Prospects of Bioethanol from Estuarine Macroalgae

Abstract

Burgeoning dependence on fossil fuels for transport and industrial sectors has been posing challenges such as depletion of fossil fuel reserves, enhanced greenhouse gas (GHG) footprint, and imminent changes in the climate, etc. Fossil fuels are regarded as unsustainable and questionable from economic, ecology and environmental point of view. Therefore, the pursuit for an environmentally benign and sustainable source of energy started with the advent of oil crisis in 1970, major focus of energy policies shifted to biofuel production from renewable resources. Biofuels minimizes the fossil fuel burning and CO2 production, as it is produced from biomass such as plants or organic waste, thereby decreasing the dependence on oil. The review on evolution of biofuel production from first to second-generation feedstock revealed that the process requires higher concentration of chemical usage due to the presence of lignin. In addition, this feedstock requires arable land and freshwater source for their large-scale cultivation. Recent studies on biofuels indicate that algal biomass; particularly from marine macroalgae (or seaweeds) have the potential to supplement oil fuel Macroalgae with higher concentration of varied carbohydrates (constituting as a source of energy) are emerging as a potential and renewable feedstock towards sustainable biofuel production due to their higher growth rate and availability. Macroalgal biomass cultivation with biorefinery approaches not only aid in empowering rural women with the better economic prospects, but also aid in addressing strategic energy security of the nation. Ceasing of cultivation of salt tolerant paddy and recurring losses with the prawn cultivation (due to viral diseases); have forced abandoning of gazni lands, which can now be used for large-scale cultivation of macroalgae. Macroalgae biomass with higher composition of carbohydrates is relatively higher in gazni, ponds compared to natural rocky shores. In addition, harvesting of algal feedstock in gazni ponds is economical compared to sparsely distributed macroalgae in rocky stretches of the region. Biorefinery approach of macroalgae and macroalgal cultivation for this purpose in Aghanashini estuary could be a good income-generating proposition for the fishermen as well as aid in empowering coastal women