Improving selenium extraction by sequential enzymatic processes for Se-speciation of selenium-enriched Agaricus bisporus

Abstract.

Sample preparation methods based on the use of proteolytic and cell wall digesting enzymes for the speciation analysis of selenized mushroom were investigated. The sample (Agaricus bisporus; 160 µg total Se per g sample) was grown on compost supplemented with selenized yeast. Experiments were carried out to elucidate the possible role of the cell wall digesting enzymes – Lysing enzyme and Driselase – in the improvement of extraction efficiency with and without inhibiting proteolysis during cell wall digestion. A 3-step procedure applying Lysing enzyme and pronase gave the highest extraction efficiency (89%); however, the best species recovery was achieved by a one-step proteolytic procedure. All the procedures of selenium speciation were controlled by independent ICP-AES analysis measuring the total amount of selenium.