Metaproteomic Insights into Bioenergy Conversion Enzymes of Bathypelagic Microbial Communities in the South China Sea

Marine
microorganisms inhabiting the bathypelagic zone (1000–4000
m) exhibit distinctive environmental adaptability and serve as a valuable
reservoir of bioenzymes. However, a limited understanding of deep-sea
microbial community composition and metabolic activities hinders the
broad application of their enzymatic potential. In this study, we
employed a metaproteomic approach to investigate the protein profiles
of microbial communities in the bathypelagic layers of the South China
Sea (SCS), and we compared them with the corresponding metagenomic
data. Our findings revealed a strong phylum-level correlation between
metaproteomic and metagenomic datasets, along with a significant enrichment
of proteins associated with inorganic ion metabolism and energy conversion.
Deep-sea microbial communities are characterized by unique dominant
taxa, such as Propionibacteriales, and exhibit diverse strategies
for energy utilization. Notably, we identified several enzymes involved
in energy conversion, including RuBisCO and carbon monoxide dehydrogenase
in Proteobacteria and ammonia monooxygenase in Thaumarchaeota for
carbon fixation. These enzymes catalyze reactions utilizing various
inorganic substrates as energy sources. Additionally, the deep-sea
environment significantly enhanced the expression of methane monooxygenase
in methylotrophs, suggesting that such conditions may promote the
development of methane-utilizing cell factories. This study not only
deepens our understanding of energy conversion mechanisms in deep-sea
microorganisms but also offers valuable enzymatic resources for the
development of novel bioenergy technologies.