Application of PCR-DGGE to analysis the microbial community structure in nightsoil sludge anaerobic digestion system aggrandized by HBH-II and alkaline pretreatment

The microbial communities in 6 nightsoil sludge samples taken from the beginning and the 8th days of the 3 anaerobic digestion reactors, ie. the original nightsoil sludge (A), adding 0.0075% HBH-II (B) and adding 0.075% HBH-II under initial pH 10(C), were studied using PCR-DGGE technique. The result shows that alkaline pretreatment can change the microbe community structure of nightsoil sludge system clearly. 21 bacterial 16S rDNA sequences were identified. Four of them keeping good coherence between homology analysis and phylogenetic tree, and they are same generic microbe with Acinetobacter, Clostridium and Bacteroidetes; it can not find the contiguous kind in the phylogenetic tree of the rest 17 kinds of dominant bacterium. The combined augmentation effect of alkaline pretreatment and HBH-II can let Clostridium and Bacteroides propagate largely and then become the dominant population in the nightsoil sludge system, and this conclusion explain the reason why the combined effect of alkaline pretreatment and HBH-II can reduce the nightsoil sludge production as well as the marsh gas production of anaerobic digestion nightsoil sludge.