Improved production of polygalacturonate lyase by combining a pH and online methanol control strategy in a two-stage induction phase with a shift in the transition phase
Improved production of polygalacturonate lyase by combining a pH and online methanol control strategy in a two-stage induction phase with a shift in the transition phase
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DOI：
10.1007/s10295-009-0677-x
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发表时间：
2010-04
影响因子：
3.4
通讯作者：
M. S. Qureshi;Dongxu Zhang;G. Du;Jian Chen
中科院分区：
文献类型：
--
作者：
M. S. Qureshi;Dongxu Zhang;G. Du;Jian Chen
多聚半乳糖醛酸裂解酶是一种在纺织工业中大量应用的酶。在此之前，我们在毕赤酵母中重组了多聚半乳糖醛酸裂解酶基因，用于表达该酶。为了提高聚半乳糖醛酸裂解酶（PGL）的产量，将甲醇在线控制和两阶段pH控制策略相结合，提出了一种组合策略。对于生长阶段的两阶段pH控制策略，将pH控制在5.5，并且在诱导阶段，研究不同pH水平的最佳酶生产。在在线甲醇控制策略中，研究了不同甲醇水平（v/v）在pH 5.5下的最佳酶产量。将这两种策略结合在一起以提高PGL生产率，并且将诱导阶段分为两个阶段，其中甲醇浓度在线维持在不同水平。在诱导阶段引入过渡阶段，而不是在生长阶段之后引入过渡阶段。根据细胞的甲醇消耗量、最适pH值、细胞活力和P.帕斯托里斯。采用该策略，产量比常规条件提高了一倍，多聚半乳糖醛酸裂解酶活力最高可达1，631 U/ml。这种策略被证明是非常有用的，通过实现更高的细胞活力，醇氧化酶活性和磷酸盐相关化合物的细胞在诱导阶段的多聚半乳糖醛酸裂解酶的生产增强。
Polygalacturonate lyase is a kind of enzyme that is abundantly used in the textile industry for cotton scouring. Previously, we reconstructed the polygalacturonate lyase gene inPichia pastorisfor the expression of this enzyme. To enhance the production of polygalacturonate lyase (PGL), a combined strategy was formulated by combining online methanol control and two-stage pH control strategies. For the two-stage pH control strategy during the growth phase, the pH was controlled at 5.5, and in the induction phase different pH levels were investigated for the optimum enzyme production. During the online methanol control strategy, the different levels of methanol (v/v) were investigated for the best enzyme production at pH 5.5. These two strategies were combined together for enhanced PGL productivity, and the induction phase was divided into two stages in which methanol concentrations were maintained at different levels online. The transition phase was introduced during the induction phase instead of introducing it after the growth phase. The two-stage combination strategy was formulated on the bases of methanol consumption of cells, optimal pH, cell viability and the production of polygalacturonate lyase byP. pastoris. By using this strategy, the production was doubled compared with common conditions, and the highest polygalacturonate lyase activity reached 1,631 U/ml. This strategy proved to be very useful for the enhancement of polygalacturonate lyase production by achieving higher cell viability, alcohol oxidase activity and phosphate-related compounds of the cells during the induction phase.