USE OF A NEW MEMBRANE-REACTOR SACCHARIFICATION ASSAY TO EVALUATE THE PERFORMANCE OF CELLULASES UNDER SIMULATED SSF CONDITIONS - EFFECT ON ENZYME QUALITY OF GROWING TRICHODERMA-REESEI IN THE PRESENCE OF TARGETED LIGNOCELLULOSIC SUBSTRATE

A new saccharification assay has been devised; in which a continuously buffer-swept membrane reactor is used to remove the solubilized sacch arification products, thus allowing high extents of substrate conversi on without significant inhibitory effects from the buildup of either c ellobiose or glucose. This diafiltration saccharification assay (DSA) can, therefore, be used to obtain direct measurements of the performan ce of combinations of cellulase and substrate under simulated SSF cond itions, without the saccharification results being complicated by fact ors that may influence the subsequent fermentation step. This assay ha s been used to compare the effectiveness of commercial and special in- house produced Trichoderma reesei cellulase preparations in the saccha rification of a standardized microcrystalline (Sigmacell) substrate an d a dilute-acid pretreated lignocellulosic substrate. Initial results strongly suggest that enzyme preparations produced in the presence of the targeted lignocellulosic substrate will saccharify that substrate more effectively. These results call into question the widespread use of the ''filter paper assay'' as a reliable predictor of enzyme perfor mance in the extensive hydrolysis of substrates that are quite differe nt from filter paper in both physical properties and chemical composit ion.