Production of cello-oligosaccharides from corncob residue by degradation-synthesis reactions.

The cellulose-rich corncob residue (CCR) is an abundant and renewable agricultural biomass that has been under-exploited. In this study, two strategies were compared for their ability to transform CCR into cello-oligosaccharides (COS). The first strategy employed the use of endo-glucanases.

Simultaneous manipulation of multiple genes within a same regulatory stage for iterative evolution of Trichoderma reesei.

Background: While there is growing interest in developing non-canonical filamentous fungi as hosts for producing secretory proteins, genetic engineering of filamentous fungi for improved expression often relies heavily on the understanding of regulatory mechanisms.

Results: In this study, using the cellulase-producing filamentous fungus Trichoderma reesei as a model system, we designed a semi-rational strategy by arbitrarily dividing the regulation of cellulase production into three main stages-transcription, secretion, and cell metabolism. Selected regulatory or functional genes that had been experimentally verified or predicted to enhance cellulase production were overexpressed using strong inducible or constitutive promoters, while those that would inhibit cellulase production were repressed via RNAi-mediated gene silencing.