Suchergebnisse

The tacA gene, encoding the TacA repressor protein, was cloned by "walking the uncloned DNA" method from the genomic DNA of the fungus Penicillium verruculosum B1-221-151. Knockout of the tacA and niaD genes by the CRIS-PR/CAS9 led to the production of a new host strain P. verruculosum ΔniaDΔtacA, characterized by a higher rate of extracellular protein biosynthesis. Analysis of the transcription and expression of the cbhI gene in the original P. verruculosum B1-221-151 strain and in the P. verruculosum ΔniaDΔtacA strain showed a sharp increase in the level of cbhI gene transcription 2 h after the start of induction with cellobiose, cellotriose, gentiobiose, and a mixture of di- and trisaccharides in comparison with the transcription of the cbhI gene in the original strain. The speci c activity of cellobiohydrolase I, the main enzyme of the cellulolytic complex of the fungus P. verruculosum, by 96 h of fermentation of the ΔtacA strain increased 3 times compared to the original strain.

New recombinant strains of Penicillium verruculosum have been created with a high level of expression of homologous endo-β-1,4-glucanase II and heterologous phytase A A. niger, as well as heterologous endo-1,4-β-xylanase E P. canescens and phytase A A. niger, allowing to obtain highly active feed enzyme preparations (AF) capable of simultaneously signi cantly reducing viscosity non-starch polysaccharides, as well as increase the bioavailability of phosphorus and minerals of grain-based feed and, thus, increase the digestibility of nutrients of agricultural animal and poultry feed. Speci c AF activities for speci c substrates (xylanau, β-glucan, phytate) were studied, the qualitative and quantitative component composition of new AF was determined. On the basis of a new enzyme preparation containing homologous endo-β-1,4-glucanase II and heterologous phytase A A. niger, a recipient strain ∆nia D - was obtained, into which heterologous endo-1,4-β-xylanase E P. canescens was successfully cloned and, thus, a promising producer of three target enzymes was obtained simultaneously.