Purification and characterization of a novel cold-adapted phytase from Rhodotorula mucilaginosa strain JMUY14 isolated from Antarctic.

摘要: A yeast producing a cold-adapted phytase was isolated from Antarctic deep-sea sediment and identified as Rhodotorula mucilaginosa strain JMUY14 of basidiomycetous yeasts. It cultured in fermentation optimized by response surface methodology based on the Box-Behnken design. The maximum activity reached 205.447 U ml(-1), which close to predicted value 201.948 ml(-1) approximately 3.4 times higher than its initial activity. extracellular purified 15.2-fold homogeneity with specific 31,635 mg(-1) (NH4 )2 SO4 precipitation, combination DEAE Sepharose Fast Flow, SP Sephadex G-100. molecular weight enzyme estimated be 63 kDa pI 4.33. Its optimal temperature pH were 50 °C 5.0, respectively. 85% at 37 °C, showed good stability 3.0 ∼ 7.0. When compared mesophilic counterparts, not only exhibited during 20 30 but also had low Km (247 µM) high kcat (1394 s(-1)). slightly stimulated presence Mg(2+), Fe(2+), Fe(3+), K(+), Na(+), Ca(2+), EDTA, EGTA moderately inhibited Cu(2+), Zn(2+), Mn(2+), Ag(+), PMSF, SDS, phenylgloxal hydrate. resistant both pepsin trypsin. Since produced R. activity, stability, strong protease resistance, temperature, it has great potential for feed applications, especially aquaculture.