Factors Influencing the Bacterial Bioremediation of Hydrocarbon Contaminants in the Soil: Mechanisms and Impacts

Abstract

The discharge of hydrocarbons and their derivatives to environments due to human and/or natural activities cause environmental pollution (soil, water, and air) and affect the natural functioning of an ecosystem. To minimize or eradicate environmental pollution by hydrocarbon contaminants, studies showed strategies including physical, chemical, and biological approaches. Among those strategies, the use of biological techniques (especially bacterial biodegradation) is critically important to remove hydrocarbon contaminants. The current review discusses the insights of major factors that enhance or hinder the bacterial bioremediation of hydrocarbon contaminants (aliphatic, aromatic, and polyaromatic hydrocarbons) in the soil. The key factors limiting the overall hydrocarbon biodegradation are generally categorized as biotic factors and abiotic factors. Among various environmental factors, temperature range from 30 to 40°C, pH range from 5 to 8, moisture availability range from 30 to 90%, carbon/nitrogen/phosphorous (C/N/P; 100:20:1) ratio, and 10–40% of oxygen for aerobic degradation are the key factors that show positive correlation for greatest hydrocarbon biodegradation rate by altering the activities of the microbial and degradative enzymes in soil. In addition, the formation of biofilm and production of biosurfactants in hydrocarbon-polluted soil environments increase microbial adaptation to low bioavailability of hydrophobic compounds, and genes that encode for hydrocarbon degradative enzymes are critical for the potential of microbes to bioremediate soils contaminated with hydrocarbon pollutants. Therefore, this review works on the identification of factors for effective hydrocarbon biodegradation, understanding, and optimization of those factors that are essential and critical.

Kerosene Biodegradation by Highly Efficient Indigenous Bacteria Isolated From Hydrocarbon-Contaminated Sites

“…Bacteria are the most diverse and ubiquitous groups of microorganisms known to have imperative functions in the bioremediation of hydrocarbon-contaminated environments. 33 , 34 This work used a BHMS medium enriched with 0.5% kerosene to isolate 7 kerosene-degrading bacteria from hydrocarbon-contaminated settings. Population densities ranging from 10 4 to 10 7 CFU per gram of soil were observed at all sampling sites, which is within the recommended range for efficient hydrocarbon biodegradation.…”

An Sustainable Strategy for Reuse Agriculture Soil Impacted by A Mixture of Hydrocarbons

“…In the third biostimulation with vermicompost; nitrogenous organic compounds (N) such as urea and nucleotides; as well as organic carbon compounds (C) such as cellobiose and glucose; were added to induce heterotrophic aerobic microorganisms to co-metabolize WMO hydrocarbons and decrease their concentration [19,13,20] While BIS in sequence with V. sativa or green manure enriched the soil with organic N compounds: peptides and amino acids; to maintain the balance of the C:N ratio; as well as with simple organic C compounds to maintain the cometabolism of WMO hydrocarbons to decrease the concentration of WMO [8]. During soil biostimulation; moisture was retained at 80% of field capacity that facilitated water and gas exchange that accelerated WMO bioremoval [10]; compared to soil not biostimulated or NC; there the concentration of the hydrocarbons mixture of WMO did not vary due to the excess of C; that inhibited the capacity of WMO mineralization by native heterotrophic aerobic soil microorganisms; in addition to the deficit of inorganic and organic N that complicates the possibility of bioremoval of WMO removal [21,22].…”

Different strategies and bio-removal mechanisms of petroleum hydrocarbons from contaminated sites

“…Hydrocarbon metabolism rates were greatly reduced with the increase in salinity. The optimum salinity range for significant petroleum hydrocarbon degradation is 0.1-2M NaCl concentration (Kebede, Tafese, Abda, Kamaraj, & Assefa, 2021).…”

“…Nutrients. Nutrients such as nitrogen, phosphorus, potassium and iron are essential for the successful degradation of petroleum hydrocarbons (Al-Hawash et al, 2018;Kebede et al, 2021). Zafra, Absalon, and Cortes-Espinosa (2015) reported that the high concentration of petroleum hydrocarbons limited the growth of microorganisms.…”