Biological application of bacterial pigments
Microorganism (fungi, yeasts and bacteria) are abundant in nature; the advantages of pigment synthesis from microorganisms include easy and rapid growth in a low-cost culture medium. Generally, bacterial pigments are used in cosmetics, food, pharmaceuticals and textile industries. Microbes producing natural colour molecules such as bacteriochlorophylls, carotenoids, flavins, indigoids, melanins, phenazines, monazines, prodigiosin, quinones, and violacein use them as by-products. The major requirements for various biotechnological applications in commercial businesses are pigment resources, production rate, transportation, pricing, sustainability, palatability, durability, effectiveness, legislative and regulatory permission and customer demand (C. H. Ramesh et al., 2017). Colourful and weather-resistant pigment-producing microorganism carbon sources like red rice, wine and red bean curd are used for the production of microbial pigments. For example, microbial colourants are already used in the fish business to increase the pink colour of farmed salmon (Soliev et al., 2011).The usage of 𝛽- Carotene in vegetable oils as a solution or suspension in margarine colouring, baked goods and emulsions used in prepared foods or micro-encapsulated beadlets. It’s also used in drinks like orange juice, confectionery and other ready-to-eat meals. Due to photosensitivity associated with quinidine consumption, which absorbs the hazardous short wavelength part of the light spectrum, carotenoids have been shown to protect against genetic disorders like erythropoietic protoporphyria (EPP) and erythema (skin reddening) (Kirti et al., 2014).
Prodigiosin is a critical bioactive compound with common applications in the food, pharmaceutical, cosmetic and textile industries. Prodigiosin has a broad range of biological activities, including antibacterial, antifungal, and antimalarial properties (Y. Zhao et al., 2020). The bacteria that produce prodigiosin and violacein offer strong defence and deterrence against bacterivores like protozoa and worms, as well as survival advantages against rivals and predators. They also offer selection advantages versus other bacteria in the area. Cancer is the world’s second greatest cause of death, and despite the development of new therapies for specific malignancies, it remains as deadly as ever. Prodigiosin has been shown to kill human cancer cell lines by a process known as programmed cell death, or apoptosis. In addition to human lung cancer cells, gastric cancer cells, multidrug-resistant breast cancer cells, colorectal cancer cells, and glioblastoma multiform cancer cells in chronic lymphocytic leukaemia. This pigment has a suppressive effect on T-cell proliferation while having no effect on B-cell proliferation (Choi et al., 2021).
The UV absorption range of 290 to 320 nm was boosted by violacein, indicating that adding it to other sunscreen components could boost the protective factors (SPF). Aloevera leaf extract and Cucumis sativus, both of which have photo protective properties are included as well. The properties of violacein stated above suggest that it could be used as a photo protectant in biomedical applications. The purple colour of violacein, which is used in the textile industry, is a distinguishing property of this pigment made from growing Chromobacterium andJanthinobacterium. It is a specific culture used for dyeing fibrous materials and nylon textiles that has larvicidal and pupicidal effects on some insects. By suppressing the growth of pathogenic fungus and parasitic nematodes that cause plant damage, it was also effective in controlling microdochium, stem rot, damping off fungus, and damping-off of bean sprouts. Plant mycosis and plant-parasitic nematode diseases can be prevented with insecticides containing violacein and its derivatives (Choi et al., 2020).
Quinones are used for scent, flavour, defence, signalling, colour, and energy transduction, as well as acting as an intermediary between a plant and its environment. Antifungal, antibacterial, antioxidant, anti-cancer, anti-inflammatory, laxative, anti-allergens, and anti-moth activities of natural quinone components have found applications in pharmacology for promoting cytoprotection in humans. It is also utilised as histology stains and insect repellents, as well as in engineering and technology for metallic corrosion protection, pH indicators, and industrial colouring agents. Quinone dyes have been used as sensors, pigments, inks, and dyes for leather, wood, medicine, food and textiles as well as for histological staining, rust prevention on metal surfaces, and increasing the conversion efficiency of solar cells (Dulo et al., 2021).