Use of calcium alginate/biochar microsphere immobilized bacteria Bacillus sp. for removal of phenol in water

Abstract

A highly efficient phenol-degrading bacteria strain, identified as Bacillus cereus (GenBank No:MN784421) by 16S rDNA analysis, was used for phenol treatment in the water. Under the optimal degradation conditions (10% inoculation of the strain suspension into beef extract peptone medium; 35 °C; pH 7.0; 1% NaCl), the bacterial strain provided 97.71% degradation rate within 46 h of treatment. For improving the tolerance of the strain to phenol toxicity, water hyacinth (Eichhornia crassipes) was used as a raw material to produce a biochar under different pyrolysis temperatures. It has been shown that treatment of 1400 mg/L phenol by a combination of a bacterial strain and 0.6% (w/v) biochar prepared at 550 °C can achieve a degradation rate of 99.5% within 60 h of treatment. It has also been shown that inoculated biochar, embedded and immobilized by calcium alginate to form calcium alginate/biochar microbial microsphere (CABMM with 3-4 mm diameter), could greatly improve the tolerance of bacteria to phenol toxicity. At the initial phenol concentration of 1400 mg/L, using of CABMM enables to achieve 99.1% of the phenol degradation over 40 h of treatment.