Assessing the Effect of Chemical Dispersant Nokomis 3-F4 on the Degradation of a Heavy Crude Oil in Water by a Marine Microbial Consortium

Degradation efficiency of a heavy crude oil by a marine microbial consortium was evaluated in this study, with and without the addition of a chemical dispersant (Nokomis 3-F4). 15.50% of total petroleum hydrocarbons (TPH) were removed after 15 days of incubation without dispersant, with a degradation rate of 2.39 +/- 0.22 mg L-1 day(-1). In contrast, the addition of Nokomis 3-F4 increased TPH degradation up to 30.81% with a degradation rate of 5.07 +/- 0.37 mg L-1 day(-1). 16S rRNA gene sequencing indicated a dominance of the consortium by Achromobacter and Alcanivorax. Nonetheless, significant increases in the relative abundance of Martelella and Ochrobactrum were observed with the addition of Nokomis 3-F4. These results will contribute to further environmental studies of the Gulf of Mexico, where Nokomis 3-F4 can be used as chemical dispersant.