Applications of fungal pigments in biotechnology

The rapid development is leading the demand of colors in biotechnology related to food, textile, medicine and cosmetics. The health hazards of synthetic colors compel industries to adapt natural pigments. “Among them; microbial pigments most important and very diverse in nature.” In this group the fungal pigments are of high demand due to mostly being extracellular metabolites, easy to extract and have enormous biotechnological applications. “Almost all genus of fungi produce efficient amount of pigment which depend and vary from species to species. Yeast, basidiomycetes, Zygomycetes, filamentous fungi, endophytic fungi, marine fungi and halophiles are most important groups which produce useful pigments. The pigments mostly found in kingdom fungi include melanin, phenazines, flavins, carotenoids, violacein, indigo, ankaflavins, canthaxanthin, prodigiosin and moascins. These pigments are being extracted on industrial scale for many biotechnological purposes. This review is intended to highlight the importance of pigments produced by fungi. The research on pigments producing fungi can lead to the development of industries related to textile, food, medicine, and cosmetics.


Introduction
The chemical compounds which absorb light in the wavelength range of the visible region are known as pigment, which can be natural, synthetic, or inorganic [1, 2]."Natural pigments are found in all kingdoms of algae, fungi, plants, animals" [3].All advance animals including human communicate and contact surrounding by the help of pigments that is why they are of high utility for living organisms [3].The previous studies show that microbes and plants have the ability to produce some natural products, their chemistry and composition depends on the organism excreting it.These kinds of natural products are mostly secondary metabolites.Fungi have the ability to produce different secondary metabolites including cephalosporin, penicillin, statins, ergotrate, pigments and other compounds [4].Among microbes, fungi have the ability to produce potent pigments which can be used as dye or as a food colorant [5].A wide range of pigments are produced by fungi, exhibiting many biological properties beside some of being cytotoxic [6].The studies show that pigment production by filamentous fungi is gaining interest amongst food colorants, textiles and cosmetic industries due to their properties [7].

History of pigments
The art of dyeing and coloring has long history.It has been in use since the Bronze age.The earliest use of natural dyes was first recorded in China dated back 2600 before Christ (BC).In 2500 BC dyeing technology was adopted in Indian Subcontinent, being evident in ruins of Mohenjodaro and Harappa civilization of 3500 BC.Evidence of wrapping mummies in colored cloths has been found in Egypt.Different dyes such as madder, wood, weld, Brazil wood, Dark reddish purple and indigo was known by fourth century anno Domini (AD).Even Brazil has been named by the wood found in there

Microbial pigment
The natural pigment extracted from microorganisms is termed as microbial pigment.Food and textile colorants are being extracted by bacteria, algae and fungi.These microbes are promising species to produce natural colors [11].

Fungal pigment
The kingdom fungi are full of diverse and unique group of organisms which produce various kinds of biotechnologically important metabolites.Among fungal species Monascus Purpureus produce variety of secondary metabolites which is usually colored naturally.This fungal species is also called red-purple yeast [12], and is reported to produce red (azaphilones), yellow pigment called ankaflavine and monascine, purple

Conclusion
The kingdom fungi are diverse group of prokaryotes.It produces extracellular metabolites which carry enormous biotechnological applications.The fungal pigment is one of those bio-active compounds.Almost all groups of fungi produce pigments of different colors and characteristics.The most important fungal pigments include carotenoids, melanin, phenazines, violacein, flavins, quinones, indigo etc.These pigments carry antibacterial, antifungal, anti-cancerous and antioxidant potential.Many fungal pigments show a great performance in textile, food and cosmetics industries.The health hazards and environmental concerns of synthetic pigments compel researchers to work and find substitute of such synthetic pigments.To overcome hazards of such issues, extracting fungal pigment and its use could be best solution, as it takes less efforts and cost.
[8].The art and designing of coloring spread widely with development of civilization [9].This was main reason for studies on bio-colorant which enhanced due to their multiple functions in daily life [10].Pigments can be divided into many classes on the basis of their nature such as natural pigments, synthetic pigments and inorganic pigments.Synthetic pigments are sourced by laboratories, inorganic pigments occur naturally in ores and natural pigments are produced by plants, microorganisms, animals and fungi [2].

Table 1 . Some representative species of fungi and their biotechnological applications
Among all microbes, fungi have ability to release pigments in large quantity.They are valuable sources of natural pigments after plants.Fungi release pigment in cheap culture medium, thus making it feasible to use on industrial level.They are eco-friendly way to produce and use bio-colorants [6].Some of the fungal pigment applications are mentioned in (Table1).