Abstract
An actinobacteria strain was isolated from Algerian Sahara soil and assigned to Streptomyces cyaneofuscatus Pridham et al. 1958 species. This strain was selected for its ability to produce melanin exopigments in liquid and solid media. Melanin synthesis was associated with tyrosinase activity and the enzyme from this strain was isolated and biochemically characterized. Synthetic melanin was then enzymatically produced using the S. cyaneofuscatus Pridham et al. 1958 tyrosinase. As this enzyme showed a higher diphenolase activity, a synthetic melanin from the enzymic oxidation of 3,4-dihydroxyphenylalanine (dopa) was obtained by the use of a Trametes versicolor (L.) Lloyd laccase for comparison. The natural and synthetic pigments were physico-chemically characterized by the use of ultraviolet (UV)-Visible, and Fourier transform infrared (FT-IR) and multifrequency electron paramagnetic resonance (EPR) spectroscopies. All the melanin samples displayed a stable free radical when analyzed by X-band EPR spectroscopy. Once the samples were recorded at Q-band EPR, a copolymer derived from a mixture of different constituents was evident in the natural melanin. All radical species were analyzed and discussed. The use of water-soluble melanin naturally produced by S. cyaneofuscatus Pridham et al. 1958 represents a new biotechnological alternative to commercial insoluble pigments.
Highlights
Melanins are pigments exhibiting unique properties as ultraviolet (UV)-visible light absorbers, free radical scavengers, and metal ions chelators [1,2,3,4,5]
A strain belonging to the Streptomyces cyaneofuscatus Pridham et al 1958 species, hereinafter
EPRAldrich signal(Milano, pattern, clearly indicating chemicals and Tv laccase were obtained from Sigma and used without the presence of more than one radical species, of which identified as pheomelanin further purification
Summary
Melanins are pigments exhibiting unique properties as ultraviolet (UV)-visible light absorbers, free radical scavengers, and metal ions chelators [1,2,3,4,5] Computational models have been successfully used to investigate eumelanins as polymers that have a high level of chemical and geometrical disorder, so that the term polymer can be used to refer to their polymer-like properties [9,10] Their monotonously increasing light absorption from the visible to ultraviolet region has supported this description [9]. Structural tuning could be used to produce melanins mimicking properties characteristic of other natural relevant molecules, such as the strong adhesive properties of mussel proteins [1]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
