Natural Melanin: Current Trends, and Future Approaches, with Especial Reference to Microbial Source

Abstract

Melanin is a universal natural dark polymeric pigment, arising in microorganisms, animals, and plants. There is a couple of pieces of literature on melanin, each focusing on a different issue, the goal of the present review is to focus on microbial melanin. It has numerous benefits with very few drawbacks. The current situation and expected trends are discussed. Intriguing, numerous studies have provoked a serious necessity for a comprehensive assessment of microbial melanin pigments. So that, such review would help scholars from diverse backgrounds to realize the importance of melanin pigments isolated from microorganisms, with this aim in mind, information, and hypothesis from this review could be the paradigm for studies on melanin in the next era.

Experimental modeling and optimization of melanin production by Aureobasidium pullulansNBRC 100716 in carrot peel extract

“…Melanin, a commonly used pigment, is defined as a dark brown or black pigment with high molecular weight formed by oxidative polymerization of phenolic and indolic compounds 2 . The hydrophobic polymer melanin is negatively charged and insoluble in water and organic solvents 3 …”

“…Thanks to its anti‐cancer and anti‐inflammatory properties, melanin can benefit in various medical applications 6 . Considering the increasing demand for melanin pigment due to all this potential for use, it is clear that research on melanin production using microorganisms has significant potential and should be followed more actively 3 . Aureobasidium pullulans is well‐known melanin‐producing microorganism that produces this pigment both intra‐ and extracellularly 7 .…”

“…In a review published in 2022, the importance of microbial natural melanin and its future trends were discussed, and the importance of statistical studies on the optimization of melanin production was emphasized. This review specifically stated that optimization studies are rare 3 . In addition, it was underlined that the future perspectives must devote more attention to the economization of melanin production by using agro‐industrial by‐products as an eco‐friendly alternative 3 .…”

“…This review specifically stated that optimization studies are rare 3 . In addition, it was underlined that the future perspectives must devote more attention to the economization of melanin production by using agro‐industrial by‐products as an eco‐friendly alternative 3 . Finally, although A. pullulans is a well‐known melanin‐producing strain, studies on the melanin production of this strain are also very few.…”

Improved natural melanin production by Aspergillus nidulans after optimization of factors involved in the pigment biosynthesis pathway

“…For example, thin melanin lms can be applied as a semiconductor material on different devices (5), nanoparticles of melanin can be used as nanocarrier drug release (6), and melanin can be incorporated in cosmetic formulations for the protection against oxidative skin damages (7-10) and this pigment can also act as an e cient biosorbent for metal removal/recovery from wastewater (11). Among all organisms, fungi play a valuable and eco-friendly source of natural pigments, including melanin, because they can produce high yields of pigment easily at a low cost, making the bioprocess economically viable on the industrial scale (1,(12)(13)(14)(15). Fungi synthesize different types of melanins by oxidative polymerization of phenolic or indole compounds, such as glutaminyl-3,4-dihydroxybenzene (GDHB), 3,4-dihydroxyphenylalanine (DOPA), 1,8-dihydroxy naphthalene (DHN) or catechol.In a previous study, we characterize the pigment produced by Aspergillus nidulans as 3,4-dihydroxyphenylalanine (DOPA)-melanin according to its physicochemical properties and tests with melanin biosynthesis inhibitors (16).…”