Photo-driven heterogeneous microbial consortium reducing CO₂ to hydrocarbons fuel

Abstract

Carbon dioxide as feedstock for hydrocarbon synthesis attracts numerous efforts via the biological or chemical approaches. With the purpose of constructing a robust and highly-efficient platform for CO₂ bioconversion to fuel, we investigated a photo-driven bioprocess of directing CO₂ reduction to C₁–C₆ alkanes/alkenes discovered from the enriched microbial consortia. GC-MS analysis revealed that the maximum yield of total gaseous hydrocarbons was 169.66 μM with the average CO₂ reduction rate of 100.87 μM/day decreasing from 11573.39 μM to 5905.73 μM during 50 days culturing. The pathway of CO₂ bioconversion was proposed according to the 16S rRNA and metagenomic sequencing that rTCA and Wood-Ljungdahl were mainly contributed to CO₂ fixation, and nitrogenase was responsible for the hydrocarbon syntheses. Following these results, a versatile consortium-based platform was developed via the neural network method with the selected Pseudomonas sp., Serratia sp., Candidatus sp., Clostridium sp., Enterococcus sp., Salmonella sp., Rhodospirillum sp., Thalassospira sp., Thioclava sp., Stenotrophomonas sp. and Desulfovibrio sp., which showed the improved CO₂ reduction rate of 107.54 μM/day and the higher selectivity of C₁–C₄ alkanes than the original consortia. This study demonstrated that this artificially constructed consortium could be a promising platform for converting CO₂ to the diverse gaseous alkanes and alkenes.

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