Production and characterization of a novel bioflocculant from Bacillus licheniformis.
A bacterium producing an extracellular bioflocculant was isolated from contaminated LB medium and identified as Bacillus licheniformis by 16S rRNA gene sequencing and its biochemical/physiological characteristics. The optimum culture conditions for flocculant production were an initial medium pH of 7.2 and an inoculum size of 4% (vol/vol). The maximum flocculating activity (700 U/ml) was obtained after cultivation at 37 degrees C for 48 h. Chemical analyses of the purified bioflocculant revealed that it was a proteoglycan composed of 89% carbohydrate and 11% protein (wt/wt). The mass ratio of neutral sugar, amino sugar, and uronic acid was measured at 7.9:4:1. Infrared spectrometry further indicated the presence of carboxyl, hydroxyl, and amino groups, typical of heteropolysaccharide. The average mass of the bioflocculant was calculated to be 1.76 x 10(6) Da. Scanning electron microscopy (SEM) images of the bioflocculant showed an irregular structure with netted texture. Its efficient flocculation capabilities suggest potential applications in industry.
Xiong
Yuyan
Y
Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China.
Wang
Yuanpeng
Y
Yu
Yi
Y
Li
Qingbiao
Q
Wang
Haitao
H
Chen
Ronghui
R
He
Ning
N
D001407:Bacillus / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D005427:Flocculation; D008969:Molecular Sequence Data; D011509:Proteoglycans / Q000737:chemistry / Q000378:metabolism*
D011509:Proteoglycans