Simultaneous manipulation of transcriptional regulator CxrC and translational elongation factor eEF1A enhances the production of plant-biomass-degrading enzymes of Penicillium oxalicum.

Genetic engineering is an efficient approach to improve fungal bioproducts, but the specific targets are limited. In this study, it was found that the key transcription repressor CxrC of Penicillium oxalicum could physically interact with the translational elongation factor eEF1A that positively regulated the production of plant-biomass-degrading enzymes by the fungus under Avicel induction. Simultaneously deletion of the cxrC and overexpression of the eEF1A in the strain Δku70 resulted in 55.4%-314.6% higher production of cellulase, xylanase and raw-starch-degrading enzymes than that of the start strain Δku70. Transcript abundance of the genes encoding predominant cellulases, xylanases and raw-starch-degrading enzymes were significantly upregulated in the mutant ΔcxrC::eEF1A. The ΔcxrC::eEF1A enhanced saccharification efficiency of raw cassava flour by 9.3%-15.5% at early-middle stage of hydrolysis in comparison with Δku70. The obtained knowledges expanded the sources used as effective targets for increased production of plant-biomass-degrading enzymes by fungi.