Abstract: PCR-DGGE method was adopted to study the effects of inoculating exogenous microbial agent on the bacterial community diversity in the process of fresh pig manure high-temperature aerobic composting. Exogenous microbial agent inoculation promoted the composting process, with the high-temperature period being advanced by 2 days than that of non-inoculation. DGGE pattern analysis showed that during composting, the dominant bacteria changed significantly, with the Shannon-Wiener index of bacterial community at different composting periods varied obviously. The sequencing of DGGE-distinguished bands showed that Clostridium stercorarium subsp. thermolacticum sp. was the dominant group in the whole composting process. Uncultured bacteria Bacillus coagulans sp. and Clostridium thermocellum sp. became the main groups on the 10th and 16th day after microbial agent inoculation, while uncultured Firmicutes sp. and delta proteobacterium became the dominant groups on the 5th and 16th days in the treatment non-inoculation, respectively. Un-dominant group Ureibacillus thermosphaericu sp. and uncultured  Silvimonas sp. appeared in the late period of well rotted composting, while uncultured soil bacteria mainly appeared in the initial and high-temperature periods. UPGMC cluster analysis showed that exogenous microbial agent inoculation obviously affected the bacterial community structure in different composting periods, and the main component analysis of DGGE patterns in composting process showed that the bacterial community was mainly affected by the exogenous microbial agent inoculation.

Key words: microbial agent, pig manure, aerobic composting, bacteria, community diversity, denaturing gradient gel electrophoresis (DGGE), winter wheat, elevated CO_2, elevated O₃, DIMBOA, allelochemicals.