Journal of Environmental Biology

Characterization and flocculation properties of

a carbohydrate bioflocculant from a newly isolated

Bacillus velezensis 40B

Sahar A. Zaki1, Marwa F. Elkady2, Soha Farag1?and Desouky Abd-El-Haleem1*

?Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and

Technological Applications, Alexandria, 21934, Egypt

?Fabrication Technology Department, Advanced Technology and New Materials Research Institute (ATNMRI), City of Scientific Research and

Technological Applications, Alexandria, 21934, Egypt

*Corresponding Author email : abdelhaleemm@yahoo.de

Publication Data

Paper received:

02 November 2011

Revised received:

24 May 2012

Accepted:

26 July 2012

Abstract

In this study, a bioflocculant with a high flocculation activity (>98%) produced by strain 40B, which was isolated from a brackish water was investigated. By 16S rDNA sequence analysis, strain 40B was identified as Bacillus velezensis. Chemical analysis of the bioflocculant 40B indicated that it contained 2% protein and 98% carbohydrates. FTIR analysis showed the presence of carboxyl, hydroxyl and amino groups, which were preferred for the flocculation process. The optimal concentration for the flocculation activity was 3.5 mg l-1. This polysaccharide could also flocculate kaolin suspension over a wide range of pH (1?10) and temperature (5?85 ?C) in the presence of CaCl2. The stability of the bioflocculant 40B under various conditions suggests its possible use in the industries and environmental applications. However, no previous report exists on the isolation and characterization of a bioflocculant from the Bacillus velezensis. ??

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Key words

Bacillus velezensis, Brackish water, Bioflocculant, Stability, Bioflocculant property

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