Changes of Bacterial Communities in Composting by PLFA and DGGE Methods

Microbial community structure is little known at different stages during the composting process due to difficult to culture microbes present in composting. Culture-independent methods including phospholipid fatty acid(PLFA) and denaturing gradient gel electrophoresis(DGGE) had been employed to characterize the changes of bacterial community during the composting of agricultural waste. The results showed that:(1)The structure of microbial community from samples was discrete by the PLFA profile method, which suggested each sample owned independent characteristic pattern, and samples selected were representative. The data was comprehensive to characterize the changes of microbial community structure and much specific to evaluate microbial biomass. However, the species could not be determined by the PLFA profile method.(2)The succession of the bacterial community included at least three different stages, i.e. mesophilic microbial community, thermophilic microbial community and maturation microbial community, by the DGGE method. Also, the result showed the temperature played a key role to changes of microbial community during the composting process.(3)The differences revealed by PLFA profile and DGGE methods indicated that observing biological characteristics in composting with just one method should not be considered absolute. Thus it was necessary to develop different methods to study the changes of microbial community structure during the composting process.