OPTIMIZATION OF ELASTOLYTIC PEPTIDASE BIOSYNTHESIS BY Bacillus thuringiensis ІМV В-7324

Elastases (E.C. 3.4.21.36, E.C. 3.4.21.37) are enzymes which belong to peptidases that are able to split poorly soluble elastin, the protein which together with collagen provides mammalian connective tissue with mechanic properties. Elastin contains approximately 95% of non-polar amino acid residues and a small amount of polar amino acid residues. The following amino acids have the highest content: Gly (30.7%), Ala (20.4%), Pro (11.4%) and Val (10.5%). The pancreatic elastase splits elastin with the predominant formation of Ala and Val. This enzyme has applied aspects of industrial use for hydrolysis of raw materials with elastin fibers [1]. So, in food industry these peptidases are used for maturation of meat and herring and salting herring. Traditionally, the protein hydrolysates are obtained using peptidases. Then these hydrolysates can be used as food supplements [2] or in leather manufacturing for skin processing at skin dehydratation and softening. It can help to keep the thickness of the final product. Elastases themselves or in the complex with other peptidases can be used for wound treatment for burns, for decrease of inflammatory processes, bruising and swelling etc [3]. Enzymes possessing high thermostability have also a great practical importance and can be used in washing to remove protein contamination [4]. Taking into consideration that elastase purification from animal tissue is accompanied by difficulty the search of elastase producers among microorganisms is an actual problem. Most known producers belong to the genus Pseudomonas, Bacillus, Vibrio, Aeromonas, Aspergillus, Streptomyces and some others. The main drawback of these strains is their pathogenicity for human, so their usage is limited. The isolation of strain-producers which are safe for human health and the increase of enzyme production are the actual problems. As a result of induced mutagenesis by N-methyl-N-nitro-N-nitrosoguanidine the stable variant of the mutant with the increased elastase activity (4 U/mg) was obtained earlier from the strain B. thuringiensis 27 [5]. The EXPERIMENTAL ARTICLES