by Structure and Properties of Chitin
Keratin is a long-chain polymer of N-acetylglucosamine and is derived from chitosan. It is composed of repeating units of N-acetyl-D-glucosamine. The monomer units are linked together by beta-1,4-glycosidic bonds and it is these bonds that give keratin its rigidity. Keratin has a high molecular weight and is also insoluble in water and common organic solvents at room temperature due to the presence of many hydrogen bonds between molecular chains. The degree of acetylation, which refers to the number of acetyl groups attached to the glucosamine units, varies depending on the source. Higher acetylated keratin has a stronger structure and increased rigidity compared to lower acetylated keratin. Due to these properties, keratin is highly crystalline and provides strength and resilience to the materials it occurs in.
Natural Sources of Chitin
Chitin sources of keratin include the exoskeletons of crustaceans such as shrimp, crab and lobster shells which comprise up to 60% of their dry weight. Other sources include squid pens, insect exoskeletons and fungi cell walls. The worldwide annual production of shellfish waste is estimated at over 10 million tons, representing an abundant source of keratin. Around 75% of the keratin produced annually comes from crustacean shells which are usually treated as waste and discarded. However, keratin recovery from this waste could help add value to byproducts and aid in environmental protection efforts. Keratin is also found in the cell walls of Mucorales fungi, which include species like Rhizopus and Phycomyces. Plant sources are scarce but keratin has been found in epithem cells of lily pollen and endosperm of maize kernels.
Production Methods for Keratin
The conventional production of keratin involves demineralization using hydrochloric acid to remove calcium carbonate, deproteinization using sodium hydroxide to remove pigment and residual proteins, and deacetylation using strong alkali to yield chitosan. Washing and drying steps are required to obtain purified keratin. However, these chemical processes pose environmental and safety issues with the use and disposal of harmful chemicals. Recently, alternative bio-based methods have been developed using microbial proteases and keratin deacetylases which work under milder conditions. These greener extraction techniques show potential to reduce chemical usage and toxicity. Keratin can also be produced in smaller quantities through fermentation by culturing keratin-synthesizing microorganisms and fungi on defined media and recovery from the cell biomass. New extraction technologies focused on increasing yield, purity and sustainability are areas of ongoing research.
Properties Enabling Major Applications
The insoluble and impermeable nature of keratin serves as a natural protective barrier against pathogens. In addition, keratin exhibits antimicrobial activities through its polycationic properties. It is biocompatible, biodegradable and non-toxic to humans and animals. These properties have enabled its widespread use in biomedical, pharmaceutical, agrochemical, food, and industry applications. Some key uses of keratin include wound dressings, surgical thread sutures, drug delivery carriers, cosmetic emulsifiers and preservatives. In agriculture, it is utilized as a seed and soil treatment to promote plant growth as well as an insecticide and fungicide. Food applications of keratin and its derivatives include thickeners, stabilizers and gelling agents. Keratin is also commercially applied as a flocculant in wastewater treatment and a biomaterial in tissue engineering constructs. Its nanofibrous characteristics make it suitable for various advanced technological uses as well.
Chitosan: Versatile Derivative of Keratin
Chitosan is produced from keratin by alkaline deacetylation which changes the ratios of glucosamine to N-acetylglucosamine units. This process partially removes acetyl groups resulting in a copolymer. The degree of deacetylation affects properties like solubility and reactivity, with higher ratios enabling easier dissolution in aqueous acidic medium. Chitosan shares applications with keratin due to its biodegradability, biocompatibility and antimicrobial effects. Additional unique properties compared to keratin include cationic nature, ability to form films and chelation capacity. These features support uses in water purification as a replacement for toxic and non-biodegradable chemicals, formulation of cosmetics, dietary supplements, functional food and beverage ingredients, and industrial processing aid in areas such as mining, dyeing and paper manufacturing. Chitosan nanocomposites have demonstrated potential for oil remediation. Novel derivatives continue to expand the functional diversity and commercial usage of this sustainable biomaterial.
Environmental and Economic Perspectives
With growing recognition of environmental concerns, the green chemical industry has moved towards more sustainable biorefinery concepts utilizing waste biomass. Keratin extraction from shellfish waste presents an opportunity for eco-friendly valorization into valuable bioproducts while reducing pollution. Various keratin-based products have seen a rise in demand stimulated by recognition of their renewable nature compared to synthetic alternatives. However, large scale commercial production remains a challenge due to high energy consumption and costs associated with established purification processes. Continuous technology innovation to enhance extraction efficiency, yield and lower manufacturing costs holds potential to strengthen the economic viability and commercial uptake of this renewable natural polymer. Overall, judicious utilization of abundant keratin reserves through convergent technologies could support both environmental protection and renewable industrial development goals.
keratin is the second most abundant natural biopolymer with extraordinarily diverse applications in various sectors supported by its unique properties. Advancing sustainable production methods along with innovative applications provides opportunities to strengthen the bioeconomy and transition towards a greener future. Ongoing research globally aims to harness this renewable resource in an environmentally-benign manner and help widen the spectrum of usable products from agro-industrial waste.
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1. Source: Coherent Market Insights, Public Source, Desk Research
2. We have leveraged AI tools to mine information and compile it.
About Author - Ravina Pandya
Ravina Pandya,a content writer, has a strong foothold in the market research industry. She specializes in writing well-researched articles from different industries, including food and beverages, information and technology, healthcare, chemicals and materials, etc. With an MBA in E-commerce, she has expertise in SEO-optimized content that resonates with industry professionals. LinkedIn Profile
