Petroleum biodegradation

BIOREMEDIATION

JOSCEL P. ENARDECIDO

PETROLEUM BIODEGRADATION

Terminologies Defined:• Petroleum- a naturally occuring

flammable liquid consisting of a complex mixture of hydrocarbons that are found in geologic formations beneath the earth’s surface.

Aliphatic Hydrocarbons- any large class of organic compounds whose carbon atoms are joined in straight chains rather than in rings.

• Interface - part where oil and water meet often occur in large scale.

• Bioremediation- refers to the process of using microorganisms in cleaning up oil spills and other pollutants.

• Bioaugmentation- introduction of microorganisms to augment the process.

• Biostimulation- addition of nutrients and oxygen to stimulate the growth of indigenous microorganisms.

Components of petroleum• Hydrocarbons- main component of

Petroleum;

Characteristics of Oil1.Less dense than water , so it floats

forming slicks;2.Insoluble in Water

PRINCIPLES OF BIOREMEDIATION

• Bioremediation uses microorganisms and other living organisms to transform organic pollutants into less toxic forms.

• Biodegradation is the initial process that results to bioremediation.

FACTORS IN BIOREMEDIATION1. Existence of a microbial population

capable of degrading the pollutants;2. The availability of contaminants to the

microbial population e.g. oil3. The environment factors (type of soil,

temperature, pH, the presence of oxygen or other electron acceptors, and nutrients).

MICROBIAL POPULATIONS FOR BIOREMEDIATION PROCESSES

Availability Microbes can be:1.Indigenous- microorganisms are present in

the contaminated site. Biostimulation is needed.

2.Bioaugmentation- introduction of microorganisms from other environment.

Bioremediation in Large Scale

• Gasoline tanks are potential habitats for Hydrocarbon-oxidizing bacteria which can grow in oil-water interface.

HYDROCARBON DEGRADATIONHYDROCARBON DECOMPOSERS:1.Hydrocarbonoclastic Bacteria ( HCB)

- Gammaproteobacteria ( Alcanivorax sp., Marinobacter)- Alphabacteria

(Rhodobacteriaceae)-Pseudomonas, Alcaligenes, Sphingomonas, Rhodococcus, and Mycobacterium.

Hydrocarbon Oxidizing Bacteria Attach to oil slicks

Microbes in Slick Microbes eating gulf oil

Pseudomonas sp.• rod - A gram-negative

enteric rod that are able to grow in extreme environments. Commonly isolated in areas where hydrocarbons are present.

• Fungi - Aspergillus sp.- Mucor sp.- Talaromyces sp.

Green Algae- cyanobacteria

KEY POINTS IN HYDROCARBON DECOMPOSITION

Hydrocarbon decomposition is done by hydrocarbon-oxidizing microorganisms.

The Process occurs in the presence of oxygen.

Microorganisms participate in oil spill cleanup by oxidizing the oil to Carbon Dioxide.

Some factors that hasten up the process:1. pH 3. inorganic nutrients2. Temperature

Inorganic Nutrients such as Phosphorus and Nitrogen are important to stimulate microorganisms.

Evidences of Petroleum Degradation by Microorganisms

• Dispersal of oil slicks ;• Radioisotopic Hydrocarbons as trackers of

Oxygen uptake;• Fungi bloom is evident if enough sources

of food is present; however , when food sources are continously decreasing, the growth of fungi also decreases.

• Presence of less toxic forms of contaminants.

Case Report:March 1989- 11-million-gal oil spill

from a tanker Exxon Valdez devastated the shores near Prince William Sound in Alaska.

The input of this oil spill has devastating effects both environmentally and economically.

Petroleum ProductionAside from the petroleum degradation,

microorganisms also aids in petroleum production.

Botryococcus braunii – a colonial alga is said to excrete long-chain hydrocarbons with 30 to 36 Carbon atoms.

It is considered to be a renewable source of petroleum.

“Bioremediation is not only about genetics and enzymology but also about physiology and ultimately ecology.”—de Lorenzo V:

Systems biology approaches to bioremediation. Curr Opin Biotechnol

2008, 19:579-589.

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Evaluation: ¼ sheet of yellow paper

1. Why might the addition of Phosphorus and Nitrogen stimulate oil degradation while adding of glucose might not? (5pts)

2. Microorganisms can thrive anywhere, what is the reason why microorganisms do not degrade gasoline in storage tanks? (5pts)