Zero Hunger (SDG 2), Good Health & Well-being (SDG 3)
Extraction of Chitosan from crab shells using an aqueous extract of wood ash for the deacetylation of chitin: an innovative, eco-friendly, and low-cost method
Juliao Armando Monjane* Eduardo Mondlane University, Mozambique
The importance of chitosan has grown significantly over the last years due to its medicinal, agricultural, and industrial applications and biodegradability properties. The present work describes for the first time, the preparation of chitosan from chitin using wood ash aqueous extract as an alkaline medium. Chitin was obtained from crab shells in a microbial fermentation process using fish viscera for protease. Pilled and milled sweet potatoes and cassava water extracts were used separately in the deproteinization and demineralization steps as sources of carbon. The obtained chitin samples were then converted into the respective chitosan samples by an innovative, low-cost, and eco-friendly method using an aqueous extract (pH=12.4) prepared from wood ashes, instead of the chemical process using sodium hydroxide solution in the deacetylation of chitin. The presence of chitosan was determined by the analysis of the FTIR spectrum of both samples. The degree of acetylation was ranging from 77.3 to 83.2%, based on the IR analysis of absorption bands at 3456 and 1636 cm- 1 , and from 75.4 to 84.1% based on the potentiometric titration. The average molecular weight (192.1 to 194.3 kDa) was determined using the viscometer method. The obtained chitosan samples showed to enhance the grain yield on maize (6.0 t.ha - ¹) by applying at a concentration of 25% when compared with the positive control-Manconzeb (4.5 ha - ¹). The obtained chitosan will contribute to Zero Hunger by enhancing food security to increase income and consequently, it will allow access to Good Health and Well-being when it is used as a biopesticide and/or biofertilizer.
P27
© The Author(s), 2023
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