Bioaugmentation of strain Bacillus sp. hex-HIT36 towards industrial wastewater 1-Hexadecene removal in biological aerated filter reactors

Addressing the technical challenge of high concentrations and low biodegradability of 1-Hexadecene in wastewater generated from petroleum cracking and olefin-based chemical synthesis processes, this study targeted the inoculation of a pre-screened functional strain, Bacillus sp. Hex-HIT36, into a biological aerated filter (BAF) system. The objective was to establish a functional microbial niche dominated by strain HIT36 and systematically investigate its mechanism and efficacy in enhancing the degradation of 1-Hexadecene in chemical wastewater. The removal rate of 1-Hexadecene was 38.1%. After inoculating BAF with 20%, 50%, and 80% of strain HIT36, the removal rates of 1-Hexadecene were 41.8%, 44.8%, and 49.4%, respectively, corresponding to an enhancement of 3.7% to 11.3%. Analysis of microbial community dynamics based on 16S rRNA gene amplicon sequencing revealed that Pseudomonadota, Bacteroidota, and Bacillota were the dominant phyla, while Herbivorax, Pseudomonas, and Hydrogenophaga were the predominant genera. Microbial network analysis indicated that bioaugmentation reconstructed microbial interactions in the BAF, marked by a surge in Bacillota from 1.62% to 10.26%. This led to a network dominated by alkene-degrading specialists, which directionally optimized the community's function. Functional prediction analysis indicated a significant increase in the activity of key enzymes involved in aerobic chemoisomerization, nitrate reduction, and hydrogen-containing compound oxidation. KEGG pathway analysis identified carbon and amino acid metabolism as the dominant functional modules. This study elucidates the regulatory mechanism of targeted bioaugmentation on the microbial ecological niche in BAF, providing a theoretical basis and technical paradigm for the directed removal of refractory organic compounds in industrial wastewater treatment. © 2026 Elsevier B.V.