Natural Products & Green Chemistry Division, CSIR-Central Salt and Marine Chemicals Research Institute (CSIR-CSMCRI), Council of Scientific and Industrial Research (CSIR), Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.
Institute of Applied Chemistry and Department of Chemistry, Hallym University, Chuncheon 200702, Republic of Korea.
Biotechnol Adv. 2021 Dec;53:107773. doi: 10.1016/j.biotechadv.2021.107773. Epub 2021 May 20.
Melanin is a common name for a group of biopolymers with the dominance of potential applications in medical sciences, cosmeceutical, bioremediation, and bioelectronic applications. The broad distribution of these pigments suggests their role to combat abiotic and biotic stresses in diverse life forms. Biosynthesis of melanin in fungi and bacteria occurs by oxidative polymerization of phenolic compounds predominantly by two pathways, 1,8-dihydroxynaphthalene [DHN] or 3,4-dihydroxyphenylalanine [DOPA], resulting in different kinds of melanin, i.e., eumelanin, pheomelanin, allomelanin, pyomelanin, and neuromelanin. The enzymes responsible for melanin synthesis belong mainly to tyrosinase, laccase, and polyketide synthase families. Studies have shown that manipulating culture parameters, combined with recombinant technology, can increase melanin yield for large-scale production. Despite significant efforts, its low solubility has limited the development of extraction procedures, and heterogeneous structural complexity has impaired structural elucidation, restricting effective exploitation of their biotechnological potential. Innumerable studies have been performed on melanin pigments from different taxa of life in order to advance the knowledge about melanin pigments for their efficient utilization in diverse applications. These studies prompted an urgent need for a comprehensive review on melanin pigments isolated from microorganisms, so that such review encompassing biosynthesis, bioproduction, characterization, and potential applications would help researchers from diverse background to understand the importance of microbial melanins and to utilize the information from the review for planning studies on melanin. With this aim in mind, the present report compares conventional and modern ideas for environment-friendly extraction procedures for melanin. Furthermore, the characteristic parameters to differentiate between eumelanin and pheomelanin are also mentioned, followed by their biotechnological applications forming the basis of industrial utilization. There lies a massive scope of work to circumvent the bottlenecks in their isolation and structural elucidation methodologies.
黑色素是一组生物聚合物的通用名称，其主要潜在应用领域包括医学科学、化妆品、生物修复和生物电子应用。这些色素的广泛分布表明它们在各种生命形式中具有抵抗非生物和生物胁迫的作用。真菌和细菌中的黑色素生物合成是通过酚类化合物的氧化聚合来进行的，主要通过两条途径，即 1,8-二羟基萘 [DHN] 或 3,4-二羟苯丙氨酸 [DOPA]，从而产生不同类型的黑色素，即真黑色素、褐黑色素、异黑色素、焦黑色素和神经黑色素。负责黑色素合成的酶主要属于酪氨酸酶、漆酶和聚酮合酶家族。研究表明，通过操纵培养参数，结合重组技术，可以提高黑色素的产量，实现大规模生产。尽管已经做出了巨大的努力，但黑色素的低溶解度限制了提取程序的发展，而其异构结构的复杂性则阻碍了结构解析，限制了其生物技术潜力的有效开发。为了推进黑色素在不同应用中的有效利用，人们对来自不同生命分类群的黑色素进行了无数研究，以提高对黑色素的认识。这些研究促使人们迫切需要对微生物中分离出的黑色素进行全面综述，以便涵盖黑色素的生物合成、生物生产、特性和潜在应用等方面的综述，帮助来自不同背景的研究人员了解微生物黑色素的重要性，并利用综述中的信息来规划黑色素的研究。基于此目的，本报告比较了传统和现代的环境友好型黑色素提取方法。此外，还提到了区分真黑色素和褐黑色素的特征参数，以及它们的生物技术应用，这些应用构成了工业利用的基础。在其分离和结构解析方法方面，仍有大量工作需要克服瓶颈。
