Pseudomonas fluorescens: A Bioaugmentation Strategy for Oil-Contaminated and Nutrient-Poor Soil

Abstract

Bioremediation technology is one of the most profitable and sustainable strategies for remediating soils contaminated with hydrocarbons. This study focuses on assessing the influence of biostimulation and bioaugmentation with Pseudomonas fluorescens to contribute to the removal of total petroleum hydrocarbons (TPHs) of a soil. Laboratory studies were carried out (measurements of emitted CO2, surface tension, and residual TPH) to select the best bioaugmentation and biostimulation treatment. The sources of C, N, and P were glucose–yeast extract, NH4Cl–NaNO3, and K2HPO4–K3PO4, respectively. The effect of culture conditions on the reduction of TPH and respiratory activity was evaluated through a factorial design, 23, in a solid culture system. After 80 days of incubation, it was observed that treatments of yeast extract–NH4Cl–K2HPO4 (Y4) and glucose–NaNO3–K3PO4 (Y5) presented a higher level of TPH removal (20.91% and 20.00% degradation of TPH, respectively). Biostimulation favors the production of biosurfactants, indirectly measured by the change in surface tension in the soil extracts. The treatments Y4 and Y5 showed a lower change value of the surface tension (23.15 and 23.30 mN·m−1 at 25 °C). A positive correlation was determined between the change in surface tension and the removal of TPH; hence there was a contribution of the biosurfactants produced to the removal of hydrocarbons.

Comparative Genomic Analysis of Three Pseudomonas Species Isolated from the Eastern Oyster (Crassostrea virginica) Tissues, Mantle Fluid, and the Overlying Estuarine Water Column

“…Some questions remained unanswered in the previous report, such as other genomic mechanisms by which these strains resist pollutants and engage in biodegradative functions, as well as how their biodegradative genes have evolved relative to other pseudomonads. Given that Pseudomonas spp., are well documented to possess a high metabolic activity and potential for hydrocarbon degradation, and can resist a variety of contaminants in diverse environmental habitats [59][60][61], we queried the genomes of the isolated strains in RAST; the total genes for metabolism of aromatic compounds (in parenthesis) are as follows: Pseudomonas alcaligenes OT69 (64), Pseudomonas stutzeri MF28 (77) and Pseudomonas aeruginosa WC55 (153), respectively. We previously reported that P. aeruginosa strain WC55 showed the highest utilization of crude oil in lab-controlled microcosm studies, relative to the other two strains [31], which is consistent with the highest number of xenobiotic genes identified in strain WC55.…”

Bioremediation approaches for oil contaminated soils in extremely high-mountainous conditions

“…With the combined methods, the acclimatisation of the inoculant might have failed. Thus, much as both biostimulation and bioaugmentation are known to increase the efficiency of soil cleansing processes from oil products, the choice of the appropriate method depends on the environmental conditions as professed by Gutiérrez et al (2020). Taking into account the costly methods of enrichment of the decomposer and their inoculation, we believe that the use of biostimulation in such difficult climatic conditions is the most appropriate.…”

Alfalfa (Medicago Sativa L.): Genotypic Diversity and Transgenic Alfalfa for Phytoremediation

“…In this context, oil is known to be effectively utilized not only by bacteria but also by fungi. Therefore, most studies focus on assessing the influence of petroleum remediation with the most frequent bacterial species of Pseudomonas fluorescens (Gutiérrez et al, 2020), Pseudomonas aeruginosa (Wang et al, 2017;Dobler et al, 2020;Varjani et al, 2020;Varjani and Upasani 2021), and Bacillus subtilis (Montagnolli et al, 2015;Chen et al, 2017;Wang et al, 2019), and some fungi, including Candida and Yarrowia, have a great potential for phytoremediation (Salam et al, 2017;Cecchi et al, 2021). Some review studies recommend the use of fungi for petroleum phytoremediation since fungi are capable of utilizing a wider spectrum of hydrocarbons, element cycling, bioweathering, and mycogenic mineral formation (Deng and Cao 2017).…”