RESUMEN
AIMS: Elucidation of different physico-chemical parameters and the secretory enzymes released by Talaromyces verruculosus SGMNPf3 during cellulosic biomass degradation. METHODS AND RESULTS: We determined the optimal pH, temperature and time course parameters for the efficient degradation of different natural and commercial cellulosic substrates by T. verruculosus SGMNPf3, previously isolated from a forest soil. The optimal growth of the fungus and production of its cellulases were obtained when the culture condition was maintained at pH 3·3 and temperature 30°C. Activity of the crude cellulases was maximum at 60°C. Activity of cellulase enzymes produced on natural cellulose substrates was higher than that on commercial cellulose substrates. A continuous increase in cellulase activity at different time points indicated no apparent end product inhibition. This might be attributed to the high individual cellulases, notably ß-glucosidase (316·1 µmol g(-1) ) production. Zymogram of extracellular crude proteins showed two dominant extracellular protein bands of molecular weight 72·3 and 61·4 kDa, indicating their cellulolytic nature. MALDI-TOF and LC-MS/MS analysis of the 2DE spots also identified several enzymes including ß-glucosidase involved in the process of cellulose degradation. CONCLUSIONS: Based on its optimal parameters for cellulolytic activities, we suggest that the fungus is acido-mesophilic. There was apparently no end-product inhibition of the cellulase activity and this is attributed to the ability of the fungus to produce sufficient ß-glucosidase. The dominant proteins secreted by the fungus were confirmed to be cellulases. SIGNIFICANCE AND IMPACT OF THE STUDY: The high individual cellulase activities, better cellulase production on natural substrates and apparent absence of end-product inhibition are characteristics of T. verruculosus SGMNPf3 for use in harvesting naturally endowed energy in cellulosic biomass.