تولید آنزیم فیتاز بوسیله پروبیوتیک …

Production of Phytase Enzyme by a Bioengineered Probiotic
for Degrading of Phytate Phosphorus in the Digestive Tract of Poultry

^{Springer Science+Business Media, LLC, part of Springer Nature 2018}

Abstract
Probiotics are beneficial microorganisms and have long been used in food production as well as health promotion products. Bioengineered probiotics are used to express and transfer native or recombinant molecules to the mucosal surface of the digestive tract to improve feed efficiency and promote health. Lactococcus lactis is a potential probiotic candidate to produce useful biological proteins. The aimof this investigation was to develop a recombinant Lactococcus lactiswith the potential of producing phytase. To enhance the efficiency of expression and secretion of recombinant phytase, usp45 signal peptide was added to the expression vector containing phytase gene (appA2) derived from Escherichia coli. Sequencing of recombinant plasmid containing appA2 showed the correct construction of plasmid. Total length of the phytase insert was 1.25 kbp. A Blast search of the cloned fragment showed 99% similarity to the reported E. coli phytase sequence in the GenBank (accession number: AM946981.2). A plasmid containing usp45 and appA2 electrotransferred into Lactococcus lactis. Zymogram with polyacrylamide
gel revealed that the protein extract from the supernatant and the cell pellet of recombinant bacteria had phytase activity. Enzyme activity of 4 U/mlwas obtained in cell extracts, and supernatantmaximal phytase activity was 19 U/ml. The recombinant L. lactis was supplemented in broiler chicken feed and showed the increase of apparent digestibility on phytate phosphorus in the digestive tract and it was same as .performance of E. coli commercial phytas