New catalytic synthetic methods in organic chemistry that satisfy increasingly stringent environmental constraints are in great demand by the pharmaceutical and chemical industries. Studies over last 15 years have revealed that activity of enzymes can be increased in organic solvents rather than their natural aqueous environment. Because of their ease of use, high selectivity and environment friendliness, enzymes are enjoying increasing popularity in today's synthesis world. Chapter 1 describes chemo-enzymatic synthesis of various glycolipid analogs. A highly regioselective macrolactonization was achieved using lipase from Candida antarctica as a catalyst. It also describes evaluation of lipases from different source and their efficiency in catalyzing the macrolactonization reaction. These analogs were synthesized using commercially available agriculture based disaccharides (maltose, lactose, cellobiose, melibiose). These glycolipid analogues have potential applications in the cosmetic industry, formulation, food production, and pharmaceutical industry.In Chapter 2, ring opening polymerization of epsilon-caprolactone in ionic liquid, [bmim][PF6] was investigated. A comparative study of ROP in different solvents (toluene, Ionic liquid, and bulk condition) was conducted. Effect of time and enzyme concentration on molecular weight and % yield was investigated. It was concluded that enzymatic ring opening polymerization of epsilon-caprolactone in ionic liquid, [bmim][PF6 ] is a very competitive and environmental friendly way of synthesizing high molecular weight polyesters.

The present study investigated the feasibility of production of sophorolipids (SLs) using yeast Candida bombicola grown on hydrolysates derived lignocellulosic feedstock either with or without supplementing oil as extra carbon source. Several researchers have reported using pure sugars and various oil sources for producing SLs which makes them expensive for scale-up and commercial production. In order to make the production process truly sustainable and renewable, we used feedstocks such as sweet sorghum bagasse, corn fiber and corn stover. Without oil supplementation, the cell densities at the end of day-8 was recorded as 9.2, 9.8 and 10.8 g/L for hydrolysate derived from sorghum bagasse, corn fiber, and corn fiber with the addition of yeast extract (YE) during fermentation, respectively. At the end of fermentation, the SL concentration was 3.6 g/L for bagasse and 1.0 g/L for corn fiber hydrolysate. Among the three major sugars utilized by C. bombicola in the bagasse cultures, glucose was consumed at a rate of 9.1 g/L-day; xylose at 1.8 g/L-day; and arabinose at 0.98 g/L-day. With the addition of soybean oil at 100 g/L, cultures with bagasse hydrolysates, corn fiber hydrolysates and standard medium had a cell content of 7.7 g/L; 7.9 g/L; and 8.9 g/L, respectively after 10 days. The yield of SLs from bagasse hydrolysate was 84.6 g/L and corn fiber hydrolysate was15.6 g/L. In the same order, the residual oil in cultures with these two hydrolysates was 52.3 g/L and 41.0 g/L. For this set of experiment; in the cultures with bagasse hydrolysate; utilization rates for glucose, xylose and arabinose was recorded as 9.5, 1.04 and 0.08 g/L-day respectively. Surprisingly, C. bombicola consumed all monomeric sugars and non-sugar compounds in the hydrolysates and cultures with bagasse hydrolysates had higher yield of SLs than those from a standard medium which contained pure glucose at the same concentration. Based on the SL concentrations and considering all sugars consumed, the yield of SLs was 0.55 g/g carbon (sugars plus oil) for cultures with bagasse hydrolysates. Further, SL production was investigated using sweet sorghum bagasse and corn stover hydrolysates derived from different pretreatment conditions. For the former and latter sugar sources, yellow grease or soybean oil was supplemented at different doses to enhance sophorolipid yield. 14-day batch fermentation on bagasse hydrolysates with 10, 40 and 60 g/L of yellow grease had cell densities of 5.7 g/L, 6.4 g/L and 7.8 g/L, respectively. The study also revealed that the yield of SLs on bagasse hydrolysate decreased from 0.67 to 0.61 and to 0.44 g/g carbon when yellow grease was dosed at 10, 40 and 60 g/L. With aforementioned increasing yellow grease concentration, the residual oil left after 14 days was recorded as 3.2 g/L, 8.5 g/L and 19.9 g/L. For similar experimental conditions, the cell densities observed for corn stover hydrolysate combined with soybean oil at 10, 20 and 40 g/L concentration were 6.1 g/L, 5.9 g/L, and 5.4 g/L respectively. Also, in the same order of oil dose supplemented, the residual oil recovered after 14-day was 8.5 g/L, 8.9 g/L, and 26.9 g/L. Corn stover hydrolysate mixed with the 10, 20 and 40 g/L soybean oil, the SL yield was 0.19, 0.11 and 0.09 g/g carbon. Overall, both hydrolysates supported cell growth and sophorolipid production. The results from this research show that hydrolysates derived from the different lignocellulosic biomass feedstocks can be utilized by C. bombicola to achieve substantial yields of SLs. Based upon the results revealed by several batch-stage experiments, it can be stated that there is great potential for scaling up and industrial scale production of these high value products in future.

This work deals with the current topic of carrier systems. Since the biggest problem is the passage of hydrophobic drugs through the bloodstream, or through universal body barriers (eg blood-brain), it is necessary to chemically modify these carriers in order to be able to administer hydrophobic substances effectively. Based on a literature search, several systems are designed and subsequently studied, in which there is a presumption of possible use for carrier systems and at the same time they have biosurfactants incorporated in them due to their ability to solubilize hydrophobic molecules. The theoretical part of this work will describe the individual biosurfactants, the process of their production, their physicochemical properties, and the possibility of their use in carrier systems. At the same time, the individual carrier systems, the procedure of their preparation, the possibilities of their use are described, and their advantages and disadvantages are also compared. In the practical part, the screening of both individual substances and their mutual interactions, as well as methods used to study the emerging structures is then performed. The study of molecular interactions is primarily performed using the technique of dynamic light scattering. The next part describes the optimization of hydrogel formation with incorporated biosurfactants in their structure and then the formed gels are subjected to rheological and solubilization tests. The study of the internal structure of these gels is performed using a scanning electron microscope.