Metabolic specialization and synergy in alkane degradation by a microbial consortium: an integrated genomic and geochemical approach

The constant demand for petroleum and the recurrence of environmental accidents led to the development of sustainable strategies for the treatment of contaminated areas, such as bioremediation. Alkanes, being one of the most abundant and challenging fractions of petroleum in terms of biodegradation, demand microorganisms with high metabolic specialization and the incorporation of bacterial consortia, which possess high efficiency due to inter-species synergy. This study had as its objective to integrate genomic and geochemical analyses to unveil the potential and mechanisms of alkane degradation by nine bacterial strains ( Bacillus, Brevibacillus, Pseudomonas , and Stenotrophomonas ) isolated from a contaminated mangrove. The genomic sequencing and functional annotation revealed the presence of key genes and enzymes associated with alkane activation and oxidation, distributed among different bacterial genera. The geochemical analyses by GC-FID demonstrated the superiority of the complete consortium and the specificity of the strains, with highlight to Pseudomonas and Stenotrophomonas in the rapid degradation of the light and intermediate fractions, and Bacillus in the slower and more efficient degradation of the heavy fractions. Furthermore, the study evidenced the complexity of geochemical data analysis in multiphasic systems, where the negative variations were identified as methodological artifacts resulting from biofilm formation and a consequent heterogeneous sampling. The integration of genomic and geochemical results revealed itself to be a powerful tool to elucidate the microbial interactions and to understand the specific alkane degradation mechanisms of each genus in the bioremediation process.