Screening Of Cellulose-Degrading Bacteria And Deodorization And Nitrogen In-Situ Preservation In Composting Process

The utilization of straw and livestock manure has always been a hot issue for researchers.As the main component of straw,cellulose is one of the largest renewable resources on the planet.The use of microorganisms for straw cellulose degradation has become a more effective and closer approach to natural ecology.The loss of nitrogen is common in livestock manures used in composting,which reduces the nutrient content of organic fertilizers and causes environmental pollution.The purpose of this study was to screen strains with cellulose degradation ability from compost from pig manure and straw,in order to speed up the compost fermentation process and shorten the fermentation period.At the same time,using the screening of high-efficiency cellulose-degrading bacteria and laboratory-preserved strains(deodorizing desulfurization bacteria)combined with chemical conditioning agents(calcium chloride),three treatment groups were set up,namely:Treatment 1(pig manure + straw),Treatment 2(pig manure + straw + calcium chloride)and treatment 3(pig manure + straw + calcium chloride +mixed bacteria)are used in pig manure and straw compost fermentation to provide a reliable composting plan for controlling nitrogen losses.Provide scientific basis for improving compost quality.This study draws the following conclusions:(1)The Congo red medium and filter paper strip degradation tests were used as primary screens,and enzyme activity was measured in liquid fermentation culture.Two strains of carboxymethyl cellulose(CMC)enzyme activity and high filter paper(FPA)enzyme activity were obtained.Through a series of identifications,it is known that strain 1 is Bacillus subtilis and strain 7 is Cryptococcus flavescens.The results of enzyme production were studied.The results showed that under the condition of pH 6.5 and culture time 48 h,the CMC enzyme activity of No.1 and No.7 strains reached 26.82,31.28 U/mL,and the FPA enzyme activity reached 20.32,30.82.U/mL.(2)During the composting process,the reactor temperature>50℃ days:Treatment 1(22 d)<Treatment 2(27 d)<Treatment 3(30 d)to meet the hygienic and harmless hygiene standards,pH value,moisture content in each treatment group The trend of change is similar.The addition of the bacterial treatment group 3 can accelerate the decomposition of organic carbon(TOC)and increase the content of total nitrogen(TN),total potassium(TK)and total phosphorus(TP).At the end of the test,T<0.6 for each treatment group had reached a complete maturity.(3)The addition of different types of conditioners in the heap can reduce odor generation and reduce N loss.The odors of the treatment groups were:26,16 and 10 days.The release of NH3 and H2S in the experimental group were as follows:treatment group 1>treatment group 2>treatment group 3.Adding CaCl2 and bacterial agents significantly attenuated the odor volatilization in the heap.The effect of adding different types of regulators on the N content in the reactor body was:as the composting progressed,TN increased gradually,NH4+-N increased first and then decreased,and gradually converted to NO3--N.At the end of composting,the experimental group NO3--N content was 1200,1560,and 1580 mg/kg,respectively.(4)During the composting process,the changing characteristics of N-converting key microbial flora was that the number of ammoniated bacteria increased first and then decreased,and the number of nitrifying bacteria,denitrifying bacteria,and azotobacteria increased gradually.The number of 4 N-converting key microorganisms in treatment group 3 was higher than other treatments.There was a significant positive correlation between ammoniated bacteria and NH3 and NH4+-N.There was a negative correlation between nitrifying bacteria and NH3 and NH4+-N and a positive correlation between NO3--N and denitrifying bacteria.Negative correlation was found between NH3 and denitrifying bacteria.N was significantly positively correlated.