Diversity of Hydrocarbon-Related Catabolic Genes in Oil Samples from Potiguar Basin (Rn, Brazil)

Abstract

Biodegradation may result in physicochemical changes in crude oil and natural gas properties, being responsible for the decrease of saturated hydrocarbons and yielding heavy oil with low economic value. Studies on the diversity of microbial catabolic genes in oil reservoirs are scarce and could help to predict the potential of a petroleum sample to be biodegraded. The aim of this study was to evaluate the diversity of genes involved in hydrocarbon degradation in Brazilian petroleum samples (biodegraded and non-biodegraded) through the construction and analysis of gene libraries (alkane monooxygenase-alk, dioxygenase-ARHDs and 6-oxocyclohex-1-ene-1-carbonyl-CoA hydrolase-bamA). The results showed a differential distribution of catabolic genes between the sites, being the biodegraded oil more diverse for the alk and bamA genes. Sequences were similar to the alkB genes from Geobacillus thermoleovorans and several species of Acinetobacter, to ARHD genes from Pseudomonas spp. and two species of Burkholderia, and to bamA genes from deltaproteobacteria. Interestingly, most of the catabolic sequences recovered from both petroleum reservoirs grouped together forming distinct clusters in the phylogenetic tree reconstruction and may correspond to potentially new genes, possibly harbored by yet uncultivated microorganisms. This is the first report on the detection of alk, ARHD and bamA genes in petroleum reservoir environments, demonstrating the genetic potential of such microbial communities to biodegrade the oil.

Diversity of Metabolically Active Bacteria in Water-Flooded High-Temperature Heavy Oil Reservoir

“…Two phylotypes were closely related to the homologs of the alkB-geo1 (22 out of 43 clones) and alkB-geo6 genes (5 out of 43 clones) (Table S2). The third phylotype (16 clones) exhibited only 84% similarity to the alkB genes of cultured bacteria and 98% similarity to the alkB genes revealed in the microbial community of formation water from production wells at the onshore Potiguar Basin (Northeast, Brazil) (Verde et al, 2013) and of oil exploring area located in the Xinjiang Uygur Autonomous Region (Northwest, China) (Yang et al, 2015). The third phylotype probably belongs to a presently unknown microorganism inhabiting oilfields.…”

Contrasting Distribution of Microbial Communities, Functional Genes, and Antibiotic Resistance Genes in Produced Water Treatment Plants with Different Treatment Technologies

“…Thermus comprises extreme thermophilic microorganisms with the ability to degrade PAH compounds and PAH/alkane mixtures [69]. Hydrogenophilus belongs to the class Betaproteobacteria, which is representative in oil reservoir samples and the members of this class were proven to be the carrier of hydrocarbon degradation functional genes [70]. Schleiferia is a heat-resistant bacterium (30-60 • C) that has not been well investigated at oil contamination sites [71], whereas Amphiplicatus is capable of reducing nitrates and biodegrading organic matter in wastewater.…”

Bioremediation potential of microorganisms derived from petroleum reservoirs

“…Hydrocarbon-degrading microorganisms encompass a long list of genera, including Bacillus, Brevibacillus, Pseudomonas, Acinetobacter, Dietzia, Methylobacterium, and Rhodococcus, among others (von der Weid et al, 2007;da Cruz et al, 2010;Verde et al, 2013;Pacheco et al, 2010). In this scenario, bioremediation has become a suitable alternative, and microbial blends and biosurfactants are already commercialized by some companies around the world (Banat et al, 2010;Zhu et al, 2004).…”