Directed evolution of an acid Yersinia mollaretii phytase for broadened activity at neutral pH


Congratulations to Catalina Novoa on her recent publication!

Phytases are phosphohydrolases that initiate the hydrolysis of phosphate from phytate, which is the main storage form of phosphorous in numerous plant seeds, especially in cereals and grains. Phytate is indigestible for most monogastric animals, such as poultry, swine, fish, and humans. Within the growing environmental awareness, the reduction of undigested phytate is of high interest.

  Scheme of Directed Evolution of Y.mollaretti phytase Copyright: Bio VI Scheme of Directed Evolution of Y.mollaretti phytase for broadened activity at neutral pH as described by Catalina Novoa


Phytases are routinely used as animal feed additive, with a market estimated to be worth $350 million per year. Since the gastrointestinal pH of animals varies from 1.5 to 8.0, phytases with a broader pH profile are industrially attractive for the improvement of phytate digestion in the gastrointestinal tract. In this work, a direct evolution campaign yielded improved variants with up to 7-fold increased specific activity at pH 6.6 under screening conditions. These results show a proof of concept that the acidic pH profile of bacterial phytases can be broadened to neutral pH values that occur in the small intestine.

This study was financed by the German Federal Ministry of Education and Research (BMBF) under the program Basistechnologien für die nächste Generation biotechnologischer Verfahren (FKZ 031A165).

Körfer, G. §, Novoa, C. §, Kern, J., Balla, E., Grütering, C., Davari, M.D., Martinez, R., Vojcic, and L., Schwaneberg, U. Appl Microbiol Biotechnol, 2018, DOI: 0.1007/s00253-018-9308-7

§ shared first authorship