Biochemical Processes of Oil Degradation

Biochemical Processes of Oil Degradation 1. INTRODUCTION Surfactants are surface active compound that reduce the interfacial tension between two liquids, or that between a liquid and a solid. Surfactants are organic compound that contain both hydrophobic (head part of the surfactant) and hydrophilic (tail part of the surfactant) moieties. Thus surfactant contains both water insoluble i.e. water repellent group as well as water soluble i.e. water loving group. Biosurfactants are also surface active compound like chemical surfactants but unlike the chemical surfactant, biosurfactant are synthesized by microbes like bacteria, fungi and yeast. Biosurfactants comprise the properties of dropping surface tension, stabilizing emulsions, promoting foaming and are usually non-toxic and biodegradable. Recently interest in biosurfactant has increased because of its diversity, flexibility in operation, and more eco-friendly then chemical surfactant (BS Saharan et al ., 2011; Eduardo J. gudiËÅ"na et al ., 2011). Biochemical process es of oil degradation carried out by microbes involves several type of enzymatic reactions driven by oxygenase, dehydrogenase and hydroxylase (Hamamura N et al., 2008). These enzymes cause aliphatic and aromatic hydroxidation, oxidative deamination, hydrolysis and other biochemical transformation of original oil substance leading to formation of large number of intermediate degradation products. However, a major limitation of microbial degradation of crude oil is its hyydrophobicity. Biosurfactant produced by oil degrading bacteria facilitate the uptake of crude oil hydrocarbons by bacterial cells and also have low toxicity and high biodegradability (Batista SB et al. , 2006). So, crude oil degrading bacteria with the ability to produce biosurfactant is widely recommended for fast degradation of crude oil. (Kumar M et al., 2006). Furthermore possibility of their production on large scale, selectivity, performance under intense conditions and their future applications in environ mental fortification also these have been increasingly attracting the attention of the scientific and industrial community. These molecules have a potential to be used in a variety of industries like cosmetics, pharmaceuticals, humectants, food preservative and detergents (BS Saharan et al. , 2011). But the production of biosurfactant on industry level is still challenge because of using high costly synthetic media for microbial growth. Biosurfactants are classified on the basis of diversity in their structure and their microbial origin. They contain a hydrophilic group, that contain an acid, peptide cations, or anions, mono-, di- or polysaccharides and a hydrophobic group of unsaturated or saturated hydrocarbon chains or fatty acids. Biosurfactants produced by a variety of microorganisms mainly bacteria, fungi and yeasts are diverse in chemical composition and their nature and the amount depend on the type of microbes producing a particular biosurfactant. 1.1 Classification of Bio surfactant: Biosurfactants are classified in to two major group one is low molecular weight surface active agent call biosurfactant and high molecular weight substance called bio-emulsifier that is especially used as enhancement of emulsification of hydrocarbon. Further these two major group is divided in to six major group known as glycolipids, lipopolysaccharides, lipoproteins-lipopeptides, phospholipids, hydroxylated and cross linked fatty acids. (a) Glycolipids: Mostly biosurfactants are glycolipds. They are lipids with a carbohydrate attached. The connection is by means of either an ether or ester group. Among the glycolipids, the best known are rhamnolipids sophorolipids and trehalolipids.