Diversification of Inocula and Its Effect on Biodegradation of Chemicals in Sewage Treatment Plant

Biodegradation is a major means to eliminate chemicals in environment. Sources and bio-characteristics of inocula are the major factors affecting biodegradability of chemicals. Activated sludge and secondary effluent was collected from 6 sewage treatment plants in Guangzhou and Guiyang City and cultivated for isolation of biodegrading bacteria. A total of 64 and 52 strains of bacteria were isolated from the sludge and effluent collected in Guangzhou and Guiyang City, respectively, Aeromonas, Bacillus, and Enterobacter were common strains included in the two groups. Polymerase chain reaction analysis shows that 53-58 and 38-43 bands were detected in the sludge and effluent, respectively, collected from the three sewage treatment plants in Guangzhou City, and 29-42 and 30-42 bands in the sludge and effluent, respectively, collected from the three sewage treatment plants in Guiyang City. They were used as inocula for biodegradation of chemicals. Test of the inocula from 6 different sources biodegrading readily degradable naphthoic acid and hardly degradable 4-nitro benzyl chloride show that they were more or less the same in degrading effect, but they varied in effect of degrading moderately degradable biphenyl and 2,4-dichlorophenol,which displayed inhibitory effects on the inocula. All the findings show that biodegradation of the pollutants is positively related to diversity of the inocula.