Abstract:
Bisphenol A (BPA) has been used extensively in industries, thus resulted in widespread contamination and posed potential health threats. This research aimed to develop a technique for increase BPA degradation. The preliminary experiment investigated BPA degradability of five bacterial strains including Methylobacterium sp. NP3, Enterobacter sp. BPR1, Enterobacter sp. BPW5, Bacillus cereus BPW4, and Sphingobium sp. P2 and compared three supplement nutrients including 0.1% peptone, 0.1% glucose, and 0.1% yeast extract. Of the tested bacteria, Bacillus cereus BPW4 had the highest degrading activity and it could degrade over 66% of 5 mg/L BPA. In addition, 0.1% glucose was the most effective supplement nutrient. However, strain BPW4 had lower activity on degrading high BPA concentrations. Therefore, the study increased BPA degrading efficiency of strain BPW4 by immobilizing the cells in natural polymer using entrapment approaches. Cells immobilized in gellan gum and aliginate degraded 37% and 62% of 40 mg/L BPA, respectively. Meanwhile, only 3% and 30% of BPA was removed by uninoculated gel beads and free cells, respectively. In addition, bacterial count in alginate was higher than in gellan gum after 15 days. These results indicated that alginate protected the cells from BPA better than gellan gum and thereby increased BPA degrading activity. The supplement of glucose was also beneficial to the immobilized cells, since they had low BPA degrading activity in CFMM medium without 0.1% glucose. Additionally, alginate-immobilized cells could be used repeatedly for 35 days. Therefore, the immobilized cells along with glucose should be further applied in reactor for BPA treatment