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草酸青霉基因POX02968对纤维素酶和木聚糖酶产量调控分析

Analysis of the Regulation of Cellulase and Xylanase Production by the Gene POX02968 in Penicillium oxalicum

  • 摘要: 木质纤维素的有效水解是木质纤维素生物炼制的关键步骤。在生产中,降解木质纤维素所用的纤维素酶和木聚糖酶来自丝状真菌,但是酶产量很低。探究丝状真菌如何高产纤维素酶和木聚糖酶对用基因工程法提高丝状真菌纤维素酶和木聚糖酶的产量具有重要意义。本研究在草酸青霉(Penicillium oxalicum)中鉴定了一个调控纤维素酶和木聚糖酶产量的基因POX02968。在Avicel诱导条件下,和出发菌株ΔPoxKu70相比,缺失突变体ΔPOX02968的纤维素酶包括滤纸酶、对硝基苯基-β-D-纤维二糖苷酶、羧甲基纤维素酶和对硝基苯基-β-D-吡喃葡萄糖苷酶以及木聚糖酶的产量显著下降13.3%~48.7%。基因POX02968与菌株的生长和孢子形成有关。本研究还发现基因POX02968的缺失导致草酸青霉胞外蛋白减少。氨基酸序列比对分析表明POX02968包含1个CSN8_PSD8_EIF3K结构域,推测为翻译起始因子3亚基K。

     

    Abstract: Effective degradation of lignocellulose is a key step for lignocellulosic biorefining. Cellulases and xylanases used for lignocellulosic degradation in industry come from filamentous fungi, but fungal enzyme yields are quite low. Understanding how filamentous fungi highly produce cellulases and xylanases is of great significance to improve cellulase and xylanase yields via genetic engineering. In present work, we identified a gene POX02968 regulating cellulase and xylanase production in Penicillium oxalicum. The P. oxalicum mutant ΔPOX02968 decreased the production of cellulases(filter paper cellulase, p-nitrophenyl-β-cellobiosidase, carboxymethylcellulase and p-nitrophenyl-β-glucopyranosidase) and xylanases to various degrees compared with the parental strain ΔPoxKu70 when cultivated on Avicel, ranging from 13.3% to 48.7%. Additionally, the gene POX02968 was found to be involved in fungal growth and sporulation. Deletion of the gene POX02968 in P. oxalicum resulted in the reduction of extracellular proteins. Protein sequence alignment analysis indicated that POX02968 contained a CSN8_PSD8_EIF3 K domain, speculating that it encoded the translation initiation factor 3 subunit K.

     

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