Microalgae

Effect of different concentrations of nitrogen (N) source (NaNO3) of BG-11 medium on growth of freshwater microalgae Chlorella vulgaris is studied. Different nitrogen step down concentrations of NaNO3 in per litre of medium were used like 17.6 mM (control), 8.8 mM and 4.4 mM. Optimum lipid was obtained with treatment of 8.8 mM NaNO3 concentration that showed 29.30 µg lipid per 100 µg of biomass. However, biomass in term of protein was higher (602.64±0.97 µg/ml) at 17.6 mM of NaNO3 concentration. Treatment of 4.4 mM NaNO3 concentration resulted in 20.03 µg of lipid per 100 µg biomass, which was higher than control, but with poor yield of biomass. Result indicates that changing the N concentration in BG-11 medium result in enhanced lipid production in Chlorella vulgaris.

Energy security and conservation of environment are two key factors, indispensable for the growth, progress and sustainability of the human race. The fossil fuels reserves are depleting at an alarming rate; however, their major role in green house gases emissions is becoming even more dangerous for the environmental and ecological balance. Driven by these facts, world over, the researchers are determined to find alternative renewable and potentially carbon neutral biofuels as alternative energy sources. The alternate energy sources like the first generation biofuels derived from food crops such as maize, sugarcane, rapeseed and sugar beet caused a great worry to world food markets and exaggerated the water shortages. Second generation biofuels obtained from lignocellulosic residues of agriculture and nonfood crops address some of the issues; but, there is concern over land use changes. As a consequence, third generation biofuels specifically derived from microalgae are considered to be commercially viable alternative energy sources, free from major disadvantages associated with first and second generation biofuels. Like plants microalgae are photosynthetic in nature, known to produce carbohydrates, proteins and lipids in large quantities in short durations of time. This review focuses on various technologies used for the production of biofuels from algae. The outcome of the study reveals that the microalgae-derived biofuels could gradually replace the petroleum diesel to meet the growing energy needs.