Abstract

This review explores the integration of metagenomics and metabolic engineering as innovative strategies to enhance biohydrogen production in depleted oil reservoirs. These reservoirs present unique challenges, including high salinity, temperature, and pressure, which hinder the effectiveness of conventional biocatalysts. Metagenomics enables the discovery of novel microbial communities and metabolic pathways inherently suited for biohydrogen production under such extreme conditions. Concurrently, metabolic engineering optimizes these strains to improve biohydrogen production efficiency, stability, and tolerance to reservoir-specific environments. Through a bibliometric analysis, this review also highlights broader research trends in bioengineering and energy recovery, identifying four major areas: metagenomic and metabolic engineering for biohydrogen production, dark fermentation, microbial biodegradation of hydrocarbon to produce biohydrogen, and Bacterial DNA editing for enhanced biohydrogen recovery from depleted reservoir oil well. These findings underscore the field’s shift toward sustainable energy solutions that integrate biological processes with technological innovation. By synthesizing recent advancements in metagenomics, metabolic engineering, and synthetic biology, this review provides a comprehensive framework for developing next-generation biocatalysts, potentially transforming depleted oil reservoirs into viable sources of biohydrogen.