Preparation and characterisation of chitosan from Penicillium chrysogenum Thom for decolourisation of Congo red dye in aqueous solution

Abstract

This work investigated the removal efficiency of Congo red dye (CRD) from aqueous solution using chitosan prepared from the biomass of Penicillium chrysogenum Thom. CRD is a benzidine - based anionic diazo dye known to be carcinogenic at low concentration. Chitosan was prepared from the mycelium of P.chrysogenum through the process of deproteination and deacetylation; and the chitosan was characterised using Fourier transform infrared spectroscopy (FT-IR) analysis through which the degree of deacetylation (DD) was estimated. Adsorption study was carried out in a slurry batch system at ambient temperature (28 ± 1oC). The percentage yield of chitosan from the fungus was 12.2% while 82.4% DD was achieved. The FT-IR spectrum showed that chitosan contained amide carbonyl band as a measure of N-acetyl group, alkyl groups and hydroxyl groups; the spectrum of P. chrysogenum-based chitosan corresponded to the pattern of the commercial chitosan used as control. The commercial and P. chrysogenum-based chitosan attained decolourisation efficiency of 95.2% and 84.6% respectively, which gives the indication that chitosan from P. chrysogenum biomass, can effectively remove CRD from aqueous solution.Keywords: Adsorption, Chitosan, Congo red, Deacetylation, Penicillium chrysogenum