Agitation effects on morphology and protein productive fractions of filamentous and pelleted growth forms of recombinant Aspergillus niger
Agitation effects on morphology and protein productive fractions of filamentous and pelleted growth forms of recombinant Aspergillus niger
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DOI：
10.1016/j.procbio.2006.05.024
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发表时间：
2006-10-01
影响因子：
4.4
通讯作者：
Rinas, Ursula
中科院分区：
文献类型：
--
作者：
El-Enshasy, Hesham;Kleine, Joachim;Rinas, Ursula
使用组成型gpdA启动子和用于分泌的葡糖淀粉酶信号序列进行基因工程化以产生葡糖氧化酶的重组尼日尔在分批培养物中生长，搅拌速度为200-800 rpm，覆盖0.1-5 W kg（-1）的工业相关功率输入范围。的生长形态范围从大颗粒的平均直径为1500 μ m，在低功率输入到micropeilets嵌入在高功率输入的丝状网络。搅拌强度与生长形态和葡萄糖氧化酶生产的相关性显示，随着生长形态从颗粒状到丝状生长形式的变化，蛋白质生产能力增加。然而，随着功率输入的增加，暴露于较高的剪切应力也导致较低的生物质产率以及增加的多元醇（木糖醇）的瞬时形成和较高的草酸最终浓度。最高的比生产率被发现在年轻的丝状生长形式在高功率输入。虽然中等搅拌强度导致小颗粒在长时间培养过程中变得更有利。吖啶橙子染色程序区分真菌生物质的RNA富集区（红色）和RNA贫乏区（绿色），证明活性蛋白质生产限于丝状生长形式和真菌颗粒的外层。显示了通过图像分析确定的生物质的富含RNA的部分与生产率之间的相关性。(c)2006爱思唯尔有限公司保留所有权利。
Recombinant Aspergillus niger genetically engineered to produce glucose oxidase using the constitutive gpdA promoter and the glucoamylase signal sequence for secretion was grown in batch cultures at agitation speeds of 200-800 rpm covering the industrial relevant power input range of 0.1-5 W kg(-1). The growth morphology ranged from large pellets with an average diameter of 1500 mu m at low power input up to micropeilets embedded in a filamentous network at high power input. A correlation of agitation intensity with growth morphology and glucose oxidase production revealed an increase of the protein production capability with the change of the growth morphology from pelleted to filamentous growth forms. However, the exposure to higher shear stress with increasing power input also resulted in lower biomass yields as well as increased transient formation of polyol (xylitol) and higher final concentrations of oxalic acid. The highest specific production rates were found in young filamentous growth forms at high power input. Although intermediate agitation intensity leading to small pellets became more favorable during prolonged cultivation. An acridine orange staining procedure discriminating between RNA rich (red) and RNA poor regions (green) of the fungal biomass proved that active protein production is restricted to filamentous growth forms and the outer layer of fungal pellets. A correlation between the RNA rich fraction of the biomass determined by image analysis and the productivity is shown. (c) 2006 Elsevier Ltd. All rights reserved.