Metabolic Flux Analysis Reveals Entner–Doudoroff Pathway Dominance in Heterotrophic Deep‐Sea Bacterial Isolates
Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine
ABSTRACT Deep‐sea microorganisms adapt to extreme conditions by diverse metabolic strategies, yet their intracellular carbon fluxes remain largely unexplored. Here, we investigated the central carbon metabolic fluxes of four bacterial strains isolated from Pacific Ocean sediments and deep waters, includingPS1,WP3,WS11 andW43. UsingC metabolic flux analysis with multipleC‐labelled glucose isotopologues, all strains preferentially degraded glucose via the Entner–Doudoroff pathway (EDP) with fluxes accounting for 66.7%–94.0% of total glycolytic flux, indicating that EDP is a conserved and dominant glycolytic route among deep‐sea heterotrophs.WP3 uniquely exhibited substantial flux through both oxidative and non‐oxidative branches of the pentose phosphate pathway, suggesting heightened precursor and redox demands. The strains also displayed diverse anaplerotic strategies, engaging either phosphoenolpyruvate or pyruvate carboxylation to replenish tricarboxylic acid cycle intermediates and enhance carbon utilisation efficiency. Oxidative stress assays further revealed a link between intracellular energy status and tolerance to hydrogen peroxide. Collectively, these findings provide comparative fluxomic evidence for central carbon metabolism in deep‐sea bacteria and highlight metabolic traits that support survival in carbon‐limited, high‐pressure marine environments. Four deep‐sea bacterial strains, isolated from sediments at the water depths of 1–10 km, exhibited diverse metabolic
Abstract
ABSTRACT Deep‐sea microorganisms adapt to extreme conditions by diverse metabolic strategies, yet their intracellular carbon fluxes remain largely unexplored. Here, we investigated the central carbon metabolic fluxes of four bacterial strains isolated from Pacific Ocean sediments and deep waters, includingPS1,WP3,WS11 andW43. UsingC metabolic flux analysis with multipleC‐labelled glucose isotopologues, all strains preferentially degraded glucose via the Entner–Doudoroff pathway (EDP) with fluxes accounting for 66.7%–94.0% of total glycolytic flux, indicating that EDP is a conserved and dominant glycolytic route among deep‐sea heterotrophs.WP3 uniquely exhibited substantial flux through both oxidative and non‐oxidative branches of the pentose phosphate pathway, suggesting heightened precursor and redox demands. The strains also displayed diverse anaplerotic strategies, engaging either phosphoenolpyruvate or pyruvate carboxylation to replenish tricarboxylic acid cycle intermediates and enhance carbon utilisation efficiency. Oxidative stress assays further revealed a link between intracellular energy status and tolerance to hydrogen peroxide. Collectively, these findings provide comparative fluxomic evidence for central carbon metabolism in deep‐sea bacteria and highlight metabolic traits that support survival in carbon‐limited, high‐pressure marine environments. Four deep‐sea bacterial strains, isolated from sediments at the water depths of 1–10 km, exhibited diverse metabolic flux patterns in central carbon metabolism as well as differing antioxidative responses. graphical