BTEX biodegradation using Bacillus sp. in a synthetic hypoxic aquatic environment: optimization by Taguchi-based design of experiments.

This study was conducted to identify the ability of strain PS of Bacillus sp. on BTEX biodegradation process in saline and hypoxic condition. Despite numerous reports that have assessed BTEX biodegradation in saline environments and hypoxic conditions separately, it is the first time that BTEX biodegradation is investigated by considering these two limiting biodegradation conditions simultaneously. Taguchi's design of experiment methodology was applied to evaluate the influence of four factors (BTEX initial concentration, nitrate initial concentration, salinity and cell mass) on BTEX biodegradation. The chemical analyses, carried out with GC, showed that the most effective factors on biodegradation of the BTEX is initial BTEX and nitrate concentration. Cell mass and salinity only slightly influenced on the biodegradation. The 15 mg/L initial BTEX concentration at 5% salinity can be degraded by strain PS of Bacillus sp. at optimum condition containing 200 mg/L nitrate and 3 × 10⁷ cells/mL cell mass after 10 days. [ABSTRACT FROM AUTHOR]