Screening and characterization of a bioflocculant produced by Aeromonas sp.
OBJECTIVE
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. N11. Flocculating activity increased in the presence of K+, Na+, or Ca2+. 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 mgxL(-1), and its activity in kaolin suspension was decreased by only 9.2% after heating at 100 degrees C for 60 min.


CONCLUSIONS
The bioflocculant produced by Aeromonas sp. N11 has strong flocculating activity and high stability, which affords high possibility of its practical use.
Li
Xiao-Ming
XM
College of Environmental Science and Engineering, Hunan University, Changsha 410082, Hunan, China. xmli@hnu.cn
Yang
Qi
Q
Huang
Kai
K
Zeng
Guang-Ming
GM
Liao
De-Xiang
DX
Liu
Jin-Jing
JJ
Long
Wen-Fang
WF
D000333:Aeromonas / Q000378:metabolism*; D003470:Culture Media; D005427:Flocculation; D006863:Hydrogen-Ion Concentration; D007616:Kaolin
D003470:Culture Media; D007616:Kaolin