PHOSPHATASES AND THE UTILIZATION OF ORGANIC PHOSPHORUS BY RHIZOBIUM-LEGUMINOSARUM BIOVAR VICEAE

Rhizobium leguminosarum biovar viceae strain TAL 1236 growing on diffe rent organic phosphorus compounds as sources of phosphate exhibited ph osphatase activities. The strain was able to produce both acid and alk aline phosphatases. However, its ability to produce alkaline phosphata se was much higher. When cellular phosphate fell to 0.115% of cell pro tein, cellular and extracellular phosphatase activities were promoted. Mg2+, Co2+ and Ca2+ enhanced slightly the activity of alkaline phosph atase more than acid phosphatase. However, Mn2+ and Fe2+ activated aci d phosphatase rather than alkaline phosphatase. It may be concluded th at Rh. leguminosarum plays an important role in the release of phospho rus from its organic compounds through the action of phosphatases whic h can be slightly activated by a range of cations.