HYDROLYSIS OF PHYTATE PHOSPHORUS IN SOILS

Abstract

The hydrolysis of native soil organic P by added phytase and the hydrolysis of added phytate P by soil phytase were detd. on 6 samples of soils brought from the field and tested without previous drying. There was substantial hydrolysis of added phytate P by soil phytase, but there was no detectable hydrolysis of soil organic P by added phytase. The limited amount of phytate P in soln. in the soils was thus a deterrent to rapid hydrolysis of soil phytate P. Either the amt. of phytase present was adequate to produce the max. hydrolysis rate of soil phytate P or the increase in hydrolysis rate produced by the added phytase was within the exptl. error of measurement. Appln. of the Michaelis and Menten theory of enzyme action to the data made possible the estimate that the amount of soil phytate P in soln. was at least 71 times as important as the phytase activity in limiting the hydrolysis rate of soil phytate P.