Mechanisms of strengthening energy and mass transfer in microbial conversion of flue-gas-derived CO2 to biodiesel and biogas fuels

Abstract

The goals of national energy security and sustainable development necessitate the role of renewable energy, of which biomass energy is an essential choice for realizing the strategic energy diversification and building a low-carbon energy system. Microbial conversion of flue-gas-derived CO2 for producing biodiesel and biogas has been considered a significant technology in new energy development. Microalgae carbon sequestration is a hot research direction for researchers. However, three fundamental problems relating to energy/mass transfer and conversion remain as follows: (1) contradictory relationship between high resistance of cell membrane micropores and high flux of flue-gas-derived CO2 limits mass transfer rate of CO2 molecules across cell membrane; (2) low biocatalytic activity of intracellular enzymes with high-concentration CO2 results in difficulties in directional carbon/hydrogen conversion; (3) competition between multiple intracellular reaction pathways and high energy barriers of target products hinder the desirable cascade energy transfer. Therefore, key scientific issues of microbial energy conversion lie in the understanding on directional carbon/hydrogen conversion and desirable cascade energy transfer. Multiple researches have established a theoretical foundation of microbial energy conversion which strengthens energy/mass transfer in microbial cells. The innovative results in previous studies have been obtained as follows: (1) Reveal mass transfer mechanism of vortex flow across cell membrane micropores. (2) Propose a strategy that directionally regulates enzyme activity. (3) Establish chain reaction pathways coupled with step changes.