Biochemical properties of phytase immobilized and its effect on growth parameters of tomato

Abstract

BackgroundPhosphorus (P) is one of the nonrenewable resources of critical importance in agricultural production. P is present in soil in organic and inorganic forms. Phytate constitutes the majority of organic P in soil. Phytate binds strongly to the solid phase of the soil and becomes unavailable for use by plants. Therefore, the soluble phytate‐P ratio in soil is mostly at very low levels. Plants and associated microorganisms secrete organic acids and hydrolyzing enzymes such as phytase to dissolve phytate in the soil. Both the solubility of phytate and phytase activity are limiting properties for the uptake of phytate‐P by plants.AimsOur aim was to evaluate the effects of phytase immobilized on zinc oxide nanoparticles (ZnO Np) on tomato plant (Solanum lycopersicum) growth parameters. In this study, seedling period was analyzed.MethodsIn the study, phytase activity of 13 different bacteria was investigated, and phytase was purified from Lactobacillus kefiri, showing the highest activity, and its biochemical properties were determined. Phytase was immobilized on zinc oxide (ZnO) nanoparticles and characterized by X‐ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopes analysis. The effects of ZnONps, immobilized phytase, and free phytase on the growth parameters of tomato plant were investigated. Tomato seeds were soaked with ZnONps, immobilized and free phytase for 30 min at room temperature and sown in pots containing suitable growing medium. Vegetative development of tomato plant, plant height, number of lateral branches, main stem diameter, distance between nodes, number of nodes, main root, and shoot length were determined.ResultsPhytase was partially purified with 7.60% recovery and specific activity of 1758.5 (EU mg−1 protein). Molecular mass of partially purified phytase was approx.72 kD, optimum pH and temperature values were determined as pH 5.0 and 70–80°C, respectively. Immobilized phytase caused a significant increase of 41.1% in plant height, 64.1% in main root, and 36.1% in shoot length in tomato plants compared to the control. In addition, a significant increase was observed in the number of side branches, main stem diameter, distance between nodes, number of nodes, and vegetative growth of the plant.ConclusionsThe results showed that the immobilized phytase enzyme has a positive effect on seedling growth in tomato and can be used in tomato cultivation in the future.