Diverse alkane hydroxylase genes in microorganisms and environments

Area of Science:

• Environmental microbiology
• Biotechnology
• Genomics

Background:

• AlkB and CYP153 are crucial alkane hydroxylases for aerobic alkane degradation.
• These enzymes are vital for bioremediation of oil-polluted sites and microbial enhanced oil recovery.
• Understanding their natural distribution is essential for optimizing these biotechnological applications.

Purpose of the Study:

• To investigate the distribution of alkB and CYP153 genes in microbial communities.
• To identify novel alkane hydroxylase genes and understand their evolutionary patterns.
• To assess the potential roles of these genes in different environmental niches.

Main Methods:

• Bioinformatic analysis of 3,979 microbial genomes.
• Analysis of 137 metagenomes from terrestrial, freshwater, and marine environments.
• Comparative genomics to identify gene distribution patterns and evolutionary events.

Main Results:

• Hundreds of diverse alkB and CYP153 genes, including novel variants, were identified in bacterial genomes.
• No alkB or CYP153 genes were found in archaeal genomes.
• Distinct distribution patterns of these genes were observed across terrestrial, freshwater, and marine metagenomes.
• Evidence for horizontal gene transfer, gene duplication, and gene fusion was found, contributing to gene diversification.
• Discrepancies between gene distribution in genomes and metagenomes suggest the importance of uncharacterized alkane degraders.

Conclusions:

• AlkB and CYP153 genes are widespread in bacteria, indicating their significant role in natural alkane metabolism.
• Evolutionary mechanisms like HGT and gene duplication have driven the diversification of these genes.
• The distribution patterns highlight the adaptability of alkane degraders to diverse environments.
• Further research into less common or unknown alkane degraders is warranted to fully understand microbial contributions to alkane cycling.