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Engineered Vibrio natriegens strain boosts bioremediation of complex pollutants in harsh environments

A multi-institutional collaboration of synthetic biology research centers in China has developed a genetically engineered strain of Vibrio natriegens capable of bioremediating complex organic pollutants, including biphenyl, phenol, naphthalene, dibenzofuran, and toluene, in saline wastewater and soils.

Complex organic pollutants are prevalent in industrial wastewater generated by petroleum refining and chlor-alkali processing. Due to their chemical stability and resistance to natural degradation, these compounds persist in marine and saline environments, posing ecological risks and potential threats to public health.

Microbial bioremediation methods typically use consortia of wild-type bacterial strains, yet these organisms demonstrate limited capacity to degrade complex pollutant mixtures. Elevated salinity levels further inhibit bacterial activity, diminishing bioremediation efficacy in industrial and marine wastewater. Developing bacterial strains capable of degrading pollutants while tolerating saline conditions remains a critical challenge.

In the study, "Bioremediation of Complex Organic Pollutants by Engineered Vibrio natriegens," in Nature, researchers employed synthetic biology techniques to engineer Vibrio natriegens to degrade multiple organic pollutants in saline wastewater and soils.

Synthetic degradation gene clusters targeting biphenyl, phenol, naphthalene, dibenzofuran, and toluene were chemically synthesized and assembled in yeast. Gene clusters were subsequently integrated into the Vibrio natriegens Vmax genome and verified through PCR analysis and sequencing to confirm genetic stability and correct orientation.

Engineered Vibrio natriegens VCOD-15 achieved substantial reductions in pollutant concentrations during resting-cell assays conducted in simulated saline wastewater. Biphenyl levels decreased from 189.3 to 0 μM, phenol from 203.1 to 59.6 μM, naphthalene from 185.8 to 52.5 μM, dibenzofuran from 40.6 to 4.3 μM, and toluene from 201.7 to 20.3 μM over a 48-hour treatment period.

Mass spectrometry detected expected degradation intermediates, including catechol, salicylic acid, benzoic acid, and benzyl alcohol. Gene expression assays confirmed consistent transcription of all inserted gene clusters, with sequencing data indicating no off-target modifications.

The engineered strain VCOD-15 presents a potential tool for mitigating toxic pollutants in industrial wastewater, with broader implications for protecting marine ecosystems and public health.

Study authors emphasized the technology's potential, stating, "Our engineered Vibrio natriegens strain offers a powerful platform for the bioremediation of complex organic pollutants in challenging saline environments."