One of the major environmental problems today is hydrocarbon contamination resulting from the activities related to the petrochemical industry. Accidental releases of petroleum products are of particular concern in the environment. Hydrocarbon components have been known to belong to the family of carcinogens and neurotoxic organic pollutants. Currently accepted disposal methods of incineration or burial insecure landfills can become prohibitively expensive when amounts of contaminants are large. Mechanical and chemical methods generally used to remove hydrocarbons from contaminated sites have limited effectiveness and can be expensive. Bioremediation is the promising technology for the treatment of these contaminated sites since it is cost-effective and will lead to complete mineralization. Bioremediation functions basically on biodegradation, which may refer to complete mineralization of organic contaminants into carbon dioxide, water, inorganic compounds, and cell protein or transformation of complex organic contaminants to other simpler organic compounds by biological agents like microorganisms. Many indigenous microorganisms in water and soil are capable of degrading hydrocarbon contaminants. This paper presents an updated overview of petroleum hydrocarbon degradation by microorganisms under different ecosystems.

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Microbial Degradation of Petroleum Hydrocarbon Contaminants: An Overview

Increasing public awareness of environmental pollution influences the search and development of technologies that help in clean up of organic and inorganic contaminants such as hydrocarbons and metals. An alternative and eco-friendly method of remediation technology of environments contaminated with these pollutants is the use of biosurfactants and biosurfactant-producing microorganisms. The diversity of biosurfactants makes them an attractive group of compounds for potential use in a wide variety of industrial and biotechnological applications. The purpose of this review is to provide a comprehensive overview of advances in the applications of biosurfactants and biosurfactant-producing microorganisms in hydrocarbon and metal remediation technologies.

https://www.mdpi.com/1422-0067/12/1/633/pdf

Environmental applications of biosurfactants: Recent advances

Biosurfactants are surface-active biomolecules produced by microbes (bacteria, fungi, and yeast) and have several advantages over the chemical surfactants, such as lower toxicity, higher biodegradability, better environmental compatibility, higher foaming, high selectivity, and specific activity under extreme conditions such as temperature, pH, and salinity. Almost all the surfactants now available in the market are chemically synthesized. Recently, attention toward the biosurfactants was doubled, which is mainly due to their wide range of functional properties and the diverse synthetic capabilities of the microbes. Microbial biosurfactants are found to have a wide range of applications in environmental protection, which include enhancing oil recovery, controlling oil spills, biodegradation, and detoxification of oil-contaminated industrial effluents and soils. Biosurfactants produced by microorganisms have potential applications in pharmaceutical/medicine, food, cosmetic, pesticide, oil, and biodegradati...

Biosurfactant Producing Microbes and their Potential Applications: A Review

Excessive use of pesticides and herbicides is a major environmental and health concern worldwide. Atrazine, a synthetic triazine herbicide commonly used to control grassy and broadleaf weeds in crops, is a major pollutant of soil and water ecosystems. Atrazine modifies the growth, enzymatic processes and photosynthesis in plants. Atrazine exerts mutagenicity, genotoxicity, defective cell division, erroneous lipid synthesis and hormonal imbalance in aquatic fauna and nontarget animals. It has threatened the sustainability of agricultural soils due to detrimental effects on resident soil microbial communities. The detection of atrazine in soil and reservoir sites is usually made by IR spectroscopy, ELISA, HPLC, UPLC, LC–MS and GC–MS techniques. HPLC/LC–MS and GC–MS techniques are considered the most effective tools, having detection limits up to ppb levels in different matrices. Biodegradation of atrazine by microbial species is increasingly being recognized as an eco-friendly, economically feasible and sustainable bioremediation strategy. This review presents the toxicity, analytical techniques, abiotic degradation and microbial metabolism of atrazine.

Toxicity, degradation and analysis of the herbicide atrazine

The degree of polycyclic aromatic hydrocarbon contamination of environmental matrices has increased over the last several years due to increase in industrial activities Interest has surrounded the occurrence and distribution of polycyclic aromatic hydrocarbons for many decades because they pose a serious threat to the health of humans and ecosystems The importance of the need for sustainable abatement strategies to alleviate contamination therefore cannot be overemphasised, as daily human activities continue to create pollution from polycyclic aromatic hydrocarbons and impact the natural environment Globally, attempts have been made to design treatment schemes for the remediation and restoration of contaminated sites Several techniques and technologies have been proposed and tested over time, the majority of which have significant limitations This has necessitated research into environmentally friendly and cost-effective clean-up techniques Bioremediation is an appealing option that has been extensively researched and adopted as it has been proven to be relatively cost-effective, environmentally friendly and is publicly accepted In this review, the physicochemical properties of some priority polycyclic aromatic hydrocarbons, as well as the pathways and mechanisms through which they enter the soil, river systems, drinking water, groundwater and food are succinctly examined Their effects on human health, other living organisms, the aquatic ecosystem, as well as soil microbiota are also elucidated The persistence and bioavailability of polycyclic aromatic hydrocarbons are discussed as well, as they are important factors that influence the rate, efficiency and overall success of remediation Bioremediation (aerobic and anaerobic), use of biosurfactants and bioreactors, as well as the roles of biofilms in the biological treatment of polycyclic aromatic hydrocarbons are also explored

http://digitalknowledge.cput.ac.za/bitstream/11189/6185/1/Alegbeleye_OO_Opeolu_BO_Jackson_VA_AppSci_2017.pdf

