbial inoculum M was used in sheep manure composting,which helps to promote the degradation of cellulose and hemicellulose in the compost,improves and maintains the high-temperature fermentation of the compost body,shortens the composting and maturity cycle,and retains nutrition just like N,P,K,etc.4.By using the second-generation sequencing technology to analyze the composition of microbial communities in different stages of the composting process,the results show that microbiological structure composition does not change much at the phylum level.Proteobacteria(34.49%~64.91%),Firmicutes(14.04%~34.92%)and Actinobacteria(7.51%~32.07%)were dominant bacteria groups at the phylum level.Ascomycota(22.32%~92.63%)and Basidiomycota(0.49%~21.18%)were two dominant fungal groups at the phylum level.At the genus classification level,there were obvious community successions in the microorganisms of different composting stages.At the early stage of composting(0 d),the dominant genera of bacteria included Halomonas and Paracoccus,and the fungi were Acremonium and Sarocladium.At the end of the high temperature period(8 d),the dominant genus of bacteria mainly includes Actinotalea and Paracoccus,and the fungus were Gibellulopsis and Wallemia.At the end of the high temperature period(15 days),the dominant genus of bacteria mainly includes Vibrio and Bacillus,while dominant genus of fungus were Arthrobacter and Aspergillus.At the stage of maturity(25 d),the dominant bacterial groups were Actinotalea and Bacillus and the dominant fungus were Arthrobacter and Gibellulopsis.Inoculation with the compound microbial inoculumM increases the species abundance and diversity of bacteria and fungi in the fermenter body.At the end of the fermentation(25 d),the Chao1 index(806.33,371.08)and the Shannon index(4.84,3.46)of the bacteria and fungi were higher than the control group(761.33,4.48),and the Simpson diversity index(0.02,0.07)was lower control group(0.04,0.07).The correlation analysis between the nutrient components and the bacterial composition in the compost was performed using the redundancy correlation analysis.The results showed that total phosphorus,total nitrogen,and total potassium were positively correlated with fungi such as Halomonas,Acremonium,Archaeorhizomyces,and Cladosporium,and they were highly related.Cellulase-related enzyme activities such as FPA,CMCase,and?-Gase were positively correlated with bacteria such as Bacillus and Vibrio,as well as fungi of the Arthrobacter and Pyrenochaetopsis,and they were highly correlated.