title: Flocculating property of extracellular polymeric substances produced by a biofilm-forming bacterium Acinetobacter junii BB1A.
abstract: Extracellular polymeric substances (EPS) produced by a biofilm-producing bacterium Acinetobacter junii BB1A were characterized. Purified EPS on analysis revealed neutral sugar (73.21 %), uronic acid (10.12 %), amino sugars (0.23 %), α- amino acids (11.13 %), and aromatic amino acids (1.23 %). Infrared spectrometry revealed the presence of hydroxyl, carboxyl, and amide groups. The average molecular weight of the polysaccharide (PS) fraction of EPS was ~2×10(5). Gas liquid chromatography analysis of PS revealed the presence of three main sugar residues, namely, mannose, galactose, and arabinose (molar ratio of 3:1:1). Cation-independent flocculation above 90 % was observed in the pH range of 4-5 with EPS dosage of 30 mgl(-1) at 20 °C. The emulsifying activity of EPS was 66.6 % with toluene, 60 % with n-hexadecane, 53.3 % with olive oil, and least activity of 13.3 % with kerosene. Proteinase K- and trichloroacetic acid-treated EPS showed reduction in flocculation and emulsification, suggesting the significant role of protein component. Energy dispersive X-ray spectroscopy was used to provide direct evidence of biosorption of Co(II), Cd(II), and Hg(II) by EPS.
authors.affiliation: Omics Laboratory, Department of Biotechnology, University of North Bengal, Siliguri, West Bengal 734013, India.
authors.forename: Krishna K
authors.initials: KK
authors.lastname: Yadav
authors.forename: Amit K
authors.initials: AK
authors.lastname: Mandal
authors.forename: Ipsita K
authors.initials: IK
authors.lastname: Sen
authors.forename: Soumyananda
authors.initials: S
authors.lastname: Chakraborti
authors.forename: Syed S
authors.initials: SS
authors.lastname: Islam
authors.forename: Ranadhir
authors.initials: R
authors.lastname: Chakraborty
mesh_terms: D000150:Acinetobacter / Q000737:chemistry / Q000378:metabolism*; D018441:Biofilms; D005110:Extracellular Space / Q000737:chemistry / Q000378:metabolism*; D005427:Flocculation; D008970:Molecular Weight; D011108:Polymers / Q000737:chemistry / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism*; D013052:Spectrometry, X-Ray Emission
chemical_list: D011108:Polymers; D011134:Polysaccharides