Analysis Of Microbial Community Succession During Swine Manure Composting By PCR-Single-Strand-Conformation Polymorphism

In this study, swine manure and rice straw were used to be compostingmaterials indoor. Two trial groups were set up, which were called staticwindrow of passive aeration (Pile One) and static windrow of forced aeration(Pile Two), respectively. Physical and Chemical parameters, such astemperature, carbon dioxide, pH, moisture content, total organic carbon,total kjeldahl nitrogen, the ratio of carbon to nitrogen, were determined inthirty days. The test samples were taken from both piles at three points ofdifferent depth every 3d, In addition, bacteria and fungi populations weredetected with the biological technique of Single Strand ConformationPolymorphism. The procedures of t-test and correlation analysis in thesoftware of SAS 6.12 were applied to analyze statistically the data obtainedin the experiment in order to understand the development of the microbialstructures within and between piles in different composting phases, therelationship between macroscopic parameters and the succession Of microbialcommunities, and comparing the community of fungi with that of bacterial.The variance curve of physical and chemical parameters indicated that thetwo piles hadexperienced an integrity course of fermentation in compostingprophase, while the results of PCR-SSCP detection manifested that themicrobial populations, composed of bacteria and fungi, changed greatly.The number of bacterial groups descended vibrationally in the 0～100dcomposting process. Community dynamics of fungi in two piles proved that fungipopulation had already flourished in the 9d, whose prosperous stage was the15～24d.Comparing the community of bacterial and fungi, it can be realized that,the correlation analysis of community succession between bacterial and fungimainly reflected weakly negative correlation (r＜0,p＞0.05),that more fungispecies OTUs were amplified by PCR-SSCP than bacteria species in this researchdue to the length of fungi primer being shorter than bacteria primer, that the variance of fungi species was significantly greater than that of bacteriaspecies, that the average numbers of bacteria and fungi in the pile of forcedaeration were higher than those in passive aeration pile (2.436 versus 1.54to bacteria species and 3.128 versus 2.641 to fungi species).Integrating community variation of bacterial and fungi, the results weregained that, the bacterial community predominated obviously before the 15thday. However, the number of fungi groups surpassed that of bacterial groupsand had the advantage all the time, especially in the period of 15～24d, whichkept far away from that of bacterial groups.The number of bacterial groups was significantly positive correlativewith the change of the temperature and carbon dioxide (r＞0,p＜0. 05), and hadextremely significantly positive correlation with the change of total organiccarbon and the ratio of carbon to nitrogen(r＞0,p＜0.01),but had significantlynegative correlation with the change of total kjeldahl nitrogen. While thenumber of fungi groups was significant positive correlative with the changeof pH and moisture content.The bacterial number change tendency was similar to the trend oftemperature and the ratio of carbon to nitrogen changing. In 0～30d, the activestage of bacteria was before the eighteenth day, however, bacterial communitybecame inferior microbial species after that phase. Because the piletemperature was mainly in the scope of forty-four celsius degree toseventy-one celsius degree during thirty composting days, aerobic andthermophilic bacteria amplified by PCR-Single Strand ConformationPolymorphism may be the prevailing microbial population.Through the curve of the standard data derived from the fungi communitynumber and the macroscopic parameters such as temperature, the ratio of carbonto nitrogen and total kjeldahl nitrogen, it was observed that, the optimaltemperature for fungi may be 42.5～50 celsius degree. And the ratio of carbonbecame unsuitable for bacteria to grow, which may benefit the growth of fungi.The relative amount of total kjeldahl nitrogen became more and more high, which may inhibit the propagating of fungi in coordination with temperature.Standard data transformed from the ratio of the number of bacterial andfungi groups to their corresponding average number, indicated that, thebacterial community was predominated before the 15th day while the fungicommunity was prosperous afterwards. In conclusion, the compostingmicroorganism community was thrifty before the 27th day, but ran downafterward.