Microbial Production and Characterization of 3, 4-dihydroxy-L Phenylalanine Mediated an Extracellular Heterogenic Eumelanin Pigment From Marine Actinomycetes Prauserella Sp. MAPPL 017A

Melanin is one of the natural biological pigment and it is derived from the enzyme tyrosinase by the oxidation of an amino acid tyrosine. The enzyme tyrosinase [EC 1.14.18.1] is a type-3 copper protein family found large amount in microorganisms and human beings involved in the biosynthesis of melanin and other polyphenolic compounds. Melanin plays an important role in all living creatures such as photo protectants against UV radiation, antioxidant, metal adsorption, electrical conductivity, camouflage, anti-aging properties, virulence and fungal pathogenesis. The above properties of melanin can be used in various application purposes which make the melanin expensive and great demand in the industry. To overcome the above situation, there is a necessity to find out the new biological sources for the maximum production of melanin. Numerous reports are available on fungal and bacterial melanin but only a few of them from actinomycetes. Based on the above view, the present investigation was aimed to purify the DOPA melanin from the novel marine actinomycetes Prauserella sp. (MAPPL 017A). Purified melanin was characterized using several state-of-the-art techniques and it’s showed the broadband absorbance, presence of carboxylic and indolic groups, high amount of carbon, nitrogen and low level of sulfur, presence of other metal ions such as calcium, sodium and magnesium with efficient thermal properties.

Influence of bacterial melanine on morphological indicators of seeds germination of high-decorative species of flora of Belarus

Aim. The purpose of the work is to study the effect of a biological product based on the melaninogenic strain of Bacillus thuringiensis on germination and morphological parameters of highly decorative species of the flora of Belarus, promising for landscaping in the urban environment. Methods. Seed germination in laboratory conditions used with soaking in solutions of bacterial melanin in concentrations of 0.04, 0.025, 0.01%. Water and Terrasil at a concentration of 0.01 was used for a comparative evaluation of the effectiveness. Results. Morphological parameters were estimated during germination of the seeds of Verbascum thapsus L., Verbascum nigrum L., Centaurea scabiosa L., Betonica officinalis L., Viscaria vulgaris Bernh. treated with various concentrations of the stimulant. Conclusions. The effect of the bacterial melanin on the morphological parameters of plants was species- and dospecific. The optimal concentration for use on the studied plants should include concentrations up to 0.025%. The most pronounced effect of the use of the drug was revealed in the first days of seed germination, which allows the use of bacterial melanin to increase the germination of seedlings. Keywords: bacterial melanin, stimulant, seed germination, highly decorative species of flora.