The microbial degradation of 2,4,6-tribromophenol (TBP) in water/sediments interface: Investigating bioaugmentation using Bacillus sp. GZT.

The substance 2,4,6-Tribromophenol (TBP) is used as a flame retardant in electronic and electric devices, and is a replacement for pentachlorophenol in wood preservation. TBP is a contaminant in different environmental matrices, at levels where treatment is required. This study examined the relationship between the bioaugmention of TBP degradation and the evolution of the microbial community in river water/sediment microcosms. When compared with unamended controls, bioaugmentation with Bacillus sp. GZT effectively enhanced TBP biodegradation, with approximately 40.7% of the TBP removal after a 7-week incubation period, without a lag phase (p<0.01). Amendments with 2-bromophenol, 2,6-dibromophenol, and 2,4-dibromophenol did not promote TBP biodegradation in river water/sediments (p>0.05). However, TBP biodegradation was enhanced by adding other additives, including NaCl, humic acid, sodium lactate, and sodium propionate alone, especially glucose and yeast extract. A metagenomics analysis of the total 16S rRNA genes from the treatment system with bioaugmentation showed that four microbial phyla were dominant: Proteobacteria (52.08-66.22%), Actinobacteria (20.03-5.47%), Bacteroidetes (6.68-13.68%), and Firmicutes (4.53-20.83%). This study highlights the possible benefits using bioaugmentation with GZT to remediate TBP-polluted water and sediments.