Catabolic Genes for Biodegradation of Total Petroleum Hydrocarbons & Characterization of Microbial Diversity in oil-contaminated soil

Research Proposal On:

Catabolic Genes for Biodegradation of Total Petroleum Hydrocarbons & Characterization of Microbial Diversity in oil-contaminated soil

INTRODUCTION

Octadecane (C₁₈), Eicosane (C₂₀) & Docosane (C₂₂) are petroleum hydrocarbons. In the environment these hydrocarbons enter through waste disposal, accidental spills, leakage tanks, & losses during transportation. These types of hydrocarbons are hazardous to the plants, animals & human. Especially, higher hydrocarbons are more carcinogenic, mutagenic & potent immune-toxicants. The contamination of these hydrocarbons in the environment creates imbalance in the ecosystem.

Microorganisms can utilize petroleum hydrocarbon as a sole source of carbon & energy. Biodegradation is the most effective technique to remove the pollutant such as total petroleum hydrocarbon from environment specifically when bacteria are involved. Natural bacteria present in the contaminated site have the potent ability to degrade such hydrocarbons. Some usually occurring bacteria in the polluted site are Rhodococcus, Pseudomonas, Acinetobacter, Burkholderia, Gordonia  & Enterobacteria.

Every indigenous microorganisms isolated from oil-contaminated soil has certain ability to utilize petroleum hydrocarbons. To evaluate their ability to degrade target pollutants is the most important steps in bioremediation technique. Similarly, time estimation of complete degradation of environmental pollutant from natural sites has another critical role in designing strategy for biodegradation. Monitoring & prediction of biodegradation also has important aspect in the field of cleaning environment from petroleum hydrocarbons.

Molecular Microbiology techniques have revolutionized microbial ecology by developing culture-independent assessment and exploitation of microbial communities present in complex ecosystems like crude-oil/hydrocarbons polluted soil. The combination of PCR-amplification of metagenomic DNA, microbial community profiling techniques & identification of catabolic genes are ways to elucidate the composition, function & interaction of microbial communities during bioremediation.

Cytochrome p450 alkane hydroxylase, di-iron methane monooxygenase, di-iron alkane hydrolases are important group of enzymes that play essential roles in the biotransformation of many environmental pollutants. The detection of these genes encoding these enzymes are important biomarker that indicates metabolic activity in the biological system. Biomarker provides valuable information to assess whether changes in contaminants concentration are occurring through physical, chemical or biological proceses.

On the other hand, applications of genetically engineered microorganisms (GEMs) in bioremediation have received a great deal of attention to improve the degradation of hazardous wastes under lab conditions. The use of genetically engineered bacteria have been applied to bioremediation process monitoring, strain monitoring, stress response, end-point analysis & toxicity assessment. Several species of Pseudomonas, Bacillus and Acinetobacter can be genetically engineered for assessing biodegradation process.

This research will mainly focuses on to detect catabolic genes especially regarding to alkane monooxygenase for assessing & predicting the biodegradation process and characterize bacterial population in using molecular marker in oil-contaminated soil.

OBJECTIVES

·         To detect catabolic gene (Alkane monooxygenase encoding) expressed during biodegradation of total petroleum hydrocarbons.

·         To characterize microbial diversity in petroleum hydrocarbon contaminated soil by using possible biomarkers.

·         To determine probable period of hydrocarbons degradation based on catabolic gene expression rate.

Fig: Work Flow for Determining functional genes & bacterial population

EXPECTED OUTCOMES:

Catabolic Genes are promising molecular markers for assessing completion of biodegradation. Identification of monooxygenase gene during the growth of bacteria in hydrocarbon containing medium and oil-contaminated soil serves as the rapid tool for designing biodegradation program.

This study aims to find alkane monooxygenase encoding genes which are expressed during biodegradation. The precise characterization of bacterial diversity in contaminated soil using molecular tools will be fruitful in future application of these bacteria in contaminated sites. Determining gene expression rate in this study may forecast for possible time frame of completion of biodegradation in natural sites.

REFERENCES:

Gedalanga PB, Pornwongthong P, Mora R, Chiang SYD, Baldwin B, Ogle D, Mhendra S. 2014. Identification of Biomarker Genes To Predict Biodegradation of 1,4-Dioxane. Appl. Environ. Microbiol. 80:3209-3218. http://dx.doi.org/10.1128

/AEM.04162-13.

Chikere CB. 2013. Application of Molecular Microbiology techniques in Bioremediation of Hydrocarbons and other Pollutants. British Biotechnol.  J. 3(1): 90-115.

Das N. Chandran P. 2011. Microbial Degradation of Petroleum Hydrocarbon Contaminants: An Overview. Biotechnol. Res.  Int. 2011;2011:941810. doi: 10.4061/2011/941810.

-2016 May 11