Phylogeny and diversity of alkane-degrading enzyme gene variants in the laurentian great lakes and western atlantic

ABSTRACT Many aquatic environments are at risk for oil contamination and alkanes are one of the primary constituents of oil. The alkane hydroxylase (AlkB) is a common enzyme used by microorganisms to initiate the process of alkane-degradation. While many aspects of alkane bioremediation have been studied, the diversity and evolution of genes involved in hydrocarbon degradation from environmental settings is relatively understudied. The majority of work done to-date has focused on the marine environment. Here we sought to better understand the phylogenetic diversity of alkB genes across marine and freshwater settings using culture-independent methods. We hypothesized that there would be distinct phylogenetic diversity of alkB genes in freshwater relative to the marine environment. Our results confirm that alkB has distinct variants based on environment while our diversity analyses demonstrate that freshwater and marine alkB communities have unique responses to oil amendments. Our results also demonstrate that in the marine environment, depth is a key factor impacting diversity of alkB genes.

Hydrocarbon degradation by a newly isolated thermophilic Anoxybacillus sp. with bioemulsifier production and new alkB genes

In this work, a new thermophilic bacterial strain was isolated and identified asAnoxybacillussp. WJ-4. This strain of WJ-4 can degrade a wide range of hydrocarbons, and production of an oligosaccharide–lipid–peptide bioemulsifier was detected.

Diversity and abundance of <i>n</i>-alkane-degrading bacteria in the near-surface soils of a Chinese onshore oil and gas field

Alkane-degrading bacteria have long been used as an important biological indicator for oil and gas prospecting, but their ecological characteristics in hydrocarbon microseep habitats are still poorly understood. In this study, the diversity and abundance of n-alkane-degrading bacterial community in the near-surface soils of a Chinese onshore oil and gas field were investigated using molecular techniques. Terminal restriction fragment length polymorphism (T-RFLP) analyses in combination with cloning and sequencing of alkB genes revealed that Gram-negative genotypes (Alcanivorax and Acinetobacter) dominated n-alkane-degrading bacterial communities in the near-surface soils of oil and gas reservoirs, while the dominant microbial communities were Gram-positive bacteria (Mycobacterium and Rhodococcus) in background soil. Real-time quantitative polymerase chain reaction (PCR) results furthermore showed that the abundance of alkB genes increased substantially in the surface soils above oil and gas reservoirs even though only low or undetectable concentrations of hydrocarbons were measured in these soils. The results of this study implicate that trace amounts of volatile hydrocarbons migrate from oil and gas reservoirs, and likely result in the changes of microbial communities in the near-surface soil.