Effect Of Thermophilic Bacteria On Aerobic Composting Of Rice Straw

Aerobic high-temperature composting is one of the best methods for the treatment of crop straw wastes,which can promote the utilization of crop straw resources.In this process,the change of material by adding microorganisms is closely related to the evaluation of maturity and the guiding significance for the production and application of compost.In this study,various thermophilic bacterias from compost sample were screened for different combinations and inoculated into the piles with rice straw as raw material by means of exogenous addition,and its effect on composting process was also evaluated.The main results obtained in this stusy are as follows:(1)65℃ as the standard,seven thermophilic bacteria strains were isolated and identified from compost samples,named F13,F23,F7,F9,F10,F50,F2,respectively,Among which,F13 and F23 belong to G.stearothermophilus,F7,F9,F10 belong to G.thermodenitrificans,F50 belongs to G.thermoglucosidasius,F2 belongs to Gacillus.(2)Biological,physicochemical and material characteristic parameters were used as criteria for tracking the composting process.The results showed that the temperature of all treatments were maintained for 17 days(or more)above 50℃ which met the standards of harmless treatment and mature evaluation.After composting,by comparing with the CK,the other four treatments accelerated the composting processand promoted the decomposition and transformation of organic mater in the early stage and humus synthesis in the later stage of composting,so as to reach the maturity standard and improve the quality of composting.(3)The results of the three-dimensional fluorescence spectra showed that the content of protein substances in the five treatments was low,the change was not obvious during the process of high-temperature composting.However,the content of humic acid and fulvic acid increased gradually,which proved that the compost was becoming more and more mature.In this experiment,the compost processing Y1,Y2,Y3 and Y4 reached maturity at 35th days,while CK reached the maturity at the 63rd days.(4)The results of bacterial biodiversity analysis at the thermophilic stage of composting showed that at the phylum level,the relative abundances of Firmicutes,Proteobacteria,Bacteroides,Chloroflexi,Actinobacteria and Tenericutes were relatively high.At the genus level,the microorganisms were capable of degrading cellulose,such as Flavobacterium,Sporosarcina,Ruminiclostridium,Psychrobacillus,etc.which also have a relatively high abundance and become the most dominant in the thermophilic phase.These microorganisms played a critical role during the composting process,which were the main degraders of organic matter,and were related to the degradation of cellulose and lignin being difficult to decompose.