摘要
To isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant. Methods Bacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria. Flocculating activity was used as a measure of the flocculating capability of the bioflocculant. Results A novel bioflocculant-producing bacterium was isolated, which was identified to belong to genus Aeromonas and named as Aeromonas sp. Nil. Flocculating activity increased in the presence of K, Na^＋, or Ca^2＋. The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges, and optimum pHs for it were 3.0, 4.0, and 5.0 with 1 mmol/L K^＋, Ca^＋, and Na^＋ present, respectively. The highest flocculating activities for soil suspension were observed at pH 8.0. The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mg.L-1, and its activity in kaolin suspension was decreased by only 9.2% after heating at 100℃ for 60 min. Conclusion The bioflocculant produced by Aeromonas sp. Nil has strong flocculating activity and high stability, which affords high possibility of its practical use.
To isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant. Methods Bacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria. Flocculating activity was used as a measure of the flocculating capability of the bioflocculant. Results A novel bioflocculant-producing bacterium was isolated, which was identified to belong to genus Aeromonas and named as Aeromonas sp. Nil. Flocculating activity increased in the presence of K, Na^＋, or Ca^2＋. The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges, and optimum pHs for it were 3.0, 4.0, and 5.0 with 1 mmol/L K^＋, Ca^＋, and Na^＋ present, respectively. The highest flocculating activities for soil suspension were observed at pH 8.0. The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mg.L-1, and its activity in kaolin suspension was decreased by only 9.2% after heating at 100℃ for 60 min. Conclusion The bioflocculant produced by Aeromonas sp. Nil has strong flocculating activity and high stability, which affords high possibility of its practical use.
