Abstract: The use of liquid fossil fuel has long being considered insufficieunt and surely the liquid fossil fuel will be diminished by the middle of this century. Besides fossil fuel is closely related to environmental degradation and green house emission. On the other hand biofuel has been a great renewable alternative for this situation produced from plants, plants products, animals and microalgae. Among these, microalgae are the outstanding sources of biofuel containing huge amount of lipid which reduce the demand of fossil fuel and help in environmental stability.
Inroduction: With the passage of time, increased population and industries are to use fossil fuel. Without it normal life can not be imagined though it has an obnoxious effect on environment. So policy makers, scientist, researchers and governments has been looking alternative renewable energy sources. Biofuel is their desired substance which can abate oil price rate, climate changes and related problems.
- Microalgae are currently being promoted as an ideal third generation biofuel feedstock because of their rapid growth rate, greenhouse gas fixation ability (net zero emission balance) and high production capacity of lipids (fat).
- They also do not compete with food or feed crops, and can be grown on non-arable land and saline water. Biofuels are generally referred to solid, liquid or gaseous fuels derived from organic matter.
There are three kinds of biofuels according to generation :
- 1st Generation Biofuels
Bioethanol produced from
– Wheat, barley, corn
– Potato, sugarcane, beet
– Oil seeds (soybeans, coconut, sunflower, rapeseed, animal fat, used cooking oil)
- 2nd Generation Biofuels
Bioethanol & Biodiesel produced from
– Cassava, Jatropha, Miscanthus
– Straw, grass, wood
- 3rd Generation Biofuels
Biodiesel produced from
The first generation biofuels possess notable economic, environmental and political concern as the mass production of biofuel requires more arable agricultural lands resulting in reduced lands for human and animal food production. Moreover, production process of first generation biofuels is also responsible for environmental degradation. Therefore, enthusiasms about first generation biofuels have been demised. As first generation biofuels are not viable, researchers focused on second generation biofuels. Because of the second generation biofuels production process requires expensive and sophisticated technologies, the biofuel production from the second generation is not profitable for commercial production .
Therefore, the researchers focused on third generation biofuels. The main component of third generation biofuels is microalgae. It is currently considered to be a feasible alternative renewable energy resource for biofuel production overcoming the disadvantages of first and second generation biofuels. Microalgae can provide several different types of renewable biofuels. This includes methane, biodiesel and bio-hydrogen. There are many advantages for
producing biofuel from algae as microalgae can produce 15 to 300 times more biodiesel than traditional crop on area basis. The harvesting cycle of microalgae is very short and growth rate is very high . Moreover, high quality agricultural land is not required for microalgae biomass production.
Biofuel Production from Microalgae:
Microalgae are single-cell microscopic organisms which are naturally found in fresh water and marine environment. There are more than 300,000 species of micro algae, diversity of which is much greater than plants. Microalgae are generally more efficient converters of solar energy comparing to higher plants. In addition, because the cells grow in aqueous suspension, they have more efficient access to water, CO2, and other nutrients.
Microalgal Biomass Production:
Producing microalgal biomass is generally more expensive and technologically challenging than growing crops. Photosynthetic growth of microalgae requires light, CO2, water and inorganic salts. The temperature regime needs to be controlled strictly. For most microalgae growth, the temperature generally remains within 20°C to 30°C. In order to reduce the cost, the biofuel production must rely on freely available sunlight, despite daily and seasonal variations in natural light intensities. Growth medium must provide the inorganic elements that constitute the algal cell. Essential elements include nitrogen (N), phosphorus (P), iron (Fe) and in some cases silicon (Si). Microalgae is grown in various aquatic environments, such as fresh and marine water, municipal waste waters, industrial waste waters and animal waste water.
In Banglades:Bangladesh has plenty of fresh water and marine habitats for algal growth.So our government and researchers should concentrate in producing biofuel from algae. If it is possible, our economy will rise, environment will be greener.
Conclusion: Though biofuel has been playing significant role in the field of economy and environment, it is still manipulated by private authority. Government should invest in this field as early as possible.