Algae as Biofuel

Algae are a group of plants, mostly adapted to aquatic habitats. The cellular construction of algae may be simple unicellular to large multicellular eukaryotes. The classification of algae is controversial; they are classified under plants as they are autotrophic and can synthesize their own food by photosynthesis. Whereas in some studies, algae are not considered as plants as the former lacks certain complex structures of plants like true leaves, rhizoids and roots.

Algae play a major role in the functioning of ecosystem or food chain. They serve as food for small fish and other organisms living in aquatic conditions. Algae are used in various ways; they are used as a source of food for animals and humans since ancient times. The highly proteinaceous supplement spirulina is prepared from algae, and is used for treatment of malnutrition among children. In present day scenario, the issue of oil crisis has led to the discovery of using algae for the production of biofuel.

Algae as Biofuel

Biofuel refers to fuel, produced from living or recently dead organisms. It can be in the form of solid, liquid or gaseous states. Biofuel is used for running vehicles, supplying electricity for household appliances and for cooking. Due to presence of large biomass of algae in freshwater and marine sources, extensive studies have been conducted for the use algae as a potential source of biofuel. For production of biofuel, mass cultivation of algae or algaculture is carried out in various regions of the world. The important fuels synthesized from algae are vegetable oil, biogas, biodiesel, biomethanol, bioethanol, biobutanol and dry fuel (similar to coal). Many countries have implemented highly sophisticated techniques for enhancing mass-scale cultivation of algae.

Advantages and Disadvantages of Algae as Biofuel

The rapid growth of algae is a contributing factor for mass cultivation without spending extra resources. Some species of algae can double their mass within a day. In comparison to traditional fossil fuels and other biofuel sources such as soybeans or jatropha, there are certain advantages of using algae, which are highlighted as follows:

• One of the major benefits of algae as biofuel is that many algal species, particularly the small species can be used for extraction of biofuel.
• The yield of vegetable oil from algae is comparatively much higher (about 30 times) than land crops.
• Marine water as well as wastewater can be used for mass cultivation of algae.
• Unlike fossil fuels, biofuel produced from algae are biodegradable, thus reducing the chances of environmental pollution.
• In case there is spillage of algal-based biofuel in water sources, there are no significant adverse effects on the ecosystem.
• Algal-based biofuel does not affect the natural freshwater sources.

As per studies conducted on algae, it is observed that about 60 percent of their biomass can be converted into biofuel. The microalgae species are economically beneficial for biofuel production than other larger algae species. The amount of carbon emission after using algal biofuel is lower than those of fossil fuels.

In spite of the many benefits of algae as biofuel, there are some drawbacks. The performance of algal-based biodiesel is lower than other alternatives like biodiesel extracted from rapeseed and soybean. The production of biodiesel from algae also results in several other unstable compounds. Since biofuel production from algae is a relatively new technology, more researches are required to be conducted to develop standardized protocols for cultivation and biofuel production.