Production and properties of the linamarase and amygdalase activities of Penicillium aurantiogriseum P35

The effects of medium composition on the production of beta-glucosidase (am ygdalase and linamarase) by Penicillium aurantiogriseum P35 were studied an d the medium optimized as follows (g/l of deionized water): pectin, 10.0; ( NH4)(2)SO4, 8.0; KH2PO4, 8.0; Na2HPO4, 2.8; MgSO4. 7H(2)O, 0.5; yeast extra ct, 4.0; initial pH 6.0. When grown in a bench fermenter on this medium, th e fungus produced 50.5 mU of amygdalase and 9.4 mU of linamarase per mi of culture broth. Two beta-glucosidases (PGI and PGII), each having amygdalase and linamarase activities, were recovered from the culture broth and purif ied; their relative molecular weights, as native enzymes, were estimated to be about 247000 and 147000, respectively. Both enzymes showed the same opt imum pH (6.0) but different optimum temperatures (55 and 60 degrees C for P GI and PGII, respectively). Thermostability (10 min at 60 degrees C) and ha lf-life of enzyme activity (7 hours at 60 degrees C) of PGII were higher th an those of PGI(10 min at 50 degrees C and 2 hours at 55 degrees C, respect ively). A wide range of cyanogenic glycosides (such as tetraphyllin B, epiv olkenin, gynocardin, passibiflorin, prunasin, taxiphyllin, amygdalin, lucum in, sambunigrin, dhurrin, linamarin and cardiospermin sulfate) were hydroly zed by both enzymes.