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Mutagenesis and selection were applied to a strain of Penicillium echinulatum by treating conidia with hydrogen peroxide or 1,2,7,8-diepoxyoctane and then by incubating the conidia for 48 h in broth containing microcrystalline cellulose washed in 0.5% (w/v) aqueous 2-deoxyglucose before plating them onto cellulose agar containing 1.5% (w/v) glucose from which colonies showing the fastest production of halos of cellulose hydrolysis were selected. This process resulted in the isolation of two new cellulase-secreting P. echinulatum mutants: strain 9A02S1 showing increased cellulase secretion (2 IU ml-1, measured as filter paper activity) in submerged culture in agitated flasks containing a mineral salts medium and 1% of cellulose, and strain 9A02D1, which proved more suitable for the production of cellulases in semisolid bran culture where it produced 23 IU of beta-glucosidase per gram of wheat bran.

Aim:  To evaluate the solid‐state fermentation (SSF) production of cellulase and hemicellulases (xylanases), by Penicillium echinulatum 9A02S1, in experiments carried out with different concentrations of the pretreated sugar cane bagasse (PSCB) and wheat bran (WB). Methods and Results:  This study reports the production of xylanolytic and cellulolytic enzymes by P. echinulatum 9A02S1 using a cheap medium containing PSCB and WB under SSF. The highest amounts of filter paper activity (FPA) could be measured on mixtures of PSCB and WB (32·89 ± 1·90 U gdm−1). The highest β‐glucosidase activity was 58·95 ± 2·58 U gdm−1 on the fourth day. The highest activity for endoglucanases was 282·36 ± 1·23 U gdm−1 on the fourth day, and for xylanases the activity was around 10 U gdm−1 from the second to the fourth day. Conclusions:  The present work has established the potential of P. echinulatum for FPA, endoglucanase, β‐glucosidase and xylanase productions in SSF, indicating that WB may be partially substituted by PSCB. Significance and Impact of the Study:  The incorporation of cheap sources, such as sugar cane bagasse, into media for the production of lignocellulose enzymes should help decrease the production costs of enzymatic complexes that can hydrolyse lignocellulose residues for the formation of fermented syrups, thus contributing to the economic production of bioethanol.