Purification and characterization of a novel phytase from Nocardia sp MB 36

Phytase from Nocardia sp. MB 36 was purified (9.65-fold) to homogeneity by acetone precipitation, ion exchange, and molecular sieve chromatography. Native polyacrylamide gel electrophoresis (PAGE) and zymogram analysis showed a single active protein in the purified enzyme preparation. Sodium dodecyl sulfate (SDS)-PAGE analysis showed that phytase was a monomeric protein with a molecular weight of approximately 43 kDa. Phytase exhibited activity and stability over a broad pH range (2-8) and elevated temperatures (50-80 degrees C), and utilized several phosphate compounds as substrates. Phytase was extremely resistant to pepsin and trypsin. Various metal ions viz. Fe2+, Co2+, and Mn2+, and NH4+, ethylenediaminetetraacetic acid or EDTA and phenylmethylsulfonyl fluoride or PMSF had no influence on activity, while Ca2+ and Zn2+ enhanced activity by 15 % and 3.58 %, respectively. SDS caused significant reduction in enzyme activity (41.8 %), while 2,3-butanedione did so moderately (15.9 %). Features of Nocardia sp. MB 36 phytase suggest a potential for animal feed applications.