[Control of microbial communities achieved by pH adjustment and its influences on batch treatment of antibiotic wastewater]

Scanning electron microscope (SEM), Fluorescent in-situ hybridization (FISH)-Flow Cytometry (FCM) as well as Biolog method were used to discuss the effect of pH control during the batch treatment on the composition and catabolic diversity of the microbial communities obtained from antibiotic wastewater. The following results were obtained: 1) At the end of batch treatment, the percentages of yeast cells in three cultures amount to 88.20%, 54.43% and 1.75%, respectively, when pH levels are individually maintained at 4-5, 5-6 and 6.5-7.5 throughout three batch experiments. Correspondingly, the percentages of bacterial cells in three cultures increase with the increase of pH levels. 2) No significant differences are found among the catabolic diversity of three cultures while the yeast-predominant culture has slightly less catabolic activities in Biolog FF microplate. 3) When bacteria gradually develop to be the dominant species in the culture, gradually enhanced COD removals of 34.8%, 44.8% and 61.2%, respectively, are achieved.