title: Production and characterization of a novel bioflocculant from Bacillus licheniformis.
abstract: 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.
authors.affiliation: Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, People's Republic of China.
authors.forename: Yuyan
authors.initials: Y
authors.lastname: Xiong
authors.forename: Yuanpeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Yi
authors.initials: Y
authors.lastname: Yu
authors.forename: Qingbiao
authors.initials: Q
authors.lastname: Li
authors.forename: Haitao
authors.initials: H
authors.lastname: Wang
authors.forename: Ronghui
authors.initials: R
authors.lastname: Chen
authors.forename: Ning
authors.initials: N
authors.lastname: He
mesh_terms: 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*
chemical_list: D011509:Proteoglycans