Abstract

Some free living microorganisms in soil have the capability to produce extracellular enzymes such as phosphatase. This enzyme is able to mineralize organic phosphates into inorganic phosphates that provides high P for plant. Exploration and laboratory experiments were carried out to obtain the most excellent bacterial isolates for producing phosphatase and solubilizing phosphate and also to study the capabilities of pre-eminent isolates to hydrolyze synthetic and natural organic phosphate. Exploration and selection processes resulted in ten isolates which were then tested to examine their capabilities to hydrolyze synthetic organic phosphate (phytic acid) and natural organic phosphate (extract of cow dung manure). Three pre-eminent isolates [Bacillus mycoides (obtained from rhizosphere of Gleichenia linearis), Bacillus laterosporus(from rhizosphere of Lithocarpus sundaicus) and Flavobacterium balustinum (fromrhizosphere of Altingia excelsa)] were found to have excellent capabilities in mineralizing organic phosphate. Hydrolysis of organic phosphate was affected by the types of organic P substrates. Phytic acid as organic P substrate gave higher phosphatase activity and dissolvedP higher than the extract of cow dung manure.

Key words: Phosphatase, hydrolyze, organic phosphate P, Sanggabuana.