Increased Heterologous Protein Production in Aspergillus niger Fermentation through Extracellular Proteases Inhibition by Pelleted Growth

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• 作者：Jianfeng Xu ; Liping Wang ; Darin Ridgway ; Tingyue Gu ; and Murray Moo-Young
• 刊名：Biotechnology Progress
• 出版年：2000
• 出版时间：April 2000
• 年：2000
• 卷：16
• 期：2
• 页码：222 - 227
• 全文大小：79K
• 年卷期：v.16,no.2(April 2000)
• ISSN：1520-6033

文摘

The dependence of filamentous fungal protease secretion on morphology was investigated by employing the recombinant Aspergillus niger strain AB4.1[pgpdAGLAGFP]which contains a gene for the glucoamylase-GFP (green fluorescence protein) fusionprotein. Different inoculum levels were used to obtain different sizes of pellet or freemycelia. The extracellular protease activity of the cultures varied with the pellet sizeand decreased dramatically when the morphology was changed from free mycelia topellets. The culture with an optimal pellet size of 1.6 mm was obtained from aninoculum of 4 × 10⁶ spores/mL. It resulted in a specific protease activity of 158 units/L, only one-third of that in free mycelial growth, and a maximum specific GFP yieldof 0.98 mg/g (cell mass) compared to 0.29 mg/g for free mycelial growth with aninoculum of 10⁷ spores/mL. The results indicate that this bioprocessing strategy canbe effectively used to inhibit protease activity in filamentous fungal fermentation andthereby to enhance heterologous protein production.