Biofilm and Biosurfactant Mediated Aromatic Hydrocarbons Degradation by Marine Bacteria Isolated from Contaminated Marine Environments of Niger Delta

Abstract

Aims: To examine the effects of biofilm and biosurfactant associated cells of marine bacteria isolated from contaminated marine environments of Niger Delta on aromatic hydrocarbon degradation.
 Study Design: Nine treatments and the controls designs were set up in triplicates containing 100 mL of sterile modified mineral basal medium in 250 mL conical flasks supplemented with 50, 100, 200 and 300 ppm of xylene, anthracene and pyrene each and nine marine hydrocarbon degraders; incubated at 24°C for 5 - 7 days. The nine treatments and control set ups designated as ANT1, XYL2, PYR3, ANT4, PYR5, ANT6, XYL7, XYL8, PYR9 and CTRL (without hydrocarbons) were used to examine the effects of biofilm and biosurfactant produced by the marine bacteria on aromatic hydrocarbon degradability.
 Place and Duration of Study: Department of Microbiology, Chukwuemeka Odumegwu Ojukwu University, Uli Nigeria between September, 2014 and August, 2017.
 Methodology: A laboratory scale study was carried on six composite samples of the sediment and water samples from the three studied areas using enrichment, selection, morphological, biochemical, growth effect, emulsification, surface tension, bacterial adherence to hydrocarbon (BATH), salt aggregation (SAT) and microtitre plate biofilm formation tests.
 Results: The findings revealed that the three sampling sites harbour a lot of efficient aromatic degrading bacterial strains belonging to the genera: Providencia, Alcaligenes, Brevundimonas, Myroides, Serratia, and Bacillus able to significantly (P = .05) degrade the aromatic hydrocarbons. Significant positive correlation between biofilm formation and emulsification activity (r = 0.670; P = .05), was observed while surface tension (r = 0.134; P > .05), BATH (r = 0.142; P > .05) and SAT (r = 0.227; P > .05) had no significant positive correlation with biofilm formation.
 Conclusion: Thus, the metabolic traits potentials of these strains could be exploited for in situ bioremediation intervention in the coastal areas of Nigeria.

Evaluation of the characterization and heavy metals remediation potential of biosurfactant produced by Aeromonas hydrophila S62A

“…Bergey's Manual of Determinative Bacteriology was used for the identification of the isolated bacterial strain S62A and on the basis of this manual, the strain S62A was tentatively identified as a member of genus Aeromonas hydrophilia. Several Gram-negative rod -shaped bacterial genera have been implicated, identified and documented as excellent biosurfactant producers (Nalini, and Parthasarathi, 2018;Uba et al, 2018;Araújo et al, 2019;Gomaa and El -Meihy, 2019;Ntshingila et al, 2022) and similar observation was made in this study. The application and suitability of biosurfactants in various industrial areas are depended on their stability against variable or extreme environmental settings of temperature, pH and salinity (Araújo et al, 2019).…”

“…The low CMC value of the biosurfactant observed in this study could be due to its excellent formation and aggregation ability (Guo et al, 2022). This result is lower than the published report of Uba et al (2018) which stated that Bacillus cereus PYR9 had the highest reduction of 22.10 ± 8.9 mN /m in surface tension followed by Serratia marcescens XYL7 with 23.00 ± 8.50 mN /m and Alcaligenes faecalis PYR5 had the least reduction of 26.60 ± 8.90 mN /m. In another study by Ravindran et al (2020), they reported that the CMC from Bacillus subtilis was found to be 10 mg/mL which reduced the surface tension from 69.0 to 30 mN/m and that the decrease in surface tension could be as a result of sensitize biosurfactant from the optimized parameters.…”

“…At the end of the incubation period, the media were centrifuged at 4,000 rpm for 20 min for the removal of cells. The cell free broths (supernatants) were later tested for the production and activity of biosurfactant using screening methods (Uba et al, 2018;Ali et al, 2019).…”

“…The surface tension of the supernatant and the solution of extracted biosurfactant was determined using a capillary tube method at room temperature as described by Uba et al (2018).…”

“…The CMC was determined using different concentrations of the crude biosurfactant (0.05, 0.1, 0.5, 1.0, 1.5, 2.0, 2.5, 5, 7, 10, 15 and 20 mg/ mL) and the surface tension of each concentration was determined using a glass capillary technique as previously described at room temperature after which the CMC of the biosurfactant was then determined (Uba et al, 2018).…”