Green and eco-friendly approaches for the extraction of chitin and chitosan: A review.

Chitin and chitin-based biomaterials: A review of advances in processing and food applications.

Halophilic archaea are known to have proteolytic activity and also has the capability to reduce ammonia from the processing discards. In this study, two proteolytic strains of halophilic archaea (Halobacterium salinarum and Halococcus dombrowskii) were evaluated for its deproteinization efficiency for isolating chitin. Fresh and cooked vannamei shrimp shell waste was fermented for a period of 16 days with regular samplings. Initial alkaline pH of the treatments had reduced drastically within 4 days and was maintained throughout the fermentation period. Total nitrogen and residual protein levels reduced gradually, while chitin nitrogen increased proportionally during the fermentation process due to proteolytic activity of haloarchaea. Total halophile count had increased over the fermentation period and maximum colony forming units (8.05 log CFU/mL) was found in T4. Among the two strains Halococcus dombrowskii, inoculated with cooked shell waste (T4) exhibited the highest proteolytic activity with 98% deproteinization. Correspondingly, 95% carotenoprotein removal was achieved by H. dombrowskii. As no demineralization was observed during the investigation period, the shell residue was further demineralized for chitin preparation. This study represents a novel, eco-friendly deproteinization technique of shrimp shell waste using halophilic archaea.

Application of extreme halophilic archaea as biocatalyst for chitin isolation from shrimp shell waste

Sustainable processes for treatment and management of seafood solid waste.

The substitution of synthetic raw materials with renewable feedstock is fueling a lot of interest to drive new scientific and technical advancements that underpin this strategy. In this context and looking at the broad prospect of chitosan, herein, we proposed a facile, economical, and novel strategy to process high-yield (44% ± 3) chitosan from waste crab shells and apply the processed chitosan to fabricate a durable, multifunctional, ecofriendly superhydrophobic coating. The coating was developed by binding the amines of chitosan and a long-chain polymer, octadecylamine using a cross-linking agent (glutaraldehyde). Applying the coating onto intrinsically hydrophilic polyester fabric and typical surgical-grade cotton yielded superhydrophobic materials with water contact angles of 158.6 and 161.4° (± 3), respectively. A preliminary study revealed that the coating could endure multiple cycles of laundry (60×), sandpaper abrasion (55×), and tape peel test (80×) with little diminution in the superhydrophobic property. Interestingly, any decrease in the superhydrophobicity could be restored after ironing the fabrics for 2 min, indicating that the effect was reversible. Furthermore, the coating could transform an ordinary hydrophilic polyurethane sponge into an excellent superhydrophobic–superoleophilic absorbent, which can rapidly absorb and separate a variety of organic solvents and oils from oil/water mixtures. 

Adharsh Joy

Papers

Characterization of chitin extracted from enzymatically deproteinized Acetes shell residue with varying degree of hydrolysis