Production and Cytotoxicity of Extracellular Insoluble and Droplets of Soluble Melanin byStreptomyces lusitanusDMZ-3

Abstract

A Streptomyces lusitanus DMZ-3 strain with potential to synthesize both insoluble and soluble melanins was detected. Melanins are quite distinguished based on their solubility for varied biotechnological applications. The present investigation reveals the enhanced production of insoluble and soluble melanins in tyrosine medium by a single culture. Streptomyces lusitanus DMZ-3 was characterized by 16S rRNA gene analysis. An enhanced production of 5.29 g/L insoluble melanin was achieved in a submerged bioprocess following response surface methodology. Combined interactive effect of temperature (50°C), pH (8.5), tyrosine (2.0 g/L), and beef extract (0.5 g/L) were found to be critical variables for enhanced production in central composite design analysis. An optimized indigenous slant culture system was an innovative approach for the successful production (264 mg/L) of pure soluble melanin from the droplets formed on the surface of the culture. Both insoluble and soluble melanins were confirmed and characterized by Chemical, reactions, UV, FTIR, and TLC analysis. First time, cytotoxic study of melanin using brine shrimps was reported. Maximum cytotoxic activity of soluble melanin was Lc50-0.40 µg/mL and insoluble melanin was Lc50-0.80 µg/mL.

Purification and cytotoxic assays of four antimicrobial metabolites extracted from Actinomycetes of the soils of Menengai Crater, Kenya

“…The mortality of the brine shrimps increased with increasing concentration of the antimicrobial metabolites. This concurred with previous studies (Kumar et al, 2014;Madhusudhan et al, 2014;Haque et al, 2016). A previous study carried out by Haque et al, (2016) to evaluate the antifungal, hemolytic and cytotoxic potential of ethyl acetate extract of a new marine Streptomyces sp., recorded LC 50 of 17.78 µg/ ml, which was higher than that of the current study.…”

Comprehensive utilization of edible mushroom Auricularia auricula waste residue—Extraction, physicochemical properties of melanin and its antioxidant activity

“…As shown in Table and Figure a, the melanin has good solubility in alkaline solution (such as NaOH solution), but low solubility in distilled water and other organic solvents. The solubility of waste residue melanin was similar to the melanin that from other microorganisms (Kimura, Fukuda, Sanada, Fukuda, Sanada, & Imanaka, ; Madhusudhan et al, ). As shown in Figure b, the temperature had little effect on the stability of waste residue melanin.…”

Biotechnological Potential of Oxidative Enzymes from Actinobacteria

“…The use of water-soluble melanin, such as that produced by several Streptomyces species, could therefore be useful in the treatment of Parkinson's disease. Madhusudhan et al [92] investigated the production and cytotoxicity of extracellular insoluble and soluble melanin that were produced by Streptomyces lusitanus DMZ-3. Whilst their study showed that both the soluble and insoluble melanin were highly cytotoxic, it was observed that the soluble melanin was more biologically active than the insoluble melanin [92].…”

“…Madhusudhan et al [92] investigated the production and cytotoxicity of extracellular insoluble and soluble melanin that were produced by Streptomyces lusitanus DMZ-3. Whilst their study showed that both the soluble and insoluble melanin were highly cytotoxic, it was observed that the soluble melanin was more biologically active than the insoluble melanin [92]. There has also been an increase in using safe, biologically produced compounds in the food industry, for example, the use of silver nanoparticles to control food pathogens [93].…”