Mold Chitosan production using Ficus microcarpa fruit

Abstract

Aims: The main objective of this work was the valorization of Ficus microcarpa fruit, an inedible fruit with a high nutritional value in the production of chitosan by Aspergillus niger. Methods: A surface and submerged growth of Aspergillus niger were carried out using the Ficus microcarpa fruit syrup. 3 106 spores/ 50 ml were inoculated. Chitosan production was conducted at 37° C for 14 days using both surface and submerged fermentation modes. The growth of Aspergillus niger was followed by spore count on a Malassez cell. The evolution of pH and the consumption of total sugars in the mixture were monitored. Chitosan was extracted after degumming with NaOH 10N and centrifugation. Results: During the first days, the fungal growth was exponential with maximum growth rates of 10.06 g/L/day and 12.05g/L/day respectively for the surface and submerged cultures. The mycelial growth was largely linked to a high intake of sugars. The chitosan production in glucose syrup was significantly lower than the production using Ficus microcarpa syrup. This syrup allowed producing 41 g/L of chitosan for the surface culture and 37.2g/L for the submerged culture. Infrared analysis of chitosan powders showed similar spectra to those of commercial and shrimp chitosan. This first work is a contribution to a better valorization of a bioresource. Keywords: Aspergillus niger, culture, chitosan, Ficus microcarpa fruit, syrup.