ABSTRACT
Chitosan was originally identi…ed by Kreger (1954) in Phycomyces blakesleeanus, and it was considered a characteristic component of the cell wall from Mucoromycotina (Zygomycota), being in higher concentrations than chitin in species of this group of fungi. However, further studies have proved that chitosan is also present in Ascomycota and Basidiomycota species. In fact, the evidence of the presence of genes encoding chitin deacetylases (which are involved in chitosan biosynthesis as described below) in almost all fungi, suggests that chitosan is a universal component of the cell wall of fungi. In Ascomycota, chitosan was originally detected in the ascospores of Saccharomyces cerevisiae (Briza et al. 1988), but not in its vegetative walls, nor in the vegetative walls of Candida albicans (Banks et al. 2005). Chitosan was also found to be a component of the wall in Schizosaccharomyces pombe ascospores (Matsuo 2005), and of its vegetative cells, although in lesser amounts (Sietsma and Wessels 1990). Its presence was also reported in the mycelium of Aspergillus niger (Pochanavanich and Suntornsuk 2002). In Basidiomycota, it has been described to be present in Lentinus edodes and Pleurotus sajo-caju (Crestini, Kovac, and Giovannozzi-Sermanni 1996; Pochanavanich and Suntornsuk 2002). Noticeable was the description that the cell walls of the vegetative form of Cryptococcus neoformans contained higher amounts of chitosan than chitin (Banks et al 2005).
