Physicochemical Properties and Bioactivity of Fungal Chitin and Chitosan

Abstract

Chitinous material was extracted from mycelia of Aspergillus niger and Mucor rouxii grown in yeast peptone dextrose broth for 15 and 21 days, respectively. The extracted material was characterized for purity, degree of acetylation, and crystallinity and tested for antibacterial and eliciting properties. The maximum glucosamine level determined in the mycelium of A. niger was 11.10% dw and in the mycelium of M. rouxii was 20.13% dw. On the basis of the stepwise extraction of freeze-dried mycelia, it appeared that M. rouxii mycelia contained both chitin and chitosan, whereas A. niger contained only chitin. The yields of crude chitin from A. niger and M. rouxii were 24.01 and 13.25%, respectively, and the yield of chitosan from M. rouxii was 12.49%. Significant amounts (7.42-39.81%) of glucan were associated with chitinous compounds from both species and could not be eliminated by the extraction method used. The degrees of acetylation were determined to be 76.53 and 50.07% for chitin from A. niger and M. rouxii, respectively, and 19.5% for M. rouxii chitosan. The crystallinity of fungal chitin and chitosan was estimated to be less intense than in corresponding materials from shrimp shells. The extracted chitin and chitosan in a concentration of 0.1% reduced Salmonella Typhimurium DT104 2576 counts by 0.5-1.5 logs during a 4 day incubation in tryptic soy broth at 25 degrees C. Furthermore, all tested chitinous materials from fungal sources significantly reduced lesions caused by Botrytis cinerea and Penicillium expansum in harvested apples.

Chitosan as a Novel Edible Coating for Fresh Fruits

“…Due to the nontoxic and biocompatible properties of chitosan (Wu et al, 2005), it has been considered a candidate for substitution of fungicides in horticultural cultivation (Bautista-Banos et al, 2006). The main difference between the practical grade chitosan solutions and the commercial chitosan formulation arises from the techniques of their preparation.…”

Biomedical Activity of Chitin/Chitosan Based Materials—Influence of Physicochemical Properties Apart from Molecular Weight and Degree of N-Acetylation

“…Recently, more attention has been paid to the production of chitin and chitosan from fungal sources [61,62]. Wu et al [61], determined the yield (alkali-insoluble material, crude chitin, and the glucosamine content in crude materials) and physicochemical properties (DA, crystallinity) of chitin and chitosan isolated from Aspergillus niger and Mucor rouxii; they examined the bioactivity of fungal chitin and chitosan against the food-borne pathogen Salmonella Typhimurium and the plant pathogens Botrytis cinerea and Penicillium expansum. The biological properties of these samples were compared with those obtained for commercial chitosan obtained from crustacean shells.…”

Three-dimensional polymeric systems for cancer cell studies

“…Chitin, a structural and protective material, is found in the shells of crustacean and mollusks, in the backbone of squids, and the cuticle of insects, and is an important constituent of the exoskeleton (Baxter et al 1992). Chitin is also present in the algae commonly known as marine diatoms, in protozoa, and in the cell walls of several fungal species (Wu et al 2005). Chitin is one of the most abundant organic materials, second only to cellulose in the amount produced annually by biosynthesis.…”