Abstract

Phytases (myo-inositol hexakisphosphate phosphohydrolase, EC 3.1.3.8) catalyze the release of phosphate from phytates. Many of the cereal grains, legumes and oilseeds store phosphorus in phytate form. Phytases can be produced by plants, animals and microorganisms. However, the ones with microbial origin are the most promising for commercial uses and biotechnological applications. In this study, phytase enzyme isolation from Lactobacillus spp. ATCC strain and its characterization was carried out. Phytase production from bacterial strains was determined by zone production formed around colonies after 48 h of incubation at 30°C in MRS medium. Optimum pH and optimum temperature values of the phytase enzyme that was partially purified by precipitation of ammonium sulphate from Lactobacillus plantarum, extracellularly from bacteria put into liquid culture medium, were measured. Optimum activity of the enzyme derived from L. plantarum bacterium was at 30°C and pH 6.0. It was observed that L. plantarum's extracellular enzyme maintains its 90% of activity at 10-100°C for 120 min. Effects of certain metal ions on activity of phytase enzyme derived from L. plantarum were also investigated. Of these, CuCl₂, MnCl₂, CoCl₂, CaCl₂ and ZnCl₂ decreased enzyme activity significantly. FeCl₂ increased enzyme activity by 121%. Based on these results, the phytase enzyme of L. plantarum is considered suitable for use in many industrial areas, in feed and food industries in particular, due to its thermal stability and resistance to metal ions.

Key words: Purification, characterization, phytase, Lactobacillus plantarum.