Screening and Culture Condition Optimizing of Microbial Flocculant-Producing Bacterium

Using conventional isolation and purifying methods, eight microbial flocculant-producing bacteria were screened from active sludge of Zhengzhou Wulongkou wastewater treatment plant. One of them was proved to have high flocculating capability through re-screened and was named as the isolate 127#. Selecting the isolate 127# as the research object, the optimal culture medium and culture conditions of this bacterium were established as follows: saccharose 20 g/L, sodium nitrate 1.5 g/L, dipotassium hydrogen phosphate 1 g/L, potassium chloride 0.5 g/L, heptahydrate magnesium sulfate 0.5 g/L, ferrous sulfate 0.01 g/L; pH 12, temperature 30degC, shaker rotate speed 150 r/min, culture time 74 h. Under the optimal culture condition, it has perfect flocculating ability on kaolin suspension. The flocculating ratio was up to 94.98%.