草酸青霉BZH-2002产果胶酶特性研究

对草酸青霉菌（Penixillium oxalicum）BZH-2002菌株固体发酵果胶酶的特性及浸提条件进行了研究,确定其最佳产酶时期为72—92h,利用干物质量最快的时期为24—72h发酵产酶期间培养基介质中pH值呈“V”字形变化。该菌株以甜菜渣、葵花盘为碳源,以（NH）2SO4为氮源时产酶率最高,分别高达4．33万和4．56万U／g干物质,（NH4）2SO4最佳用量0．9g/10g甜菜渣。此外,浸提方法对果胶酶产率也有一定影响,1％NaCl作为浸提液的效果最好,最佳浸提时间1h,浸提温度25—40℃。     

草酸青霉BZH-2002果胶酶固体发酵条件研究

对草酸青霉菌(Penixillium oxalicum)BZH-2002菌株固体发酵果胶酶的主要影响因子温度、初始pH值、含水量及接种量进行了实验探讨,确定了最佳培养条件：温度为30℃,初始pH值为4．8,固体培养基含水量控制在30～35ml/10g甜菜渣,接种量3～4%。同时对该菌株固体发酵提取液中果胶酶的酶学特性进行了初步研究,结果表明,该酶最适反应温度和pH分别为55℃和pH4．8,在40℃温度下和pH3．5～5．5范围内,酶活性较稳定。     

农杆菌介导海洋草酸青霉转化体系及聚酮合酶Pks生物学功能*

为研究南海柳珊瑚共附生草酸青霉SCSGAF0023的聚酮合酶(PKS)生物学功能,采用农杆菌介导法构建草酸青霉SCSGAF0023的Pks敲除株ΔPks,比较野生菌株及ΔPks的生长发育及环境适应性差异。以草酸青霉SCSGAF0023分生孢子为受体,p0380-hygB为双元载体,成功实现草酸青霉SCSGAF0023的遗传转化。结果表明:农杆菌浓度为OD₆₀₀=0.5,在200μmol/L 乙酰丁香酮(AS)诱导下与10⁷个/ml草酸青霉SCSGAF0023孢子于25℃共孵育时转化效率最高。基于上述转化体系,成功获得Pks敲除株ΔPks,并首次证实Pks正向调控草酸青霉SCSGAF0023产孢,但不影响其对环境的适应性。这为进一步系统研究真菌PKSs及聚酮化合物对真菌生长发育与环境适应性的影响提供素材。     

草酸青霉YTY及其突变体解磷能力、pH和分泌有机酸的关系

本研究利用离子束-UV复合诱变草酸青霉YTY选育高效解磷突变体,分析了出发菌株YTY及其突变体解磷过程中的解磷能力、pH和有机酸的变化及其相关性,探讨草酸青霉的解磷机理.结果 表明:离子束-UV复合诱变选育获得5株高效解磷突变株P9-8、P9-9、P15-4、P15-6和P15-7,解磷能力均较YTY提高60％以上.解...     

Purification and characterization of two novel β-glucosidases from Penicillium oxalicum and their application in bioactive ginsenoside production

Abstract

The fungus Penicillium oxalicum is able to selectively metabolize the 20(S)-protopanaxadiol ginsenosides Rb1, Rb2 and Rc to the bioactive ginsenoside compound K using extracellular glycosidases. In this study, two novel extracellular ginsenoside-hydrolyzing enzymes GH3-1 and GH3-2 were purified and characterized from P. oxalicum culture. Using ginsenosides as substrates, GH3-1 and GH3-2 synergistically catalyzed the hydrolysis of Rb1, Rb2 and Rc to yield the final product Compound K (C-K). The hydrolysis pathways were determined to be: Rb1→Rd→F2→C-K, Rb2→CO→CY→C-K and Rc→Mb→Mc→C-K for GH3-1 and GH3-2, respectively. The two enzymes differ, especially in composition, molecular weight, stability and substrate specificity, from GH1, a glycosidase previously purified from the same fungus. These enzymes could be of interest in glycoside degradation, especially in the production of minor ginsenosides.     

草酸青霉对含钾矿物风化及钾溶出的影响

【目的】探讨含钾硅酸盐矿物在草酸青霉(Penicillium oxalicum)作用下的风化及钾溶出情况。【方法】利用等离子体发射光谱、X-射线能谱、X-射线光电子能谱分析了3种常见含钾硅酸盐矿物(钾长石、白云母和黑云母)在草酸青霉作用后浸出液和矿物表面元素含量的变化;通过X-射线衍射分析矿物晶相结构的变化;采用共聚焦激光扫描显微镜表征了草酸青霉在矿物表面形成的生物膜;测量了培养液中不同碳源与氮源组分对草酸青霉解钾的影响。【结果】草酸青霉对结构稳定的钾长石和白云母风化速率较低,相比而言黑云母容易被风化并释放可溶性钾元素;草酸青霉在矿物表面形成了网状结构的生物膜,有利于微环境的生成及有机酸在其内的富集,促进微环境内钾的释放,强化微生物对矿物的风化作用;草酸青霉对多种碳源及氮源都表现出较好的适用性。【结论】草酸青霉是一种能够促进多种含钾矿物风化和钾溶出的真菌,在堆肥和生物肥料领域具有广泛的应用前景。     

绿色荧光蛋白和潮霉素抗性双标记载体转化草酸青霉菌P8的研究

草酸青霉菌P8(Penicillium oxalicum)溶磷菌株具有较强的溶解多种无机难溶磷的能力和促进作物生长的作用。为研究P8在作物根际的定殖状况,用携带加强型绿色荧光蛋白和潮霉素抗性的双标记载体转化溶磷青霉菌P8的原生质体,筛选出稳定、高效表达GFP并对潮霉素产生抗性的转化菌株,Southern杂交分析结果显示,外源质粒DNA是以非同源重组方式整合到转化菌株基因组染色体上。试验证明转化菌株的形态学特征和溶磷能力与野生型菌株无明显差别。     

Newly isolated Penicillium oxalicum A592-4B secretes enzymes that degrade milled rice straw with high efficiency

An enzyme producing micro-organism, which can directly saccharify rice straw that has only been crushed without undergoing the current acid or alkaline pretreatment, was found. From the homology with the ITS, 28S rDNA sequence, the strain named A592-4B was identified as Penicillium oxalicum. Activities of the A592-4B enzymes and commercial enzyme preparations were compared by Novozymes Cellic CTec2 and Genencore GC220. In the present experimental condition, activity of A592-4B enzymes was 2.6 times higher than that of CTec2 for degrading milled rice straw. Furthermore, even when a quarter amount of A592-4B enzyme was applied to the rice straw, the conversion rate was still higher than that by CTec2. By utilizing A592-4B enzymes, improved lignocellulose degradation yields can be achieved without pre-treatment of the substrates; thus, contributing to cost reduction as well as reducing environmental burden.