Microbial production of melanin and its various applications

Abstract

Melanins are natural biopolymers that are known to contribute to different biological processes and to protect organisms from adverse environmental conditions. During the past decade, melanins have attracted increasing attention for their use in organic semiconductors and bioelectronics, drug delivery, photoprotection and environmental bioremediation. Although considerable advances in these fields have been achieved, real-world applications of melanins are still scarce, probably due to the limited and expensive source of natural melanin. Nevertheless, recent biotechnological advances have allowed for relatively large-scale production of microbial melanins, which could replace current commercial melanin. In this review, we first describe different melanin sources and highlight the advantages and disadvantages of each production method. Our focus is on the microbial synthesis of melanins, including the methodology and mechanism of melanin formation. Applications of microbial melanins are also discussed, and an outlook on how to push the field forward is discussed.

Melanin: Production from Cheese Bacteria, Chemical Characterization, and Biological Activities

“…As the current trend around the world is shifting to the use of eco-friendly commodities, demand for natural dyes is increasing. The diverse biological roles of melanin in bacteria and fungi have been extensively reported in the literature [7]. Despite the fact that melanins are produced by a wide variety of microorganisms, they are not considered essential for its growth, being required in order to enhance the ability of the producing species to compete and survive under certain environmental conditions [8].…”

Fungal Melanins and Applications in Healthcare, Bioremediation and Industry

“…When extracting fungal melanins for human applications, eumelanins are often preferred as allomelanins are attached to the inner side of the fungal cell walls [ 46 ]. In contrast, eumelanins are used by fungi to neutralize toxic environmental compounds, making these melanins easier to extract extracellularly [ 46 ]. Currently, there are several different methods used to culture melanotic fungi, but most methods use a combination of tyrosine and metal ions [ 46 ].…”

“…In contrast, eumelanins are used by fungi to neutralize toxic environmental compounds, making these melanins easier to extract extracellularly [ 46 ]. Currently, there are several different methods used to culture melanotic fungi, but most methods use a combination of tyrosine and metal ions [ 46 ]. Recently, fungal strains were genetically modified to become more melanotic for extraction purposes, principally by overexpressing genes for tyrosinases [ 33 ].…”

The Dark Side of Fungal Competition and Resource Capture in Wood: Zone Line Spalting From Science to Application

“…Armillaria spp.) form melanin through 4, 3,4-dihydroxyphenylalanine (DOPA, resulting in eumelanin) and cysteinyl-DOPA (resulting in pheomelanin) [53,73,74]. Extracellular secretion of melanin minimises degradation of plant cells and supports structural integrity of zone lines and fungus survivability [4,76].…”