Cellulase Hyper-Producing Fungus Penicillium janthinellum NCIM 1366 Elaborates a Wider Array of Proteins Involved in Transport and Secretion, Potentially Enabling a Diverse Substrate Range.

The efficient breakdown of lignocellulose requires the concerted activity of multiple enzymes. Previous studies on Penicillium janthinellum NCIM 1366 (PJ-1366) have revealed a more versatile repertoire of cellulases as compared to the hypercellulolytic strain Trichoderma reesei RUT-C30. Since a robust transport and secretion network is necessary to achieve proficient enzyme production, the transporters and extracellular proteins of PJ-1366 identified from its genome data were compared with those of Penicillium rolfsii (the phylogenetically closest species) and T. reesei RUT-C30 (the industrial work horse for cellulase production). Transmembrane proteins formed 20.4%, 21.0% and 18.2%, respectively of the proteome of PJ-1366, P. rolfsii and T. reesei RUT-C30, and 292 of them were mapped as transporters in PJ-1366. Major facilitator superfamily transporters (264) and sugar transporters (167) are abundant in PJ-1366, which probably aid in the uptake of oligosaccharide inducers of cellulase. The number of extracellular proteins (1007) in PJ-1366 is the highest reported for a Penicillium species. Also, PJ-1366 encoded 1.5 × more proteins involved in carbohydrate metabolism than the other fungi, and its secreted CAZymes belonged to much more diverse families (73), potentially enabling the fungus to act on heterogenous substrates. Structural differences in some untranslated protein response (UPR) effectors like Pdi and Clx detected in PJ-1366 may facilitate unique modes of cellulase regulation. [ABSTRACT FROM AUTHOR]