Algae as Alternative Fuel Sources: Present and Future Challenges-A Review

Global warming is primarily caused by carbon dioxide (CO2) emission. The global temperature late last century was 0.48 degrees Celsius higher than that 100 years ago; the CO₂ in the atmosphere has increased by 25% since the industrial revolution and is still on the rise. The recently concluded Paris Climate Conference agreed to limit the temperature rise by 2020.

Combustion of coal, oil, natural gas, familiar to us in our daily life, all contribute to a large amount of CO₂ emission into the atmosphere, resulting in adverse effects on the climate, The natural carbon cycle is upset due to the continuous usage of fossil fuels. To mitigate the situation, people all around the world are trying the carbon capture storage methods/development of benign alternative fuel sources.

Algae are simple unicellular organisms that produce carbohydrates, proteins and lipids as a result of photosynthesis. Microalgae have the ability to fix CO₂ using solar energy with efficiency of 10 times greater than that of terrestrial plants, and also have higher growth rates, allowing a large quantity of biomass to be produced in a shorter amount of time and smaller area. Though there are many advantages over other microorganisms for mass production, algae face their own limitations in mass cultivation, lipid induction, harvesting, extraction of algal oil and conversion of oil to biofuel, which at industrial scale have no viable solutions yet. Many research institutes/industries are trying to solve these very basic problems.

This review gives an overall scenario to understand where the research on algal biofuels is heading towards.