Chitin, Chitinases and Chitin Derivatives in Biopharmaceutical, Agricultural and Environmental Perspective

Chitin is a major structural polysaccharide after cellulose and exists as the most abundant polymer in nature. Chitin is a nitrogen-containing homopolymer of β-(1,4) linked N-Acetylglucosamine. It is a key cell wall component of fungi, also found in a wide range of organisms, including viruses, plants, animals, insect exoskeletons, and crustacean shells. This review focused on the recent developments of applications of chitin, chitinases, and chitin derivatives in biomedicinal, agricultural and environmental perspectives for sustainable development. Chitinases are hydrolytic enzymes responsible for the degradation of chitin and are used in biocontrol against various fungal pathogens and insects to reduce the uses of synthetic fungicides and insecticides. These can serve as sustainable and eco-friendly alternatives to pesticides. Chitinases producing microorganisms are a potential alternative to these chemicals which are present in the soil as a part of the ecosystem. Chitin derivatives and chitinases have significant pharmacological values and are effective as an anti-inflammatory drug, ulcerative colitis, anticancer and gastrointestinal disorders. The significant medical roles of chitinases have also been observed to amplifying the functioning of antifungal drugs during the treatment of fungal diseases. These enzymes can be used for strengthened the human immune system and also employed antifungal creams and lotions as rightly expected. Chitin derivatives have a number of applications in the making of artificial medical articles, including contact lenses, artificial skin, and surgical stitches. These derivatives have been extensively used in making artificial medical products because of its non-toxic, non-allergic, biocompatible, and biodegradable properties. Chitin and its derivatives used for environmental applications comprise bioremediation of organic and inorganic contaminants from soil and water along with biological conversions of chitinous waste to the single-cell proteins, bioethanol, and biofertilizers as well.

Nanofibrillation is an Effective Method to Produce Chitin Derivatives for Induction of Plant Responses in Soybean

Chitin, an N-acetylglucosamine polymer, is well-known to have unique biological functions, such as growth promotion and disease resistance induction in plants. Chitin has been expectedly used for improving crop yield using its functions; however, chitin derivatives, such as chitin oligosaccharide (CO) and chitosan, are widely used instead since chitin is difficult to handle because of its insolubility. Chitin nanofiber (CNF), produced from chitin through nanofibrillation, retains its polymeric structure and can be dispersed uniformly even in water. Here, the effects of CO and CNF on plant responses were directly compared in soybeans (Glycine max) to define the most effective method to produce chitin derivatives for plant response induction. The growth promotion of aerial parts was observed only in CNF-treated plants. The transcriptome analysis showed that the number of differentially expressed genes (DEGs) in CNF-treated soybeans was higher than in CO-treated soybeans. Notably, the expression patterns of DEGs were mostly similar but were strongly induced by CNF treatment as compared with the CO group. These results reveal that CNF can induce stronger plant response to chitin than CO in soybeans, suggesting nanofibrillation, rather than oligomerization, as a more effective method to produce chitin derivatives for plant response induction.

Chitin and Chitinases: Biomedical And Environmental Applications of Chitin and its Derivatives

Disposal of chitin wastes from crustacean shell can cause environmental and health hazards. Chitin is a well known abundant natural polymer extracted after deproteinization and demineralization of the shell wastes of shrimp, crab, lobster, and krill. Extraction of chitin and its derivatives from waste material is one of the alternative ways to turn the waste into useful products. Chitinases are enzymes that degrade chitin. Chitinases contribute to the generation of carbon and nitrogen in the ecosystem. Chitin and chitinolytic enzymes are gaining importance for their biotechnological applications. The presence of surface charge and multiple functional groups make chitin as a beneficial natural polymer. Due to the reactive functional groups chitin can be used for the preparation of a spectrum of chitin derivatives such as chitosan, alkyl chitin, sulfated chitin, dibutyryl chitin and carboxymethyl chitin for specific applications in different areas. The present review is aimed to summarize the efficacy of the chitinases on the chitin and its derivatives and their diverse applications in biomedical and environmental field. Further this review also discusses the synthesis of various chitin derivatives in detail and brings out the importance of chitin and its derivatives in biomedical and environmental applications.

Chemical Modification and Processing of Chitin for Sustainable Production of Biobased Electrolytes

In the present work we report on the development of a novel and sustainable electrolyte based on chitin. Chitin biopolymer was carboxymethylated in simple, mild, and green conditions in order to fine-tune the final properties of the electrolyte. To this end, chitin was modified for various reaction times, while the molar ratio of the reagents, e.g., sodium hydroxide and monochloroacetic acid, was maintained fixed. The resulting chitin derivatives were characterized using various techniques. Under optimized conditions, modified chitin derivatives exhibiting a distinct degree of carboxymethylation and acetylation were obtained. Structural features, morphology, and properties are discussed in relation to the chemical structure of the chitin derivatives. For electrolyte applications, the ionic conductivity increased by three magnitudes from 10−9 S·cm−1 for unmodified chitin to 10−6 S·cm−1 for modified chitin with the highest degree of acetylation. Interestingly, the chitin derivatives formed free-standing films with and without the addition of up to 60% of ionic liquid, the ionic conductivity of the obtained solid electrolyte system reaching the value of 10−3 S·cm−1.