title: Efficient production of mutant phytase (phyA-7) derived from Selenomonas ruminantium using recombinant Escherichia coli in pilot scale.
abstract: A mutant gene of rumen phytase (phyA-7) was cloned into pET23b(+) vector and expressed in the Escherichia coli BL21 under the control of the T7 promoter. The study of fermentation conditions includes the temperature impacts of mutant phytase expression, the effect of carbon supplements over induction stage, the inferences of acetic acid accumulation upon enzyme expression and the comparison of one-stage and two-stage operations in batch mode. The maximum value of phytase activity was reached 107.0 U mL(-1) at induction temperature of 30°C. Yeast extract supplement demonstrated a significant increase on both protein concentration and phytase activity. The acetic acid (2 g L(-1)) presented in the modified synthetic medium demonstrated a significant decrease on expressed phytase activity. A two-stage batch operation enhanced the level of phytase activity from 306 to 1204 U mL(-1) in the 20 L of fermentation scale. An overall 3.7-fold improvement in phytase yield (35,375.72-1,31,617.50 U g(-1) DCW) was achieved in the two-stage operation.
authors.affiliation: Biorefinery & Bioprocess Engineering Laboratory, Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan; The Agricultural Biotechnology Research Center (ABRC), Academia Sinica, Taipei, Taiwan. Electronic address: lanchiwei@saturn.yzu.edu.tw.
authors.forename: John
authors.initials: J
authors.lastname: Chi-Wei Lan
authors.affiliation: Biorefinery & Bioprocess Engineering Laboratory, Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan.
authors.forename: Chih-Kai
authors.initials: CK
authors.lastname: Chang
authors.affiliation: Biorefinery & Bioprocess Engineering Laboratory, Department of Chemical Engineering and Materials Science, Yuan Ze University, Taoyuan, Taiwan.
authors.forename: Ho-Shing
authors.initials: HS
authors.lastname: Wu
mesh_terms: D010832:6-Phytase / Q000235:genetics / Q000378:metabolism*; D019342:Acetic Acid / Q000378:metabolism* / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D045424:Complex Mixtures / Q000378:metabolism; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D005285:Fermentation; D015870:Gene Expression; D010865:Pilot Projects; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D020357:Selenomonas / Q000737:chemistry* / Q000201:enzymology
chemical_list: D001426:Bacterial Proteins; D045424:Complex Mixtures; D011994:Recombinant Proteins; D010832:6-Phytase; D019342:Acetic Acid
keywords: Fermentation; Phytase; Phytic acid; Recombinant Escherichia coli; Specific activity