Review on enzymatic synthesis of value added products of glycerol, a by-product derived from biodiesel production

Crude glycerol is produced as a by-product from biodiesel production via trans-esterification with methanol and this process accounts for 10% (w/w) of the total biodiesel produced worldwide. The glycerol glut created can be utilized to increase biodiesel profitability since disposal can pose a threat to the environment. The need is to transform this surplus crude glycerol into added-value products. Biological based conversions are efficient in providing products that are drop-in replacements for petro-chemicals and offer functionality advantage, commanding higher price with the potential to increase bio-refinery revenue. Glycerol is a stable and multifunctional compound used as a building block in fine chemical synthesis like bio-polymers, polyunsaturated fatty acids, ethanol, hydrogen, n-butanol, glycerol carbonate, glycerol acetyl esters etc. Bio-catalysts add higher value to bio based products by catalyzing not only their selective modification, but also their synthesis under controlled and mild conditions. This article focuses on different bioconversion technologies of crude-glycerol to value added industrial products - obtained as waste from current bio-diesel production. We abridge the recent relevant approach for the production of various platform chemicals from bio-glycerol over enzyme and chemical catalysts.