Feasibility and viability of procuring biohydrogen from microalgae: An emerging and sustainable energy resource technology

Abstract

As the world's population is increasing at an unprecedented rate, causing a severe impact on the limited and depleting petroleum reserves by their overexploitation and consumption. It is estimated that due to increasing socioeconomic and infrastructural advancements, we have already consumed about 50% of the petroleum reserves. Furthermore, the excessive usage of fossil fuels is believed to be a potential cause of global warming and a threat to environmental sustainability. This led the researchers to explore and study renewable and carbon-neutral sources of energy, which can be optimized as per the requirement and should be economically viable. Microalgae stand out momentous and materialized as feedstock to get all that we need at a single platform. Microalgae are the primary producers that utilize Carbone dioxide CO2 and light for their growth. They can be grown in freshwater, saline water, and even in wastewaters due to their disparate biochemical metabolism. This urged microalgae to be exploited for obtaining various renewable energy-based fuels, as it has the following significant features: potential for CO2 fixation; high biomass growth rate; its capacity to store carbon in lipids and carbohydrates to produce biofuels (bioethanol, biodiesel, biohydrogen, and biomethane). Recently, Hydrogen have gained interest as one of the most environmental friendly fuel. Hydrogen has numerous merits as compared with others fuel. The range of energy content is 120-142 MJ/Kg and it has high content (142 MJ/kg) as comparing with energy content of gasoline (47 MJ/kg), methane (56 MJ/kg), and natural gas (54 MJ/kg) while, the energy density is 8.5-10.1MJ/L. Furthermore, the yield is 92-485 mL/gVS and cetane number 50-53. This mini review provides an insight about the processes of biophotolysis, and fermentation utilized in the production of biohydrogen utilizing microalgae. It will incorporate the recent developments and innovations in biohydrogen production using microalgae. It will also give an overview of the challenges encountered in the production routes and the future perspectives.