Biodiesel Fuel Production from Algae as Renewable Energy
- TCSC Botany
- Jul 8, 2022
- 3 min read
Energy resources like Fossil fuel are depleting rapidly and most importantly the liquid fossil fuel will be diminished by the middle of this century. An alternative to fossil fuels can be provided by Algae biofuels. New research claims that ‘vast’ quantities of renewable fuels can be produced from algae using innovative gene editing technique.
Algal species grow in a wide range of aquatic environments, from freshwater through saturated saline. Algae can produce biomass very rapidly, with some species doubling in as few as 6 h, and many exhibiting two doublings per day. For example, some Botryococcus spp. have been identified that have up to 50% of their dry mass stored as long-chain hydrocarbons
Short harvesting cycle of algae is the key advantage for its importance, which is better than other conventional crops having harvesting cycle of once or twice in a year
The biofuel synthesis from algal biomass proceeds through the following steps.
Culturing of algae, Harvesting of algae, Extraction of oil from algae, Purification of algal oil and Processing of oil into biofuels.
1. Culturing of algae - Similar to that of aquaculture Algaculture refers to the growth of algae. The growth expectation of algae is very simple and affordable i.e. sufficient light, naturally available dissolved nutrients and CO2.
Three major types of culturing are:
Open pond system, Photo bioreactors-Closed loop culturing & Hybrid systems
2. Harvesting or de-watering or algae
In order to access the lipid profile the cultured algae needs to be dewatered the experiments prove that only 0.1% of dry matter is available in 1 L of cultured media. Filtration and centrifugation are the processes involved in removing water from algae. Flocculation and membrane filtration is effective in drying algae Methods involved in filtration: Pressure, Vacuum, deep bed sand, cross flow and magnetic filtration.
3. Extraction of Oil from Algal Biomass
Unicellular microalgae produce a cell wall containing lipids and fatty acids, which differ them from higher animals and plants. In the literature, as mechanical and solvent extraction methods of oil extraction from algae are used.
Biofuel synthesis from algae by transesterification process
This is a process to convert algal oil to biodiesel. Catalysts plays a vital role in the biodiesel forming reaction irrespective of the type of oil examined. But, Remarkable tendency to get converted into diesel range esters is displayed by algal oil. Catalyst Hβ and mixed oxide of Nickel and Molybdenum turns to be veracious materials. The reaction can be performed in the presence of an inorganic catalyst or lipase enzyme. About 3 mol of alcohol are required for each mole of triglyceride to produce 3 mol of methyl esters (biodiesel) and 1 mol of glycerol (by-product). Biodiesel is recovered by repeated washing with water to remove glycerol and methanol.
Alkali-catalysed transesterification reaction has been reported to be 4000 times faster than the acid-catalysed reaction
Mostly aquatic unicellular green algae (Chlorophyceae) are used for the production.
1.Chlorella
Is a single-celled green algae belonging to the class of Chlorophyceae.
It grows autotrophically so it’s a primary algae.
About 2 to 10 μm in diameter, It is spherical in shape and does not have a flagella
2.Dunaliella
It’s a unicellular primary green algae. It is rod to oval shaped and about 9 to 11 μm in diameter.
The technique could be used in future to improve disease resistance, increase crop yields or enable plants to survive in harsher climates.
References:
Name : Aman kumar
Roll no : 1518
Class : S.Y.B.sc(CB)
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