Tomomi Takeno

Characteristics of a cheese-like food produced by fermentation of the mushroom Schizophyllum commune

Lactate bacteria of the Lactobacillus and Streptococcus genera are normally employed in cheese making because these microbes have potent ability to produce lactate dehydrogenase. A milk-clotting enzyme is also necessary to make cheese. Recently, we discovered that some mushroom genera produce both lactate dehydrogenase and a milk-clotting enzyme. Using the mushroom Schizophyllum commune in place of a lactate bacterium, we produced a cheese-like food that contained about 0.58% beta-D-glucan, which has been shown to have preventive effects against cancer. The food also exhibited thrombosis prevention activity, prolonging the thrombin clotting time to 49.6-fold that of the control.

Development of mushrooms for thrombosis prevention by protoplast fusion

With thrombosis a major cause of death in Japan and the Western world, thrombin-inhibitory agents that constrain the formation of fibrin are sought. We screened for basidiomycetes showing anti-thrombin activity and isolated Laetiporus sulphureus. However, it was difficult to cultivate and its form was not satisfactory. We therefore used protoplast fusion between L. sulphureus and the commonly cultivated basidiomycete Hypsizygus marmoreaus to obtain cultivable basidiomycetes that produced an anti-thrombin substance. For the protoplast fusion of L. sulphureus and H. marmoreaus, the protoplast concentration, alternating electric field intensity, dielectrophoresis duration, and field pulse intensity used were of 1 x 10(7) protoplasts/ml, 100 V/cm.1 MHz, 60 s, and 8 kV/cm, respectively. The number of regenerated colonies obtained was 4961, from which 43 strains were selected for electrophoretic analysis. Four of the fusants were found to have a band from each parent in isozyme patterns obtained using their crude extract. The fruiting bodies of the fusants were very similar to those of H. marmoreaus. Crude extract from each of the fusants and from L. sulphureus showed anti-coagulative activity in terms of the thrombin clotting time. We thus obtained improved basidiomycetes that produce an anti-thrombin substance, are easily cultivated, and whose form resembles H. marmoreaus, a commonly used culinary mushroom.