Beside their traditional food usage, mushrooms can be used as a source of many
pharmacologically active compounds, especially polysaccharides. Wastes after industrial
processing of edible mushrooms, such as Agaricus or Pleurotus species, can also become free
and alternative source of chitin – chitosan materials, beside the traditional industrial source –
shellfish waste materials.
Chitosan is an attractive material for multiple industrial applications, most of them in
nutritional, pharmacological, biomedicinal and cosmetic fields.
Chitosans have been extracted from Pleurotus ostreatus, Agaricus hortensis and
Lycoperdon perlatum using successive alkali and acidic extraction and characterized by
physiochemical methods, including 13C NMR and IR spectrometry.
Chitosan yields were usually within the range of 3 - 7% of the mushroom dry weight,
depending on stage of growth and mushroom parts, with great intra- and extra-species
variabilities, in agreement with literature. Exceptionally high chitosan yield, exceeding 40%
of the mushroom dry weight, were obtained from overripe Lycoperdon fruiting bodies
containing spores. The degree of acetylation (DA) of the isolated mushroom chitosans were in
the range form 0.18 to 0.5, molecular weights in the range from 10 to100 kDa, in accordance
with literature.
Harsh conditions with excessive amount of caustic alkalies and high temperatures
(120 - 130ºC) have been necessary for effective chitin deacetylation with sufficient chitosan
yields. This process is the cause of relative high chitosan prices and produces great amount of
alkali sewages. Development of ecological and cheap biotechnological process of extraction
chitosan from mushroom biomass without the treatament with excessive caustic alkalies is in
progress at present at time our department with promising results.