Dynamic Changes of Culturable Microbial Community and Their Degradation Abilities in Thermophilic Stage of Cow Manure Composting
|School||Nanjing Agricultural College|
|Keywords||compost thermophilic bacteria thermophilic actinomyces bacterialcommunity isolation and identificaiton degradation ability|
With the development of stockbreeding industry, manure production of livestock has become a serious social and environmental problem. Because of its economical, convenient, aerobic compost has been the main approach to treat the livestock manure in our country.Aerobic compost is proceeded by microorganisms. The thermophilic stage of composting is very important to the degradation of compost materials. The study aimed to confirm the dynamic change of the culturable microbial community and their degradation abilities of starch, protein and cellulose in thermophilic stage of composting. The results were as following.The the temperature rose to above50℃in three days and compost process entered the thermophilic stage which maintained for about20days. During the composting, the moisture content decreased gradually and reached to about50%at end.The microbial population dynamics showed the trend of" higher-lower-higher". At the beginning of thermophilic stage, the numbers of thermophilic bacteria and actinomyces were107CFU·g-1and106CFU·g-1respectively. As the composting proceeding, the microbial population decreased, the numbers of thermophilic bacteria and actinomyces decreased to106CFU·g-1and104CFU·g-1respectively. At the end of thermophilic stage, as the temperature decreased, the numbers of thermophilic bacteria and actinomyces increased to107CFU·g-1and105CFU·g-1respectively. In general, the population of bacteria was dominant and larger than actinomyces. Fungi were not found at the thermophilic stage (≥50℃)The diversities of bacteria were changed greatly in different time of thermophilic stage. At the beginning of thermophilic stage,124bacterial iaolates were obtained, which belonged to13genera,27species. As the composting proceeding, the bacterial diversity decreased greatly. At the13th when temperature rose to64℃,total36bacterial strains were isolated, which belongde to Bacillus., Geobacillus., Ureibacillus sp., and8species. At the33th which was the end of thermophilic stage and the temperature decreased, the bacterial diversities increased to13species. In general, the bacterial diversity was not rich in thermophilic stage, most of isolates belonged to genera of Bacillus, Geobacillus. and Ureibacillus.Many isolated strains have the degradation ability of starch, protein and cellulose. Strains BA95, BG9, BG35, BG43showed higher degradation ability of starch. The of The strains BB48, BB55, BB51, BC15, BC44, BF39showed higher degradation ability of protein. But only a few bacterial strains have the degradation ability of cellulose. All the isolated showed no antagonistic activity against Ralstonia solanaceaom.