Response surface optimization, purification, characterization and short-chain chitooligosaccharides production from...

Chitin, recovered in huge amounts from coastal waste, may biocatalytically valorized for utilization in food and biotech sectors. Conventional chemical-based conversion makes use of significant volumes of hazardous acid and alkali. Alternatively, enzymes offer better process control and generation of homogeneous products. Process variables were derived to achieve augmented levels of chitinase (3.8809 Ul^-1 h^-1) productivity from a novel thermophilic fungal strain Thermomyces dupontii, ITCC 9104 following incubation (96 h, 45 °C). An acidic thermostable chitinase TdChiT having molecular mass of 60 kDa has been purified. Optimal TdChiT activity has been demonstrated at 70 °C and pH 5. Notably decreased activity over a broad range of temperature and pH was observed following deglycosylation. Half-life, activation energy, Gibbs free energy, enthalpy and entropy for denaturation of TdChiT at its optimum temperature were 197.40 min, 105.48 kJ mol^-1, 100.59 kJ mol^-1, 102.64 kJ mol^-1 and 5.95 J mol^-1 K^-1. TdChiT has specificity towards colloidal chitin and (GlcNAc)_2-4. Metal ions viz. Mn²⁺, Ca²⁺ and Co²⁺ and nonionic surfactants notably enhanced chitinase activity. Thin layer chromatography analysis has revealed effective hydrolysis of colloidal chitin and (GlcNAc)_2-4. TdChiT may potentially be employed for design of better, eco-friendly and less resource-intensive industrial procedures for upcycling of crustacean waste into value-added organonitrogens.