Screening a Novel Bioflocculant-Producing Strain B-28 and Its Use for Wastewater Treatment

A bioflocculant-producing bacterium, named B-28, was isolated from contaminative soils by gas oil wastewater and identified as Bacillus sp. according to its morphological, physiological, biochemical properties and the analysis of its 16S rDNA gene sequence. The effects of bioflocculant dosage on flocculating activity in kaolin suspension showed that more than 80% of flocculant activity was observed in the range of 0.5-2.0 ml crude fermentation liquid of strain B-28. And the flocculation activity of MBF-28 varies from approximately 80.3% to 93.5% in the temperature range of 20 to 65°C. Moreover, FT-IR spectra showed hydroxyl, C-H, carbonyl, C-O-C groups were present in the MBF-28 molecule and the mainly effective composition of bioflocculant is polysaccharide with the total content of 73.48% (w/w).The wastewater treatment experiments results indicated that the MBF-28 was efficient for decolorization ratio of 82.44% and the removal rate for Cr⁶⁺ was 52.11%, respectively.