Complex organic pollutants, such as petroleum and wastewater from oil refineries, are made of aromatic hydrocarbons that pose a substantial risk to ecosystems and human health when released into the environment. Bacteria and microbial consortia can be used to bioremediate seawater and industrial wastewaters contaminated with these compounds. Vibrio natriegens is a promising, generally safe microorganism suitable for use in biotechnology, and for which several engineering tools have been developed. In this study, Su et al. engineered a V. natriegens strain for the remediation of multiple organic pollutants.

The authors selected nine known degradation gene clusters targeting various organic pollutants, including monocyclic pollutants (benzene, toluene and phenol), dicyclic pollutants (naphthalene and biphenyl) and heterocyclic pollutants (dibenzofuran and dibenzothiophene). Each cluster was synthesized in vitro, assembled in the yeast Saccharomyces cerevisiae and then separately inserted and integrated into chromosome 2 of VCOD-2, generating strains VCOD-3 to VCOD-11. In nine-salt solution simulating seawater, only five engineered strains (VCOD-3 to VCOD-7) effectively degraded the target pollutants. These strains were chosen as candidate strains and applied as a synthetic consortium for the bioremediation of complex organic pollutants in vitro for 48 hours, considerably decreasing the concentrations of biphenyl, phenol, naphthalene, dibenzofuran and toluene.