Utilization of Crude Glycerol from Biodiesel Industry for the Production of Value-Added Bioproducts

The rapid economic development and industrialization mainly depends on fossil fuels for their energy sources. Diminishing oil reserves, high cost and other environmental problems lead the researchers to ripen carbon-unbiased and sustainable alternative to fossil fuels. When compared with other alternate fuels, biodiesel gained its popularity. The dynamic growth of biodiesel production results in colossal generation of glycerol as a waste by-product of about 10% of the total biodiesel production. Disposal of crude glycerol tainted with salt, methanol, free fatty acids, etc., causes severe economic and environmental challenge. However, high cost of crude glycerol purification and market saturation urges the biodiesel producers to look for new, cheaper, and alternate solution for utilizing it. Presence of impurities and its composition in crude glycerol can have a negative influence in the fermentation process by inhibiting microbial growth and product formation. Microbial fermentation of crude glycerol represents a notable alternate and competitive to add value for the biodiesel producers. Hence, pre-treatment of crude glycerol becomes requisite before using it as carbon source. The higher degree reduction of carbon atom in glycerol confers that it could be used as a sole organic carbon and energy source for the production of higher value chemicals such as citric acid, ethanol, DHA, glyceric acid.