Microbial succession during a composting process as evaluated by denaturing gradient gel electrophoresis analysis

Microbial succession during a laboratory-scale composting process of garbag e was analysed by denaturing gradient gel electrophoresis (DGGE) combined w ith measurement of physicochemical parameters such as temperature, pH, orga nic acids, total dissolved organic carbon and water-soluble humic substance . From the temperature changes, a rapid increase from 25 to 58 degreesC and then a gradual decrease, four phases were recognized in the process as fol lows; mesophilic (S), thermophilic (T), cooling (C) and maturing (M). The p olymerase chain reaction-amplified 16S rDNA fragments with universal (907R) and eubacterial (341F with GC clamp) primers were subjected to DGGE analys is. Consequently, the DGGE band pattern changed during the composting proce ss. The direct sequences from DGGE bands were related to those of known gen era in the DNA database. The microbial succession determined by DGGE was su mmarized as follows: in the S phase some fermenting bacteria, such as lacto bacillus, were present with the existing organic acids; in the T phase ther mophilic bacillus appeared and, after the C phase, bacterial populations we re more complex than in previous phases and the phylogenetic positions of t hose populations were relatively distant from strains so far in the DNA dat abase. Thus, the DGGE method is useful to reveal microbial succession durin g a composting process.