[Cloning of neutral phytase gene nphy from Bacillus subtilis and its expression in Escherichia coli]

The gene encoding the neutral phytase nphy was cloned from Bacillus subtilis by polymerase chain reaction (PCR). Nucleotide sequence analysis of nphy revealed the presence of an open reading frame of 1152 bp coding for 383 aa. The start codon was followed by a sequence coding for a putative signal peptide of 26 aa in length. The nphy without original signal peptide encoding sequence was cloned into E. coli expression plasmid pTYB40. The result of SDS-PAGE of the phytase expressed in E. coli showed that the nphy had been overexpressed. The expressed phytase was over 40% of the total soluble protein of E. coli, and has normal bioactivity.