斜卧青霉去泛素化蛋白酶CREB的缺失提高纤维素酶的生产

Enhanced cellulase production of Penicillium decumbens by knocking out CreB encoding a deubiquitination enzyme

斜卧青霉Penicillium decumbens T.是1种重要的产纤维素酶丝状真菌,能有效地降解利用木质纤维素生产第2代生物燃料。为了提高斜卧青霉纤维素酶的产量,构建了去泛素化酶基因creB的敲除盒,并通过同源双交换重组的方法,获得了creB基因缺失突变株ΔcreB。该突变株呈现明显的纤维素酶表达分泌抗葡萄糖代谢阻遏效应,ΔcreB菌株的滤纸酶活、内切纤维素酶活、木聚糖酶活以及外切纤维素酶活分别提高1.8倍、1.71倍、2.06倍以及2.04倍,其胞外蛋白质含量提高了2.68倍。确定了creB基因缺失突变株具有抗碳源代谢物阻遏的生理现象,CREB对斜卧青霉生产纤维素酶的能力具有显著影响,为系统改造丝状真菌高产纤维素酶菌株提供了理论指导。

Penicillium decumbens T.is an important filamentous fungus for the production of cellulases to effectively degrade lignocellulose for second generation biofuel production.In order to enhance the capability of Penicillium decumbens to produce cellulases,we constructed a creB（a deubiquitinating enzyme encoding gene） deletion cassette,and generated a creB knockout strain with homologous double crossover recombination.This mutation resulted in a detectable decrease of carbon catabolite repression（CCR） effect.The filter paper activity,endoglucanase activity,xylanase activity and exoglucanase activity of the ΔcreB strain increased by 1.8,1.71,2.06 and 2.04 fold,respectively,when comparing with the parent strain Ku-39.A 2.68 fold increase of extracellular protein concentration was also observed.These results suggest that the deletion of creB results in CCR derepression.These data also suggest that CREB influences cellulase production of Penicillium decumbens.In generation,this study provides information that can be helpful for constructing cellulase hyper-producing strain.