Polycyclic Aromatic Hydrocarbons: A Critical Review of Environmental Occurrence and Bioremediation.

Pseudomonas sp. strain LP1, an organism isolated on the basis of its ability to grow on pyrene, was assayed for its degradative and biosurfactant production potentials when growing on crude, diesel and engine oils. The isolate exhibited specific growth rate and doubling time of 0.304 days−1 and 2.28 days, respectively on crude oil (Escravos Light). The corresponding values on diesel were 0.233 days−1 and 2.97 days, while on engine oil, were 0.122 days−1 and 5.71 days. The organism did not show significant biosurfactant production towards crude oil and diesel, but readily produced biosurfactant on engine oil. The highest Emulsification index (E24) value for the biosurfactant produced by LP1 on engine oil was 80.33 ± 1.20, on day 8 of incubation. Biosurfactant production was growth-associated. The surface-active compound which exhibited zero saline tolerance had its optimal activity at 50°C and pH 2.0.

Degradation of hydrocarbons and biosurfactant production by Pseudomonas sp. strain LP1

Crude Oil Degradation by Microorganisms in Soil Composts

The growth rates and pyrene degradation rates of Pseudomonas sp. LP1 and Pseudomonas
 aeruginosa LP5 were increased in corn steep liquor (CSL) supplemented. On pyrene alone the highest specific growth rate of LP1 was 0.018 h−1, while on CSL-supplemented pyrene MSM, the value was 0.026 h−1. For LP5 the highest growth rate on CSL-supplemented pyrene-MSM was 0.034 h−1. Conversely, on pyrene alone the highest rate was 0.024 h−1. CSL led to marked reduction in residual pyrene. In the case of Pseudomonas sp. LP1 values of residual pyrene were 58.54 and 45.47%, respectively, for the unsupplemented and supplemented broth cultures, showing a difference of 13.09%. For LP5 the corresponding values were 64.01 and 26.96%, respectively, showing a difference of 37.05%. The rate of pyrene utilization by LP1 were 0.08 and 0.11 mg l−1 h−1 on unsupplemented and supplemented media, respectively. The corresponding values for LP5 were 0.07 and 0.015 mg l−1 h−1, respectively. These results suggest that CSL, a cheap and readily available waste product, could be very useful in the bioremediation of environments contaminated with pyrene.

Effects of corn steep liquor on growth rate and pyrene degradation by Pseudomonas strains.

Establishment and characterization of atrazine degrading cultures from Nigerian agricultural soil using traditional and Bio-Sep bead enrichment techniques

Atrazine-degrading microorganisms designated EAA-3 and EAA-4, belonging to the genus Nocardioides, were obtained from an agricultural soil in Nigeria. The degradation kinetics of the two strains revealed total disappearance of 25 mg l−1 of atrazine in less than 72 h of incubation at the rate of 0.42 mg l−1 h−1 and 0.35 mg l−1 h−1, respectively. Screening for atrazine catabolic genes in these organisms revealed the presence of trzN, atzB, and atzC. Other genes, specifically atzA, atzD, and trzD, were not detected. Potential intermediates of atrazine catabolic route such as hydroxyatrazine, desethylatrazine, and desisopropylatrazine were utilized as sources of carbon and energy, while desisopropyl desethyl-2-hydroxyatrazine and desisopropyl-2-hydroxyatrazine were attacked but in the presence of glucose. A soil microcosm study showed that degradation was faster in microcosms contaminated with 13 mg of atrazine per g−1 of soil compared with 480 mg g−1 of soil. In the former, degradation was 10% higher in the ...

A. E. Omotayo

Papers

Degradation of hydrocarbons and biosurfactant production by Pseudomonas sp. strain LP1

Crude Oil Degradation by Microorganisms in Soil Composts

Effects of corn steep liquor on growth rate and pyrene degradation by Pseudomonas strains.

Establishment and characterization of atrazine degrading cultures from Nigerian agricultural soil using traditional and Bio-Sep bead enrichment techniques

Metabolism of Atrazine in Liquid Cultures and Soil Microcosms by Nocardioides Strains Isolated from a Contaminated Nigerian Agricultural Soil