Hypocrea jecorina (anamorph Trichoderma reesei) is a fungus of noteworthy industrial importance, mainly because of its employment in both fermentative production of native extracellular enzymes and heterologous protein production. Hydrolases secreted by this fungus have achieved broad areas of applications, e.g., in pulp and paper (4, 35, 50), food and feed (9, 27, 49), and textile (23,26,36) industries. The set of hydrolytic enzymes produced by H. jecorina comprises two main cellobiohydrolases, CBHI and CBHII (EC 3.2.1.91) (43); endo-␤-1,4-glucanases EGI to EGV (EC 3.2

The filamentous fungi Aspergillus niger and

Two major xylanases (XYN I and XYN II) of the filamentous fungus

No abstract

This study reports the vital regulatory influence of Xyr1 (xylanase regulator 1) on the transcription of hydrolytic enzyme-encoding genes and hydrolase formation on lactose in Hypocrea jecorina. While the transcription of the xyr1 gene itself is achieved by release of carbon catabolite repression, the transcript formation of xyn1 (xylanase 1) is regulated by an additional induction mechanism mediated by lactose. Xyr1 has an important impact on lactose metabolism by directly activating xyl1 (xylose reductase 1) transcription and indirectly influencing transcription of bga1 (b-galactosidase 1). The latter is achieved by regulating the conversion of D D-galactose to the inducing carbon source galactitol.