Flocculating Properties and Production of the Compound Bioflocculantby Rhizobium Radiobacter F2 and Bacillus Sphaeicus F6

Lixin Li^1,2, Lingyan Feng³, Fang Ma¹, Qianshen Zhao²

(1.State Key Laboratory of Urban Water Resource and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China;2. School of Environment and Chemical Engineering, Heilongjiang University of Science andTechnology, Harbin 150022, China;3. School of Energy and Civil Engineering, Harbin University of Commerce, Harbin 150028, China)



Abstract:

A compound bioflocculant CBF, produced by mixed culture of Rhizobium radiobacter F2 and Bacillus sphaeicus F6, was investigated with regard to its production and flocculating properties. The optimization of the culture medium constituents including carbon source, nitrogen source and C/N ratio, metal ions and ionic strength on CBF production were studied. Flocculating properties of CBF were examined by a series of experiments and CBF had good flocculating activities in kaolin suspension with divalent cations and stable over wide range of pH. Studies of the flocculating properties revealed that the flocculation could be stimulated by cations Ca2+, Mg2+, Fe2+, Al3+ and Fe3+. In addition, it was stable at 4-30 ¡æ in the presence of CaCl₂. It was found to be effective for flocculation of a kaolin suspension under neutral and weak alkaline conditions (pH 7.0-9.0), and flocculating activities of higher than 95£¥ were obtained when the CBF concentrations among 6-14 mg/L at pH 8.0. The results of this study indicate that CBF is a potential replacement of conventional synthetic flocculants and is widely applied in water treatment and downstream processing of food and fermentation industries.

Key words:  compound bioflocculant  ª§Rhizobium radiobacter  Bacillus sphaeicus  ª§ production  flocculating activity

DOI£º10.11916/j.issn.1005-9113.2015.04.003

Clc Number:X172

Fund: