Autotrophic and mixotrophic culture of electro-active microalgae with electron supplied from electrodes for CO2 conversion

Abstract

Electrochemical technologies that involve microorganisms are considered to be promising for sustainable applications. Microalgae can be used for carbon capture through photosynthesis which can directly fix carbon dioxide (CO2). The conversion of CO2 into fuel energy and other high value metabolites without pollution can contribute to reduce CO2 emissions with more economic value. Light energy to biomass conversion efficiency is a major challenge in microalgal cultivation. Electrode assisted cultivation techniques for improved photosynthetic and carbon (CO2) fixation metabolism for growth and biomass productivity have rarely been explored for microalgae. Light limitation, which leads to the loss of photosynthetic efficiency that in turn leads to decreased microalgal growth, is a major problem in large scale cultivation systems. Here, we summarise the ability of microalgae to perform extracellular electron uptake from cathode material for efficient biomass production and CO2 conversion. The present review provides insights into the possible development of electroactive microalgae under autotrophic and mixotrophic conditions for efficient CO2 conversion. Using the current knowledge of bioelectrochemistry and learning lessons from electroactive bacteria, we propose a proof of concept for electroactive microalgae and their future applications in CO2 sequestration.