Okoro Chuma Conlette

Department of Biology, Microbiology and Biotechnology, Federal University, Ndufu-Alike, Ikwo, Ebonyi State, Nigeria

*Corresponding Author: Okoro Chuma Conlette, Professor, Department of Biology, Microbiology and Biotechnology, Federal University, Ndufu-Alike, Ikwo, Ebonyi State, Nigeria.

Received: February 21, 2018; Published: April 20, 2018

Citation: Okoro Chuma Conlette. “Substrate Enhanced Biodegradation of Light Crude Oil Sludge by the Resident Methanogens of an Oil Storage Tank Sediment”. Acta Scientific Microbiology 1.5 (2018).

Abstract

Introduction: Biodegradation of hydrocarbons under methanogenic conditions has been widely investigated for a variety of crude oil components but the influence of various substrates during methanogenic biodegradation is scanty in literature.

Objective: The main objective is to evaluate the role of metabolic substrates in methanogenic biodegradation.

Materials and Methods:Methanogenic biodegradation of crude oil sludge was investigated using chemical and molecular approaches.

Results: 16S rRNA gene sequences recovered from the samples revealed significant presence of Marinobacterium (63%), Pseudomonas (3%) alongside with acetotrophic Methanosaeta (16%) and hydrogenotrophic Methanobacterium (5%). The resident microbial community was able to reduce the gravimetric weight of residual oil by 65.5% (with complete degradation of C₅ -C₁₇ n-Alkane fractions) in non-amended samples and 94.13% (with complete degradation of C₅ -C₂₅ n-Alkane fractions) in substrate amended samples during the 60-day incubation period. As biodegradation progressed, acetotrophs consume acetate at the rate of 0.41 Mm/day-1 while hydrogenotrophs consume hydrogen at the rate of 0.59 Mm/day^-1.

Conclusion: Our results showed that the resident methanogenic archaea that dominated the anaerobic microbial community were largely responsible for the anaerobic degradation of hydrocarbons in crude oil sludge and degradation rates were enhanced with substrate amendment. Considering the relatively high number of facultatively anaerobic Marinobacterium and significant presence of Pseudomonas in the sequenced data, we speculate that the bacteria were at least partially responsible for biodegradation of crude oil components potentially acting as syntotrophic organisms with methanogens to convert crude oil to methane.

Keywords:Methanogenic Biodegradation; Acetotrophs; Hydrogenotrophs; Crude Oil Sludge; Syntrophy; Anaerobic Biodegradation

Copyright: © 2018 Okoro Chuma Conlette. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.