Isolation and characterization of microbial diversity in phenanthrene-degrading consortia in a pollution zone in Ciudad del Carmen, Mexico

Abstract

Human health is adversely affected by polycyclic aromatic hydrocarbons. In fossil fuels, phenanthrene is a simple polycyclic aromatic hydrocarbon with elevated carcinogenicity, teratogenicity, mutagenicity, and ecotoxicity. Several bacterial species have been isolated from soil and sediment samples to assess their ability to utilize phenanthrene. The aim of this study was to isolate and characterize microbial diversity in phenanthrene-degrading consortia. Four aerobic bacterial consortia were isolated from both seawater and sediments from Ciudad del Carmen, Mexico. Synthetic seawater was enriched with phenanthrene at a concentration of 100 mg L-1, serving as the growth medium to assess the pollutant’s degradation potential. Bacterial richness was gauged using the 16S rRNA gene. The biodegradation data revealed a range of 58% to 75% phenanthrene degradation within a span of 7 days. The specific microbial growth rate (μ) ranged from 0.015 to 0.031 h-1, and degradation rates (DR) ranged from 0.732 to 1.94 (mg L-1) / h. The most predominant phyla observed were Proteobacteria, Actinobacteria, Bacteroidetes, Cyanobacteria, and Firmicutes. Within the Proteobacteria phylum, the dominant classes were Gammaproteobacteria and Alphaproteobacteria. The primary operational taxonomic units (OTUs) were identified as Alcalinovorax venustensis and Halomonas sp.