Abstract
Melanins have immense application potential in the fields of agriculture, cosmetics and pharmaceutical industries. To determine the antimicrobial properties of melanin, conditionally pathogenic bacteria, belonging to different taxonomic groups were used. The results have shown that melanin solution exhibited bacteriostatic or bactericide activity depending on test culture and melanin concentration. Melanin at concentration of 20 mg/ml reduced the total number of cells of the Bacillus subtilis G 17-89, Salmonella typhimurium G 38 and Escherichia coli K 12 to about 20 percent. Melanin at the concentration of 40 mg/ml suppressed the growth of B. subtilis G17-89 and Candida gropengiesseri 10228 almost 100 percent. In the case of E. coli K 12 30 mg/ml concentration has the same effect as the 40 mg/ml and cell count decrease occurs about 50 percent. Lowest efficiency melanin showed against S. typhimurium G 38 and after 72 h of incubation the cell count decreases by log 1 degree. 30 mg/ml concentration of melanin on the growth of Candida bovina 10118 decreases about 80 percent. On the growth of the Fungi of Aspergillus fumigatus 8444, Aspergillus flavus 10559, Cladosporium herbarium 8270, Cladosporium elatum 8192, Fusarium oxysporum 12017, Fusarium solani 12018, Mucor hiemalis 12020, Mucor plumbeus 12021, Penicillium chrysogenum 8203, Penicillium expansum 8281 genus low concentration of melanin possessed bacteriostatic activity. The investigation of the efficiency of melanin to inhibit the growth of food-spoilage microorganisms shown, that it can be used as natural preservative agent for prevention contamination of food products and for extending of their shelf-life.