Development Of A Reusable Selective Marker System In Penicillium Decumbens

Penicillium decumbens is an important cellulase productive filamentous fungi, which can effectively utilize lignocellulose to produce monosaccharide or oligosaccharide for the second generation biofuel. Currently, the ability of cellulase production by filamentous fungi can not meet current industrial production needs. Genetic engineering technologies can manufacture and modify industrial strains of Penicillium decumbens that have quantifiable economic and ecological benefits. Modification of the such industrial strains use a large number of selective markers, but currently selective markers for Penicillium decumbens were still low in number. In order to improve this situation we have developed a reusable selective marker system for accumulated modification with in Penicillium decumbens industrial strains.CreB and CreC are importmant deubiquitinating enzymes of filamentous fungi in the conditions of carbon catabolite repression. In order to syudy the influences of both CreB and CreC, we constructed a creB deletion cassette and a creC deletion cassette. When constructing the deletion cassettes, we added homologous sequence to both two sides of pyrG expression cassette. We generated strains AcreB and AcreC with homologous double crossover recombination. Calculated AcreB and AcreC on the medium containing5'-FOA, we could screen strains that had self-splicing of pyrG. These strains provided the foundations for developing a reusable selective marker system of Penicillium decumben.Strains AcreB and AcreC had derepression condation in complex medium containing cellulose and glucose. We found the filter paper activity, endoglucanase activity, xylanase activity and exoglucanase activity of AcreB was increasd by1.8times,1.71times,2.06times and2.04times compared to the parent strain Ku-39; extracellular protein concentration we found to be improved by2.68times also. The filter paper activity, endoglucanase activity, xylanase activity and exoglucanase activity of AcreC was also found to have been increasd by1.55times,1.16times,1.4times and1.25times comparing with the parent strain Ku-39; extracellular protein concentration is improved by2.5times.