Purple Phototrophic Bacteria as a Novel Platform for Coenzyme Q10 Production from CO2, Syngas, and Sulfur Waste Byproducts

Abstract

The efficient conversion of CO2 and industrial waste streams into value-added products remains a critical challenge for sustainable microbial processes. Here, we present the first systematic demonstration of purple phototrophic bacteria (PPB) as platforms for the autotrophic valorization of CO2 and industrial off-gases or sulfur byproducts into valuable metabolites. Genome-guided screening combined with experimental validation identified strains capable of coupling photoautotrophic growth with the production of CoQ10 and carotenoid pigments. Among them, Rhodospirillum rubrum DSM 467 and DSM 107 exhibited the highest performance, maintaining stable CO2 and H2 consumption under semicontinuous operation and accumulating up to 9.6 ± 0.2 mgCoQ10 gbiomass–1 under CO2/ H2 conditions, comparable to engineered production systems. In addition, R. rubrum DSM 467 efficiently oxidized CO from syngas via the water–gas shift reaction, displaying hierarchical substrate utilization driven by energetic constraints. In contrast, Marichromatium purpuratum simultaneously oxidized H2 and thiosulfate (S2O32–), enabling parallel electron input into the photosynthetic electron transport chain and enhanced growth. Overall, these results establish PPB as robust and metabolically flexible biocatalysts for converting CO2 and industrial waste streams into high-value chemicals with direct applications in the pharmaceutical and nutraceutical industries.