High-yield production of a low-temperature-active polygalacturonase for papaya juice clarification
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- 作者：Tao Tu ; Kun Meng ; Yingguo Bai ; Pengjun Shi ; Huiying Luo ; Yaru Wang ; Peilong Yang ; Yuhong Zhang ; Wei Zhang ; Bin Yao
- 关键词：Achaetomium sp. Xz8 ; Endo-polygalacturonase ; Low-temperature-active ; High specific activity ; Juice clarification
- 刊名：Food Chemistry
- 出版年：2013
- 出版时间：1 December, 2013
- 年：2013
- 卷：141
- 期：3
- 页码：2974-2981
- 全文大小：1417 K
文摘
A novel endo-polygalacturonase (endo-PG I) from Achaetomium sp. Xz8 was identified, overexpressed in Pichia pastoris, and characterized in this report. Recombinant endo-PG I is distinguished from other enzyme counterparts by its high activity towards polygalacturonic acid (49,934 U/ml) and high yield in the 15-l fermentor (2.13 g/l). It exhibits optimal activity at 45 ¡ãC and remained active over a broad temperature range of 0-80 ¡ãC. Distinct from most fungal polygalacturonases that have acidic pH optima, endo-PG I is optimally active at pH 6, similar to the pH of fresh papaya juice (5.7). Endo-PG I alone reduced the viscosity of papaya juice by 17.6 % , and increased its transmittance by 59.1 % . When combined with a commercial pectin methylesterase, it showed much higher efficiency with a synergy degree of more than 1.25. All these favourable enzymatic properties make endo-PG I attractive for potential applications in the juice industry.