High level expression of secretory phytases in Pichia pastoris
Refereed conference paper presented and published in conference proceedings

香港中文大學研究人員

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摘要Introduction: Phytases catalyze the release of inorganic phosphate (Pi) from phytate, a major storage compound of phosphorus in plant seeds. However, non-ruminant animals, including human, swine and poultry, could not digest phytate as they have little phytase activity in their guts. Discharge of undigested phytate into environment may cause phosphorus pollution. Phytate is also considered as an "anti-nutrient" for reducing dietary absorption of essential minerals as it can form insoluble and stable complexes with metal ions such as zinc, iron, magnesium and calcium. It is, therefore, necessary to develop sustainable approaches for environmentally-friendly utilization of this valuable and abundant natural resource. To this end, our team would like to employ yeast as a tiny factory to produce high level expression of secretory phytases for phytate hydrolysis.

Objective: To construct a platform for high-level expression of secretory phytases in Pichia pastoris.

Materials and methods: Pichia pastoris GS115 was used to express bacterial phytases. Four thermostable phytases from Yersinia frederiksenii, Bacillus sp. MD2, B. subtilis, and Aspergillus niger were selected. Four phytases genes were synthesized after codon optimization and cloned into pPICZαA vector in which the original AOX1 promoter was replaced by inducible PHO89 promoter. Finally, the plasmids were transformed into P. pastoris GS115 for protein expression.

Results: The four phytases were successfully expressed in P. pastoris (YF, 50kDa, 0.23U/mL; phyA, 51kDa, 0.34U/mL; MD2, 60kDa with glycosylation, 0.14U/mL; phyUS417, 0.15U/mL). YF and phyA phytases have similar pH-activity profile range from pH 1.5 to pH 6.5 at 37°C.

Conclusion: We have constructed an array of Pichia pastoris strains that express bacterial phytases at high level. Optimization of these strains using fermentation strategies is in progress.
出版社接受日期26.08.2018
著者Zhen Ming Xie, Hei Tsing Cheryl Yeung, Wing Ping Fong, Wai Kei Paul Tsang
會議名稱9th INTERNATIONAL CONGRESS ON BIOCATALYSIS
會議開始日26.08.2018
會議完結日30.08.2018
會議地點Hamburg University of Technology
會議國家/地區德國
會議論文集題名9th INTERNATIONAL CONGRESS ON BIOCATALYSIS ABSTRACTS
出版年份2018
月份8
出版社Hamburg University of Technology
出版地Germany
頁次64 - 64
語言英式英語
關鍵詞Pichia pastoris, phytase

上次更新時間 2019-12-02 於 14:39