Microalgal green refinery concept for biosequestration of carbon-dioxide vis-Ã -vis wastewater remediation and bioenergy production: Recent technological advances in climate research

- This review summarizes critical parameters influencing microalgal CO2 fixation.
- Recent technological approaches to improve CO2 fixation is discussed.
- Integration of flue gas CO2 capture and wastewater treatment for biomass production is highlighted.
- Potential use of biomass to multiple products in biorefinery applications is reviewed.

In recent years, global warming driven climate change is threatening the existence and questioning the survivability of entire humanity. In this context, application of various technologies for Carbon Capture and Storage (CCS) has become essential as sustainable means of reducing CO2 concentration in the atmosphere and also at the point sources of CO2 emission. Among various CCS strategies, biological CCS microalgal cell factories have emerged as important CO2 sequestration platform. This review attempts to capture the global scenario of biological CCS processes vis-à-vis other CCS strategies and endeavors to analyze the role of major physicochemical factors that critically affect CO2 fixation such as microalgal strain, inoculum size, light, temperature, pH, CO2 concentration, mass transfer and flow and mixing. Strategic value additions being made time to time included development of efficient CO2 delivery methods, adoption of smart reactor and metabolic engineering strategies for enhancing photosynthetic rate have also been discussed. Further, this article explores the potential of capturing CO2 from waste flue gas and provides an account of major flue gas components (NOx, SOx, Hg) influencing biomass growth and CO2 fixation efficiency. Finally, the use of wastewater as a nutrient source for the growth of microalgae has been discussed. Our R&D focus and recommendations have thus been on integrating microalgal CO2 capture from flue gas and wastewater remediation for the production of biofuels and value-added products from biomass for the development of a sustainable and green biorefinery model.

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