Isolation And Identification Of The Highly Efficient Strains To Degrade Livestock Slaughter Waste And Assessment Of Its Effect In Compost

China is a large country of animal husbandry in the world.A large amount of livestock manure and slaughter waste were produced every year,which pollute the environment seriously.Composting technology is a harmless and resource utilization method.This project hopes to develop a kind of compound microbial agent which could effectively improve the degradation efficiency and product quality of livestock slaughter waste composting.Firstly,a natural aerobic composting system of cattle slaughter waste was constructed,from which the strains resistant to high temperature and efficient degradation of protein and lipid were isolated and screened.Then the strains without antagonistic effect were selected to prepare compound microbial agent.It was used in the composting experiment of cattle and poultry slaughter waste to explore its effect on composting degradation efficiency and product quality.The main experiment results are as follows:1.A natural aerobic composting system of cattle slaughter waste was established and the physical and chemical indexes of composting samples in different periods,such as temperature,degradation rate,C/N,moisture content,pH value,electrical conductivity,E4/E6 value and germination index were assessed during the preriod.Results showed that the degradation rate of cattle slaughter waste reached 80.68%at the end,indicating that the composting system was rich in protein and lipid degradation bacteria.At the same time,other evaluation indexes also show that the samples of natural aerobic composting are completely mature,and the composting products are safe and effective,which can be used as a source for screening strains for efficient degradation of protein and lipid.2.Three strains?W-01,W-02 and W-03?of high temperature resistance and efficient degradation of protein and lipid were isolated and screened from the natural aerobic composting samples of cattle slaughter wastes,which were identified as Bacillus subtilis,Bacillus pumilus and Bacillus velezensis,respectively.Strain W-01 is a facultative degradation strain of protein and lipid.Its protease activity and lipase activity in vitro were?48.13±2.12 U/mL?and?7.33±0.22 U/mL?,respectively.At the same time,there was no antagonism among the three strains,so the compound microbial agent for composting cattle and poultry slaughter wastes could be prepared.3.In the composting experiment of cattle and poultry slaughter wastes,inoculation with microorganism could effectively increase temperature of the cattle and poultry slaughter wastes composting,prolong the duration of high temperature period,and accelerate the degradation rate of slaughter wastes.The degradation effect of 2%mixed bacteria agent treatment group?TC2 and TP2?was the best,reaching 97.36%and 96.14%at the end of composting.Compared to the control group?CKC and CKP?,it increased by 19.91%and 26.91%,respectively.At the same time,the mixed bacterial agent can accelerate the decomposition of organic carbon in the process of composting,reduce the loss of nitrogen and the moisture of the final composting product,and improve the quality.In addition,the electrical conductivity and E₄/E₆ value of compost samples in the treatment group were lower than those in the control group,and the germination index in the treatment group was higher,indicating that the inoculation of compound microbial agent could make the composting products more stable and more mature.Based on the above experimental results,it indicated that the three strains have good protein and lipid degradation effect.The prepared compound microbial agent can effectively improve the composting degradation efficiency and composting product quality of cattle and poultry slaughter wastes,and has a certain application potential in harmless and resource utilization of livestock and poultry slaughter wastes.