Microalgae to bioenergy production: Recent advances, influencing parameters, utilization of wastewater – A critical review

Fossil fuel limitations and their influence on climate change through atmospheric greenhouse gas emissions have made the excessive use of fossil fuels widely recognized as unsustainable. The high lipid content, carbon-neutral nature and potential as a biofuel source have made microalgae a subject of global study. Microalgae are a promising supply of biomass for third-generation biofuels production since they are renewable. They have the potential to produce significant amounts of biofuel and are considered a sustainable alternative to non-renewable energy sources. Microalgae are currently incapable to synthesize algal biofuel on an extensive basis in a sustainable manner, despite their significance in the global production of biofuels. Wastewater contains nutrients (both organic and inorganic) which is essential for the development of microalgae. Microalgae and wastewater can be combined to remediate waste effectively. Wastewater of various kinds such as industrial, agricultural, domestic, and municipal can be used as a substrate for microalgal growth. This process helps reduce carbon dioxide emissions and makes the production of biofuels more cost-effective. This critical review provides a detailed analysis of the utilization of wastewater as a growth medium for microalgal – biofuel production. The review also highlights potential future strategies to improve the commercial production of biofuels from microalgae. [Display omitted] •Microalgae are photosynthetic microorganisms having abundance reservoir of carbohydrates, proteins and lipids.•Integrated microalgae cultivation with wastewater treatment is a sustainable and promising approach for biofuel generation.•Biohydrogen, biodiesel, bioelectricity, biogas, bioethanol are produced from microalgae via. different techniques.•Two-stage hybrid microalgae cultivation systems offer enhanced biomass and thus, better resource recovery.•Zero-waste idea concept is a solution for huge wastewater generation due to urbanization.