The increased use of petroleum products has also led to increased environmental
pollution by petroleum. Crude oil is transported across the oceans as well as overland
in ships or through pipelines. Inadvertent spills and seepage of petroleum products
during storage tanks and transportation is a leading cause of environmental pollution
of both aqueous and terrestrial environments. Over the years has witnessed several
accidental spills; The Prestige oil tanker wrecked northwest of Spain in 2002
released 40,000 tons of oil (Pérez-Cadahía et al. 2007). The Deepwater Horizon
(DwH) oil spill in April 2010 in the Gulf of Mexico, which occurred as a result of an
explosion, released ~4.9 million barrels of crude oil into the Gulf of Mexico before it
was capped in about 3 months. The spilled oil which spread ~450 miles along the
coastline of the Gulf of Mexico is considered to be one of the worst environmental
disasters in the US history (Bell and Gutierrez 2019).
Petroleum hydrocarbons (PH) are recalcitrant environmental pollutants and are a
global hazard, due to its persistent nature and toxicity of certain fractions. It causes
widespread damage to all forms of life, both aquatic and terrestrial animals, from
microbes to fish as well as whales and birds. Damage may be direct or indirect via the
food chain.
While several methods for decontamination including physical and chemical
have been used over the years, investigation of microbial biodegradation of crude
oil has been an area of interest for several decades. There has been a renewed interest
in recent years due to multiple reasons such as increase in oil spills and increased
awareness regarding environmental pollution and the general interest toward use of
green technologies.
Various species of bacteria, fungi, cyanobacteria, and algae are known to be
capable of utilizing petroleum hydrocarbons. Among them, bacteria are considered
the most active agents in bioremediation (Varjani 2017). However, no single bacterial species has been reported to date, which has the capacity to degrade all the
fractions in crude oil.
The need for increased efficiency in the biodegradation process continues to drive
the exploration of novel strains with capacity for PH degradation. The general
strategy is based on screening for indigenous microbes from sites of contamination.
Recent isolations of individual bacteria as well as mixed consortia have been
reported by several investigators in various parts of the world (Al-Dhabaan 2019;
Chettri and Singh 2019; Perera et al. 2019; Wang et al. 2019a).
The degradation of petroleum hydrocarbons by microbes can be observed as a
three-step process—initially the microorganism needs to have access to the hydrocarbon molecules. Here, the solubility of the molecules or other capacities for
gaining access such as secretion of biosurfactants play an important role. The
compounds then need to be adsorbed to the cell surface and transported to the cell
interior followed by enzymatic degradation and metabolism.
11 Microbial Bioremediation of Petroleum Hydrocarbons
265
pollution by petroleum. Crude oil is transported across the oceans as well as overland
in ships or through pipelines. Inadvertent spills and seepage of petroleum products
during storage tanks and transportation is a leading cause of environmental pollution
of both aqueous and terrestrial environments. Over the years has witnessed several
accidental spills; The Prestige oil tanker wrecked northwest of Spain in 2002
released 40,000 tons of oil (Pérez-Cadahía et al. 2007). The Deepwater Horizon
(DwH) oil spill in April 2010 in the Gulf of Mexico, which occurred as a result of an
explosion, released ~4.9 million barrels of crude oil into the Gulf of Mexico before it
was capped in about 3 months. The spilled oil which spread ~450 miles along the
coastline of the Gulf of Mexico is considered to be one of the worst environmental
disasters in the US history (Bell and Gutierrez 2019).
Petroleum hydrocarbons (PH) are recalcitrant environmental pollutants and are a
global hazard, due to its persistent nature and toxicity of certain fractions. It causes
widespread damage to all forms of life, both aquatic and terrestrial animals, from
microbes to fish as well as whales and birds. Damage may be direct or indirect via the
food chain.
While several methods for decontamination including physical and chemical
have been used over the years, investigation of microbial biodegradation of crude
oil has been an area of interest for several decades. There has been a renewed interest
in recent years due to multiple reasons such as increase in oil spills and increased
awareness regarding environmental pollution and the general interest toward use of
green technologies.
Various species of bacteria, fungi, cyanobacteria, and algae are known to be
capable of utilizing petroleum hydrocarbons. Among them, bacteria are considered
the most active agents in bioremediation (Varjani 2017). However, no single bacterial species has been reported to date, which has the capacity to degrade all the
fractions in crude oil.
The need for increased efficiency in the biodegradation process continues to drive
the exploration of novel strains with capacity for PH degradation. The general
strategy is based on screening for indigenous microbes from sites of contamination.
Recent isolations of individual bacteria as well as mixed consortia have been
reported by several investigators in various parts of the world (Al-Dhabaan 2019;
Chettri and Singh 2019; Perera et al. 2019; Wang et al. 2019a).
The degradation of petroleum hydrocarbons by microbes can be observed as a
three-step process—initially the microorganism needs to have access to the hydrocarbon molecules. Here, the solubility of the molecules or other capacities for
gaining access such as secretion of biosurfactants play an important role. The
compounds then need to be adsorbed to the cell surface and transported to the cell
interior followed by enzymatic degradation and metabolism.
11 Microbial Bioremediation of Petroleum Hydrocarbons
265