الفهرس 
acknowledgmentOnly 14 pages are availabe for public view
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Abstract
Lipids constitute alarge part of the earth,s biomass and lipolytic enzymes play an important role in the turnover of these water-insoluble compounds. Lipases are involved in this breakdown process and thus in the mobilization of lipids within the cells of individual organisms as in the transfer of lipids from one organism to another. Lipolytic enzymes share a unique physico-chemical character of the reaction they catalyze at lipid-water interfaces this involving interfacial adsorption and subsequent catalysis (1) Lipases areubiquitous enzymes, which are found in animals, plants, fungi and bacteria.(2-11)
In industrially developed countries, the edible lipids present in the human diet, which consist mainly of triacylglycerols (TAGs), ranges from 100 to 150 grams per day i.e. 30% of each individual,s daily caloric intake. These TAGs molecules cannot cross the intestinal barrier and thus a series of hydrolytic and adsorption rections are therefore necessary to produce the chemical energy resources present in the hydrocarbon chains of biologically usable TAGs. The lipolytic enzymes in the digestive tract therefore play an important role in nutrition processes both in humans and higher animals.
Lipolytic enzymes specially lipases are the most versatile biocatalyst and bring about numerous bioconversion reactions such as hydrolysis, interesterification. Esterification, alcoholysis, acidolysis, enantioselective reactios and aminolysis. The panorama of lipases in the manufacture of fine chemicals is depicted with special emphasis on pharmaceuticals, pesticides, cosmetics, biosensors and detergents. Moreover, novel aspects of lipases utilization include waste management and improved tanning techniques. (12) Although lipases are widly distributed, those from microorganisms are most interesting because of their potential application in various industries.
In the past the high cost of these enzymes was the reason for low interest especially for the potential larger applications such as in the detergent industry. However, with the advent of recombinant DNA and molecular biology, the production technology of lipases has made great progress in the last five years. As a consequence of this development, many different lipasdes from many different microorganisms are now available especially for the detergent industry which did the great benefit from this progress and is by now the largest application area of industrial lipases. (13,14) The present study focuses on screening some microbial isolates for such industrially important enzyme, production, isolation and characterization of this enzyme.