Isolation of a Recombinant Bacillus sp. TS‐23 α‐Amylase by Adsorption‐Elution on Raw Starch

A Bacillus sp. TS‐23 α‐amylase produced by recombinant Escherichia coli was adsorbed onto raw starch and the adsorbed enzyme was eluted with maltose or maltodextrin in 50 mM Tris/HCl buffer (pH 8.5). The adsorption‐elution procedure resulted in a yield of 53% α‐amylase activity and sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS/PAGE) analysis showed that the eluted α‐amylase had a molecular mass of approximately 64 kDa. Raw starch could be used repeatedly in the adsorption‐ elution cycle with good reproducibility. Scanning electron microscopy of the isolated corn starch exhibited a smooth appearance of the granules before adsorption and only a small change in appearance after three adsorption‐elution cycles. These results suggest that the raw starch adsorption‐elution technique has a great potential in the isolation of Bacillus sp. TS‐23 α‐amylase from the culture broth of recombinant E. coli.