Biotechnology Bulletin ›› 2018, Vol. 34 ›› Issue (3): 200-207.doi: 10.13560/j.cnki.biotech.bull.1985.2017-0795

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Fusion of Phytase YiAPPA with the Raw-starch Binding Domain and Characterization of the Fusion Enzyme

YUAN Lin, HUANG Zhao, ZENG Jing, GUO Jian-jun, ZHANG Ting, Lü Jun   

  1. Institute of Microbiology,Jiangxi Academy of Sciences,Nanchang 330096
  • Received:2017-09-21 Online:2018-03-20 Published:2018-04-10

Abstract: This work aims to obtain a fusion enzyme with improved enzymatic properties comprised of phytase YiAPPA and raw-starch binding domain SBD. The raw-starch binding domain(SBD)of thermoacidophilic α-amylase GTamy was introduced into the C-terminal end of Yersinia intermedia phytase(YiAPPA)to generate a fusion enzyme YiAPPA-SBD. The fusion of YiAPPA with SBD resulted in improvements both in terms of thermal activity and stability. Besides,YiAPPA-SBD could absorb raw corn starch. Specifically,YiAPPA-SBD exhibited higher relative activity than YiAPPA within 55-90℃.The half-life of YiAPPA-SBD increased from 15 min to 30 min when incubated at 80℃. The adsorption efficiency of YiAPPA-SBD was 80% when the raw corn starch concentration was over 8%. Moreover,YiAPPA-SBD showed minor changes in its specific activity(3 900 U/mg)at optimal pH(pH 4.5),indicating that YiAPPA-SBD has solid pH stability and resistance to protease when compared to YiAPPA.

Key words: phytase YiAPPA, raw-starch binding domain, fusion enzyme, thermostability, raw-starch adsorption efficiency