Sustainable chitin extraction from Neurospora intermedia grown on pistachio waste: Optimization and high-efficiency...

The accumulation of pistachio waste poses significant environmental challenges. A sustainable strategy for managing this waste involves repurposing it as a culture medium for filamentous fungi, offering dual benefits of waste reduction and the synthesis of value-added products. This study presents, for the first time, the extraction of chitin from Neurospora intermedia grown on pistachio waste. A three-step chemical process (deproteinization, demineralization, and decolorization) was optimized, yielding a chitin extract with 20.8 % yield and 85.4 % purity under mild and environmentally friendly alkaline conditions (1 M sodium hydroxide, 95 °C, for 90 min), positioning this method as a greener alternative to conventional, harsher extraction protocols. Characterization techniques, including XRD, SEM, TGA, BET, and FTIR, confirmed that the extracted chitin is similar to commercial-grade chitin. The potential application of chitin as an adsorbent for hexavalent chromium removal was evaluated under various operating conditions. Under optimal parameters (pH 1, 5 g/L adsorbent dosage, and 100 mg/L initial pollutant concentration), a removal efficiency of 99.35 % and an adsorption capacity of 32.68 mg/g were achieved within 60 min, following pseudo-second-order kinetics and the Langmuir isotherm model. This study demonstrates that low-value biomass can be converted into a high-performance biosorbent, exhibiting promising potential for environmental applications and potential future use in industrial wastewater treatment.