Feasibility study on optimizing chitosan extraction and characterization from shrimp biowaste via acidic demineralization

Abstract

Utilizing a large portion of shrimp biowaste into valuable materials such as chitosan is one of the most required actions to sustain shrimp waste and promote green deal targets and circular economy principles in the aquaculture industry. This research aimed to optimize acidic demineralization using various HCl concentrations of 1, 2, 3, 4, 5, and 10% on chitosan extraction and characterization of morphological and physicochemical properties. Chitosan production with a high deacetylation degree (89.7–93.8%) for all samples was confirmed by FT-IR spectroscopy compared to commercial chitosan. The ash content, moisture content, and chitosan yield were in the ranges of (0.24–0.89%), (0.26–5.1%), and (15.1–51.3%), respectively. Furthermore, XRD showed that commercial chitosan had a completely amorphous structure. In contrast, the isolated chitosan samples showed a low crystallinity index (3.57–19.58%) due to the formation of natrite (Na₂CO₃) and thermonatrite (Na₂CO₃.H₂O) as indicated by SEM–EDS. Additionally, this study found that chitosan production can be optimized from white Pacific shrimp shells (Litopenaeus vannamei) with high resemblance to commercial chitosan using the optimal acidic demineralization concentrations of 1–3% hydrochloric acid at room temperature under stabilized conditions of deproteinization and deacetylation processes. Furthermore, future research will focus on optimizing the deproteinization and deacetylation stages of the chemical extraction of chitosan using the optimal demineralization conditions found in the current study. Additionally, utilizing the byproducts of the chemical extraction stages as liquid fertilizers in agriculture develops an integrated industrial sustainable solution for shrimp waste management.