Screening And Application Of Deodorizing Microorganism In Pig Excrement Composting And Deodorization Mechanism Study

The annual output of animal manure has been rising year by year in China with the development of animal husbandry and poultry farming.Animal manure can cause resources waste and serious environmental pollution when discharging to the environment without reasonable treatment.Pig manure is the main proportion of animal manure,adding microbial inoculants for composting has been widely used in pig manure compost.However,the releasing of ammonia reduces the nitrogen content in the process of pig manure compost,and influences the industrial production.In this paper,high efficient deodorization microorganism was screened,the fermentation medium and conditions of thermostable deodorization bacteria were optimized.The deodorization microorganism were applied to pig manure compost in this paper,and the mechanism of deodorization and nitrogen keeping of deodorization bacteria were investigated.For the purposes of deodorization in pig manure compost process,the mesothermal deodorization bacteria 1-6 and thermostable deodorization bacteria S4 which have high ability to remove ammonia were screened from soil,pig manure compost and activated sludge.According to morphological physiological and biochemical characteristics and partial sequencing analysis of their 16S rDNA genes,the deodorization strains were identifiedas Bacillus amyloliquefaciens 1-6 and Bacillus lincheniformis S4.The ammonia removal efficiency of 1-6 and S4 were 52.74%and 45.22%,respectively.The fermentation medium and cultivation conditions of S4 were optimized in triangular flasks.The optimum fermentation medium contains(g/L):glucose 15,yeast powder 20,KH2PO4 1.5,MgSO4 1.0,MnSO4 0.005,CaCl2 0.3.The optimum cultivation conditions were temperature 37?,initial pH 8.0,inoculum amount 2%(v/v),loaded liquid 30 mL/250 mL.Under the optimum fermentation medium and conditions,the biomass of S4 was 1.48 ×1010 CFU/mL.The high temperature aerobic composting test has been done,which pig manure and corn straw were taken as the raw material.Deodorization effect of deodorization microorganism was measured in the self-made composting reactor.In the composting experiment of single deodorization bacteria,the inoculantion of thermostable deodorization accelerated rate of temperature increase of compost pile,prolonged the high temperatureperiod by 3 days.In initial stage of high temperature period,NH3 release of compost reached maximum.The Ammonia release quantity of mesothermal deodorization bacteria(T1)and thermostable deodorization bacteria(T2)respectively were 437.67 mg/h and 576.18 mg/h,which far lower than the control group(CK)ammonia release a quantity to 967.53 mg/h,the total ammonia release of T1 and T2 respectively decreased by 38.44%and 38.44%comparing with CK group.The growth rate of total nitrogen content of T1 and T2 were 1.69 times and 1.93 times to CK,deodorization bacteria have the effect of deodorization and nitrogen keeping in pig manure composting.The deodorization effect of recombination deodorization bacteria in the composting was carried on..The Ammonia release quantity of deodorization bacteria(T2)respectively was 543.29 mg/h,which far lower than that of the control group(CK)and maturity inoculant(T1)which respectively were 766.45 mg/h and 1148.64 mg/h,the total ammonia release of T2 respectively decreased by 64.52%comparing with the CK group.The increase rate of of total nitrogen content of T2 was respectively 1.46 times and 2.23 times to CK and T1.The application of two deodorization bacteria has higher effective deodorization than single strain in pig manure compost.In this paper,the mechanism of deodorization and nitrogen keeping of deodorization bacteria was studied.Deodorization bacteria 1-6 and S4 have antagonism in restraining odor production bacteria and putrefying bacteria.Deodorization bacteria had a certain ability to produce organic acid and could lower the pH of compost pile to reduce the release of ammonia in the compost,the acetic acid production of strains 1-6 and S4 were 379.20 mg/L and 318.29 mg/L respectively.The deodorization bacteria could use different organic ammonia,1-6 and S4 had strong ability of ammonia nitrogen utilization to convert ammonia into nitrate.The sequencing result of ammonia monooxygenase gene(amoA)shows that Bacillus amyloliquefaciens 1-6 is heterotrophic nitrosobacteria.The inoculation of deodorization bacteria increased the number of heterotrophic nitrosobacteria of compost pile,and thus reduced the release of ammonia.