THE ROLE OF PLANTS AND MICROORGANISMS IN BIOREMEDIATION OF PETROLEUM HYDROCARBON CONTAMINATED SOILS

Abstract

Soil pollution by petroleum hydrocarbons is a major global environmental issue. Traditional cleanup methods are costly and often do not work well. This review summarizes what is currently known about how plants and microorganisms help clean up petroleum-contaminated soils. The review looks at how microbes break down hydrocarbons, how plants and microbes interact in the root zone, and the use of biostimulation, bioaugmentation, phytoremediation, and rhizoremediation. Biodegradation depends on environmental factors (pH 5.5-8.8, temperature 15-45°C, C:N:P ratio = 120:10:1) and the activity of certain microbes such as Pseudomonas, Rhodococcus, Mycobacterium, and Arthrobacter. Hydrocarbons become harder to break down in this order: n-alkanes, branched alkanes, monoaromatics, polyaromatics, and asphaltenes. Biostimulation with organic fertilizers can achieve 50-95% degradation, bioaugmentation with microbial consortia 63-84%, and phytoremediation with grasses up to 99%. Using both plants and microbes together is the most effective and affordable method. Success relies on creating good conditions for local microbes, choosing plants with strong root systems, and using specialized microbial consortia.