Transfer of a benomyl resistance marker by heat-inactivated Trichoderma reesei protoplasts

Production of alkaline cellulase by fungi isolated from an undisturbed rain forest of peru

Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an apparent decrease of them indicating that they are true alkaline cellulase producers. Aspergillus sp. LM-HP32, Penicillium sp. LM-HP33, and Penicillium sp. LM-HP37 were the best producers of FP cellulase (>3 U mL⁻¹) with higher specific productivities (>30 U g⁻¹ h⁻¹). Three strains have been found suitable for developing processes for alkaline cellulase production. Soils from Amazonian rain forests are good sources of industrial fungi with particular characteristics. The results of the present study are of commercial and biological interest. Alkaline cellulases may be used in the polishing and washing of denim processing of the textile industry.

Use of 2-deoxyglucose in liquid media for the selection of mutant strains of Penicillium echinulatum producing increased cellulase and β-glucosidase activities

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.