MOLECULAR DESIGN AND SYNTHESIS OF ANTIMICROBIAL PEPTIDES OF WIDE RANGE

Lactic acid bacteria form a wide range of bacteriocins, the compounds that inhibit ineligible food product microflora. New producers are vigourously searched and bacteriocin properties are actively studied. Creation of new antimicrobial peptides consisting of C- and N-parts of various bacteriocins is of great concern. Based on co-use of nisin, lactocin and enterocin, their antimicrobial effect is proved to increase with the well matching combination of bacteriocins of different origin. Either, development of genetically altered strains of fungi and bacteria is promising that are capable of producing one or more enterococcus bacteriocins and other LAB. This work describes procedures to integrate structures producing Lactobacillus paracasei and Pediococcus acidilactici strain bacteriocins isolated from fermented milk products used by people residing in the south of the Western Siberia into E. coli BL21DE3 competent cells using the commercial vector Mud5005-13. The strains obtained were analyzed for successful integration by induction of pathogenic bacteria by lysates and it was shown that, irrespective of the induction time, the recombinant strain effectively synthesizes the bacteriocin construct integrated. Best conditions were developed for the strain culturing to achieve the highest yield of the recombinant peptide into the culture medium comprising of: medium № 6 containing the following per 1 liter: tripton - 12 g, sucrose - 12 g, sodium acetate 0.5 g, magnesium sulfate - 0.2 g, ammonium sulfate - 0.5 g, sodium chloride - 6 g, calcium chloride - 2 g; culturing temperature - 40°C; agitation speed - 200 rpm; aeration value is 1 l/l*min.