Adsorption to soils and biochemical characterization of purified phytases

CAFFARO MM; BALESTRASSE K; RUBIO G

Soil

Copernicus

Año: 2020

2199-3971

Four purified phytases isolated from Aspergillus niger and Escherichia coli were characterized biochemically and in terms of their adsorption to soils belonging to the Mollisol order. Three different organic P substrates were used to measure enzyme activity in a wide range of pH (2.3 to 9) and temperatures (-10º to 70ºC): phytic acid, p-nitrophenyl-phosphate (pNP) and glyceraldehyde-3-phosphate (G3Phosphate).. Phytases had low affinity for the solid phase: 23-34% adsorbed after one hour of incubation. Phytases from A. niger showed a higher capacity to release P (13% on average), than phytases from E. coli. All phytases were active throughout the pH and temperature ranges for optimum crop production. At pH values commonly found in agricultural soils (5.5-7) A. niger phytases released P following the ranking of substrates : pNP > phytic acid > G3Phosphate, whereas E. coli phytases released P following the ranking: pNP / phytic acid > G3Phosphate. Obtained results are promising in terms of the use of phytases as a complement to P fertilization in agricultural settings and encourages further studies under field conditions.