Dual extraction of crustacean and fungal chitosan from a single Mucor circinelloides fermentation

Abstract

Mucor circinelloides is a fungus that has been reported to produce ethanol, oil, protein, phosphate and glucosamine, depending on the available nutrients and cultivation conditions. Due to its ability to produce extracellular proteases, it is able to ferment polypeptides and amino acids broken down from various protein sources. In this study, we attempted to culture the Mucor circinelloides on waste substrates to deproteinize prawn shells for the extraction of chitin and subsequently extract chitosan from its fungal cell wall in a concurrent fermentation. The physio-chemical properties of the extracted crustacean chitin and fungal chitosan were determined by Fourier Transform Infrared Spectroscopy (FTIR) and Elemental Analysis (EA). We found that Mucor circinelloides grown on okara and coffee waste behaved as an excellent protease producer and successfully extracted chitin from prawn shells with a degree of deacetylation of 69.94% and 68.82%, respectively, comparable to commercial chitin (70.46%). The fungal chitosan extracted from the fermentation of Mucor circinelloides on red grape pomace substrate showed a degree of deacetylation of 61.05%, comparable to commercial chitosan (64.00%). Our results suggested feasibility of extracting chitosan from seafood waste-streams using cost-effective microbial fermentation.