Purpose of ReviewThis review imparts the information on melanin as a multifunctional biomolecule, emphasizing the diversity of sources like microbial, plant, and human, and accentuating its potential as a sustainable material. It deliberately focuses on current advances in utilizing melanin for inventive applications in important areas such as food, cosmetics, environmental improvement, and agriculture, as well as its increasing significance in promoting eco-friendly and industrial solutions.Recent FindingsMelanin derived from microbial, plant, and human sources has a broad spectrum of bioactivities, which includes protection from UV radiation, strong antioxidant capabilities, and the strong ability to affiliate and neutralize environmental contaminants. Recently its natural origin and biocompatibility have caught the eye in its usage as a food coloring and preservation. Not only this, it is also known to create a spark in the cosmetic industry by providing skin protection, pigmentation balance, and anti-aging effects, with both plant- and human-derived melanin playing their important roles.Environmentally, microbial and plant-based melanin built a strong resilience in the elimination of heavy and toxic metals and compounds. In agriculture, microbial melanin is well known for improving soil health in addition to increasing plant tolerance to stress and shielding biocontrol chemicals from UV destruction and showing their high capacity and significant role in different industries, making it one of the most promising byproducts of the cellular process.Recent FindingsMelanin derived from microbial, plant, and human sources has a broad spectrum of bioactivities, which includes protection from UV radiation, strong antioxidant capabilities, and the strong ability to affiliate and neutralize environmental contaminants. Recently its natural origin and biocompatibility have caught the eye in its usage as a food coloring and preservation. Not only this, it is also known to create a spark in the cosmetic industry by providing skin protection, pigmentation balance, and anti-aging effects, with both plant- and human-derived melanin playing their important roles.Environmentally, microbial and plant-based melanin built a strong resilience in the elimination of heavy and toxic metals and compounds. In agriculture, microbial melanin is well known for improving soil health in addition to increasing plant tolerance to stress and shielding biocontrol chemicals from UV destruction and showing their high capacity and significant role in different industries, making it one of the most promising byproducts of the cellular process.SummaryMelanin, derived from different sources-microorganisms, plants, and humans-represents a flexible and sustainable biomaterial that is becoming increasingly important in the various fields. Its multifunctional qualities make it extraordinary application for use in food preservation, cosmetics, environmental improvement, and sustainable agriculture. This review summarizes melanin's potential for long-term innovation and industrial progress by amalgamating the ideas from several biological sources.

Pigments are an essential part of everyday life on Earth with rapidly growing industrial and biomedical applications. Synthetic pigments account for a major portion of these pigments that in turn have deleterious effects on public health and environment. Such drawbacks of synthetic pigments have shifted the trend to use natural pigments that are considered as the best alternative to synthetic pigments due to their significant properties. Natural pigments from microorganisms are of great interest due to their broader applications in the pharmaceutical, food, and textile industry with increasing demand among the consumers opting for natural pigments. To fulfill the market demand of natural pigments new sources should be explored. Cold-adapted bacteria and fungi in the cryosphere produce a variety of pigments as a protective strategy against ecological stresses such as low temperature, oxidative stresses, and ultraviolet radiation making them a potential source for natural pigment production. This review highlights the protective strategies and pigment production by cold-adapted bacteria and fungi, their industrial and biomedical applications, condition optimization for maximum pigment extraction as well as the challenges facing in the exploitation of cryospheric microorganisms for pigment extraction that hopefully will provide valuable information, direction, and progress in forthcoming studies.

Phenols, ubiquitous environmental contaminants found in water, soil, and air, pose risks to organisms even at minimal concentrations, and many are classified as hazardous pollutants. Skin pigmentation is a natural shield against ultraviolet-induced DNA damage and oxidative stress, pivotal in reducing skin cancer incidences. Studies on B16F10 melanoma cells and zebrafish offer valuable insights into potential therapeutic avenues for melanoma in the context of phenol exposure. Upon phenol treatment, there was a marked decrease in melanin content and melanogenesis-associated protein expression, such as tyrosinase and the microphthalmia-associated transcription factor (MITF) in these melanoma cells. Additionally, phenols led to diminished p38 phosphorylation, amplified extracellular signal-regulated kinase (ERK) phosphorylation, and curtailed melanin expression in zebrafish. These observations underscore the detrimental impact of phenols on melanogenesis and propose a mechanism of action centered on the ERK/p38 signaling pathway. Consequently, our data spotlight the adverse effects of phenols on melanogenesis.

The mat-forming fruticose lichens Cladonia stellaris and Cetraria islandica frequently co-occur on soils in sun-exposed boreal, subarctic, and alpine ecosystems. While the dominant reindeer lichen Cladonia lacks a cortex but produces the light-reflecting pale pigment usnic acid on its surface, the common but patchier Cetraria has a firm cortex sealed by the light-absorbing pigment melanin. By measuring reflectance spectra, high-light tolerance, photosynthetic responses, and chlorophyll fluorescence in sympatric populations of these lichens differing in fungal pigments, we aimed to study how they cope with high light while hydrated. Specimens of the two species tolerated high light equally well but with different protective mechanisms. The mycobiont of the melanic species efficiently absorbed excess light, consistent with a lower need for its photobiont to protect itself by non-photochemical quenching (NPQ). By contrast, usnic acid screened light at 450-700 nm by reflectance and absorbed shorter wavelengths. The ecorticate usnic species with less efficient fungal light screening exhibited a consistently lower light compensation point and higher CO2 uptake rates than the melanic lichen. In both species, steady state NPQ rapidly increased at increasing light with no signs of light saturation. To compensate for less internal shading causing light fluctuations with a larger amplitude, the usnic lichen photobiont adjusted to changing light by faster induction and faster relaxation of NPQ rapidly transforming excess excitation energy to less damaging heat. The high and flexible NPQ tracking fluctuations in solar radiation probably contributes to the strong dominance of the usnic mat-forming Cladonia in open lichen-dominated heaths.