Surfactant addition in diesel oil degradation – how can it help the microbes?

Abstract

Purpose Despite wide research on bioremediation of hydrocarbon-contaminated soil, the mechanisms of surfactant-enhanced bioavailability of the contaminants are still unclear. The presented study was focused on the in-depth description of relationships between hydrocarbons, bacteria, and surfactants. In order to that, the biodegradation experiments and cell viability measurements were conducted, and the properties of cell surface were characterized. Methods MTT assay was employed to measure plant extracts toxicity to microbes. Then, membrane permeability changes were evaluated, followed by diesel oil biodegradation in the presence of surfactants measurements by GCxGC-TOFMS and PCR-RAPD analysis. Results Our study undoubtedly proves that different surfactants promote assimilation of different groups of hydrocarbons and modify cell surface properties in different ways. Increased biodegradation of diesel oil was observed when cultures with Acinetobacter calcoaceticus M1B were supplemented with Saponaria officinalis and Verbascum nigrum extracts. Interestingly, these surfactants exhibit different influences on cell surface properties and their viability in contrast to the other surfactants. Moreover, the preliminary analyses have shown changes in the genome caused by exposure to surfactants. Conclusions The results indicated that the benefits of surfactant use may be related to deep modification at the omics level, not only that of cell surface properties and confirms the complexity of the interactions between bacterial cells, pollutants and surfactants.

Effect of surfactants on the removal of total petroleum hydrocarbons and microbial communities during bioremediation of a contaminated mining soil

“…We attribute that the inhibitory effect of TPH degradation in SDS concentration at 5 CMC may be due to the formation of structural chemical complexes that inhibit microbial growth that affects the biodegradation of TPH, a behavior that has also been reported in studies by Zarei and Fazaelipoor (2022). The inhibitory effect at 9 CMC of Triton X-100 may be due to the dissolution process being affected as well as that the bacterial biodegradation activity probably due to an excess of micelles of the contaminant (Zdarta et al, 2020). Other studies have reported that the addition of Triton X-100 at high concentrations (360 mg/L) to the system with diesel oil affected the hydrophobicity of the cell surface, causing the microorganisms to be unable to adhere to the surface of the hydrocarbon (Kaczorek et al, 2010).…”

Bioengineering for the Microbial Degradation of Petroleum Hydrocarbon Contaminants

“…The common explanation for this question is that biosurfactants can increase the solubility, which can result in higher growth of bacteria and greater efficiency of biodegradation [ 124 ]. However, more-comprehensive analysis of this process has been carried out taking into account multilevel changes occurring in cells from the genome, through metabolic activity, to the surface properties of the cells [ 125 ]. These focused on the in-depth description of relationships between hydrocarbons and bacteria and found changes in the genome caused by exposure to surfactants.…”

Hydrocarbon Degradation and Microbial Survival Improvement in Response to γ-Polyglutamic Acid Application

“…More and more studies focus on supporting the bioremediation process by using various environmentally safe amendments, such as biosurfactants [ 19 , 20 , 21 , 22 , 23 ], or the use of microbial combined methods, including fungi [ 24 , 25 , 26 , 27 ], plants [ 28 , 29 , 30 , 31 , 32 ], algae [ 33 ], biochar [ 34 , 35 ], and biofilms [ 36 ]. γ-polyglutamic acid (PGA) may be one such amendment with great potential for use in the process of pollutant remediation.…”