Study On Bacterial Community Of Anaerobic Granular Sludge In Indusrial Antibiotic Wastewater Treatment

Anaerobic granular sludge is the key of the anaerobic treatment reactor operation effectively and steadly.The study on bacterial population of anaerobic granular sludge is important to direct and improve the anaerobic wastewater treatment operation.In order to investgate the effects of antibiotic wastewater on bacterial population in the anaerobic granular sludge,the anaerobic granular sludge samples were taken from several full-scale wastewater treatment reactors in Shijiazhuang and the bacterial population diversity of these samples were compared based on PCR-DGGE analysis.Some key steps of PCR-DGGE were improved according to the properties of these sludge samples.Some indices,including Shannon index(H'),Margalef index(D_Mg) and Berger-Parker dominance index(d),were measured by analyzing data of DGGE band patterns and compared comprehensively to evaluate bacterial population diversity of sludge samples. Based on the known density of genetically engineered microorganism,the densites of dominant bacterial populations of the sludge samples were calculated.The results were shown as follows.According to the characteristics of sludge samples from full-scale wastewater treatment bioreactors,a general total DNA extraction method for industrial wastewater treatment anaerobic sludge samples was obtained by improving the lysozyme-SDS-phenol/chloroform method The conditions of PCR and DGGE were optimized and the optimum conditions in these experiments were determined.The touchdown PCR reaction and GC-clamp on the primer BSF338 were selected in PCR.The electrophoresis was conducted at 60 V for 12.5 h and the gel was stained with EB in DGGE.Wastewater characteristics would come into being environment screening effect which affected evidently the bacterial population diversity of anaerobic granular sludge samples.The sludge samples treating fermentation wastewater,especially antibiotic wastewater,showed lower diversity and higher dominance than that treating municipal wastewater.The bacterial community diversity of granule sludge samples seemed higher than that of floc sludge samples.The operation environment of pilot-scall bioreactors were simpleness and stability,which would enhance envrionment screening effect.As a result, the sludge sample from a pilot-scale anaerobic reactor treating synthetical antibiotic wastewater had lower diversity and much higher dominance than that from industrual reactor treating real antibiotic wastewater. The dominant bacterial population densities of the sludge samples were calculated according to known density of genetically engineered microorganism based on DGGE band patterns.The results indicated that the bacterial population with larger than 10⁴ cfu·mL^-1 could only be detected by DGGE.