The potential of Humicola grisea var. thermoidea for bioconversion of sugar cane bagasse

Industrial and agricultural wastes, such as crop-shells and sugar cane bagasse (SCB) are abundant in Brazil. We have focused this work on the evaluation of the use of these lignocellulosic materials as substrates for growth and bioconversion by the thermophilic fungus Humicola grisea var. thermoidea. We have characterized, at molecular level, the protein production, cellulase activities and cellobiohydrolase (cbh1.1) gene transcription induced by SCB. The cellulolytic system of this fungus is early induced by SCB and a high FPase activity (up to 8U/ml after 72 h of incubation) was detected in supernatants from mycelial cultures. The Western-blot analysis showed the induction of cellulases in SCB cultures, while the Northern-blot detected the expression of cbh1 genes only in the presence of an inducer (SCB). Our results suggest that H. grisea var. thermoidea is a suitable microorganism for bioconversion of SCB to soluble carbon source and show that this fungus displays a complex of secreted proteins. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.