Struction Improvment And Degradation Ability Of The Syntrophic Acetogen Cocultures

The recent interest is focosing on improving the system performance and operation stability of anaerobic biological treatment. Traditional thought deems that the performance of methanogen is the most import limited step of anaerobic digestion process. However, the syntrophic acetogeons plays an important role in the anaerobic biological treatment. It is also the breakthrough of the development of efficient anaerobic biological treatment technology. As the niche of the syntrophic acetogeons is between the acidogenes and methanogens, the function of the syntrophic acetogeons might be another rate-limiting step during anaerobic digestion. The efficiency of the anaerobic biological treatment for hydrogen production can be improved by enhancing acid bacterium group. Nevertheless, the isolation of the limited hydrogen-producing acetogens has restricted the research of highly efficient treatment.The hydrogen-consuming methanogens were added to the syntrophic acetogen cocultures to obtain the pure-cultures of hydrogen-producing acetogens by eliminating the exiting other hydrogen-consuming microbes and to purify the struction of flora. It assists to detect the physiology and ecology characters of the cocultures.The aim of this study is to identify and compare the performance of the syntrophic acetogen coculture. The PCR-DGGE was used to analyse the community structure of the co-culture. The structure was constructed by dosing Methanogens to the co-culture of four group of propionate-oxidating syntrophic acetogen and four group of butyric-oxidating syntrophic acetogen. The co-cultures have been taken from the previous study. The results show that the type strain of propionate acid-oxidating bacteria was Pelotomaculum schinkii HHT, and its associated bacteria contains Clostridium, which belongs to hydrogen spindle bacteria, and Peptococcaceae, which belongs to Peptocossus. The type strain of butanotic acid-oxidating bacteria was Desulfovibrio (Clostridium), and its associated bacteria was Clostridium, which belongs to hydrogen spindle bacteria.Methanosarcina barkeri and Methanospirllum hungatei were typical morphology and significant metabolic characteristics of hydrogen consumption from existing library of strains. They were treated as hydrogen consuming bacteria in structure transformation of the screening syntrophic cocluture. The analysis of metabolic features from the propionic acid groups provided two optimal conditions. The first optimal condions were as: temperature - 37℃, nitrogen assimilation concentration - 750 mg/L, the concentration of propionic acid - 2000 mg/L and pH - 6.5 while the another optimal conditions are as: temperature - 37℃, nitrogen assimilation concentration- 500 mg/L, concentration of propionic acid - 2000 mg/L and pH -` 7.0.