Recent Advances in Carbon Dioxide Conversion: A Circular Bioeconomy Perspective

Abstract

Managing the concentration of atmospheric CO2 requires a multifaceted engineering strategy, which remains a highly challenging task. Reducing atmospheric CO2 (CO2R) by converting it to value-added chemicals in a carbon neutral footprint manner must be the ultimate goal. The latest progress in CO2R through either abiotic (artificial catalysts) or biotic (natural enzymes) processes is reviewed herein. Abiotic CO2R can be conducted in the aqueous phase that usually leads to the formation of a mixture of CO, formic acid, and hydrogen. By contrast, a wide spectrum of hydrocarbon species is often observed by abiotic CO2R in the gaseous phase. On the other hand, biotic CO2R is often conducted in the aqueous phase and a wide spectrum of value-added chemicals are obtained. Key to the success of the abiotic process is understanding the surface chemistry of catalysts, which significantly governs the reactivity and selectivity of CO2R. However, in biotic CO2R, operation conditions and reactor design are crucial to reaching a neutral carbon footprint. Future research needs to look toward neutral or even negative carbon footprint CO2R processes. Having a deep insight into the scientific and technological aspect of both abiotic and biotic CO2R would advance in designing efficient catalysts and microalgae farming systems. Integrating the abiotic and biotic CO2R such as microbial fuel cells further diversifies the spectrum of CO2R.

Arthrospira platensis Cultivation in a Bench-Scale Helical Tubular Photobioreactor

“…Microalgal cultivation technology has gained widespread attention because microalgae combine the renewable energy-capturing ability of photosynthesis with the high production rates of controlled microbial cultivation, which makes them potentially valuable organisms for cheap industrial production processes [5,7]. They represent the main natural source of useful and valuable molecules with numerous practical applications, for the majority of which the market is still developing; furthermore, the biotechnological use of microalgae is likely to extend to new areas.…”

“…It is mainly due to the emission into the atmosphere of greenhouse gases, such as CO 2 produced by the combustion of fossil fuels [5]. An attractive alternative to reduce carbon dioxide emissions could be the use of photosynthetic microorganisms able to utilize this pollutant as a carbon source for their growth [5,7]. From this point of view, the photoautotrophic cultivation of the cyanobacterium A. platensis would allow to produce valuable biomass using the CO 2 from industrial processes and other human activities as a carbon source [38].…”