Alkaline Phosphatase−Polyresorcinol Complex: Characterization and Application to Seed Coating

Abstract

An alkaline phosphatase (EC 3.1.3.1) from Escherichia coli ATCC27257 was immobilized by copolymerization with resorcinol. The phosphatase−polyresorcinol complex synthesized retained about 74% of the original enzymatic activity. The pH and temperature profile of the immobilized and free enzyme revealed a similar behavior. Kinetic parameters were determined: Km and Ki values were 2.44 and 0.423 mM, respectively, for the phosphatase−polyresorcinol complex and 1.07 and 0.069 mM, respectively, for free phosphatase. The thermal and storage stabilities of the immobilized phosphatase were higher than those of the native one. On addition to soil, free enzyme was completely inactivated in 4 days, whereas the phosphatase−polyresorcinol complex was comparatively stable. Barley seed coated with the immobilized enzyme exhibited higher rhizosphere phosphatase activity. Under pot culture conditions, an increase in the soil inorganic phosphorus was detected when the seed was encapsulated with the phosphatase−polyresorcinol complex, and a positive influence on biomass and inorganic phosphorus concentration of shoot was observed.