Recherche de nouvelles activités saccharifiantes thermostables chez les champignons filamenteux

We have searched for producers of a saccharifying activity with improved thermostability compared with industrial amyloglucosidases. These producers were chosen among thermophilic, thermotolerant, or even mesophilic fungi. Among the 846 isolated strains, five species (two Thermoascus spp., a member of the Aspergillus fumigatus group, and two members of the Aspergillus niger group) showed an amyloglucosidasic complex with the required property. Whereas the first three of these were thermophilic or thermotolerant strains, the latter two strengthen the idea that mesophilic strains can produce thermostable enzymes. The thermostability of the saccharifying complex of the Thermoascus spp., established with a half-life measure, was found to be far better than the other ones. The industrial use of these strains was discussed, and Thermoascus crustaceus seems to be the most advantageous one. Key words: filamentous fungi, amyloglucosidases, thermostability, Thermoascus.