Efficient Phytase Secretion and Phytate Degradation by Recombinant Bifidobacterium longum JCM 1217

Abstract

Genetic engineering of probiotics, like bifidobacteria, may improve their microbial cell factory economy. This work designed a novel shuttle plasmid pBPES, which bears exogenous <i>appA</i> and is stable within <i>Bifidobacterium longum</i> JCM 1217. Cloning of three predicted promoters into pBPES proved that all of them drive appA expression in <i>B. longum</i> JCM 1217. Transformation of plasmids pBPES-tu and pBPES-groEL into <i>B. longum</i> JCM1217 resulted in much more phytase secretion suggests P <i>_tu</i> and P <i>_groEL</i> are strong promoters. Further <i>in vitro</i> and <i>in vivo</i> experiments suggested <i>B. longum</i> JCM 1217/pBPES-tu degrades phytate efficiently. In conclusion, the study screened two stronger promoters and constructed a recombinant live probiotic strain for effectively phytase secretion and phytate degradation in gut. The strategy used in the study provided a novel technique for improving the bioaccessibility of phytate and decreasing phosphorus excretion.