Lubricating oil (LO) is manufactured in various formulations for different applications. The inappropriate disposal of petroleum hydrocarbons can increase soil contamination, promoting deleterious environmental and human health impacts. More specifically, following prolonged exposure, LO contaminants are known to have carcinogenic and neurotoxic effects in humans. Bioremediation provides an effective and attractive strategy to expedite the clean-up processes of LO contaminants. We isolated and identified environmentally adapted strains of Pseudomonas aeruginosa, Pseudomonas putida, and Proteus vulgaris from Houston watershed bayou soils. Interestingly, all three exhibited increased resistance, vis-a-vis surrogate strains, to various antibiotic challenges (of chloramphenicol, tetracycline, kanamycin, penicillin, streptomycin, etc.) and increased biofilm formation ranging from 1.6 to 6.7-fold. In fact, all three environmental strains were significantly better at producing enhanced biofilm formation in the presence of spent LO rather than clean LO as well as outproducing biofilm made by the surrogate strains. Finally, the environmental isolates P. aeruginosa, P. putida, and P. vulgaris demonstrated an enhanced ability to sequester clean (2-, 2.5- and 1.14-fold) and spent (1.4-, 1.5, and 1.2-fold) LO when compared to their commercially acquired surrogate reference strains. Our three environmentally isolated organisms from Houston watershed soils appeared to be environmentally adapted to tolerate LO exposures. In the presence of LOs, all three environmentally isolated strains exhibited enhanced growth, enhanced biofilm production, and improved bioaccumulation of LOs relative to commercial reference strains. Taken together, environmentally adapted organisms can promote the bioremediation of contaminants threatening our environment and, potentially, human health.
Mosquera et al. (Thu,) studied this question.