Abstract
Energy makes the world go round. According to the statistical energy report by some oil companies fossil fuels meet approximately 88% of the worlds energy need. The need for energy and thus fossil fuel is going to increase with increase in world population. With the estimated increase in population it is unsustainable to depend on the fossil fuel for further energy demand, owing to depleting world fuel reserves and GHG emission. This
review paper focuses mainly on the alternative for fossil fuels, the Biofuels. Biofuels can offer several opportunities to increase income sources, provide sources for supplying fuel, to increase the employment opportunities in villages, to reduce GHG emissions into atmosphere and increasing the security of energy supply. This paper spots light on the
biofuels currently under development and will be a major contributor towards fuelling the future. The first generation biofuels obtained from plants like corn, sugarcane, sugar beet etc. faces challenges like high land and water demand, low productivity, disturbing biodiversity and puts strain on the world market as these are consumed by people. So we have second generation biofuels derived from
lignocellulosic forest and agricultural residue, non-food crop feedstock but they also have less productivity and require more land.
Therefore from the present knowledge and technology available the third generation biofuel especially from micro algae are of great importance. They can be easily cultivated, can live in harsh conditions, requires less water, can grow in waste water, their productivity is significantly higher, helps in sequestering carbon from environment
etc. Micro-algae are photosynthetic microorganisms and require light, sugars, CO2, N, P, and K for living that can produce lipids, proteins and carbohydrates in large
amounts in less time and then can be processed to give biofuels and various valuable products. The selection of microalgae strain, the various methods of cultivating like Open pond or Closed system like photo bioreactor and techniques for harvesting of micro-algae like flocculation, centrifugation, biomass filtration, ultrasonic aggregation, sedimentation etc. were studied. The extraction and purification of lipids were also studied. As a part of review, various algal biofuel conversion techniques which can be classified as thermal conversion and biochemical conversion were studied. Some of the synergistic approaches like combining
biofuel production with waste water treatment and carbon sequestering were observed. The concept of photosynthetic efficiency (PE) is also studied from which it is found micro-algae have comparatively high PE and also
high potential to increase PE and productivity making it most efficient biomass resource for biofuel production. Hence the further study should be carried out on increasing efficiency, scaling the process including integration of various technologies like wind, solar, tidal etc.
Keywords: Bioenergy, Biofuels, CO2 Sequestration, Mcroalgae, Sustainability, Third Generation Biofuels
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