Bioconversion of Daidzein to 3ʹ-ODI by Bacillus Subtilis Spore Displayed Tyrosinase

Bacillus subtilis spore surface display technique has long been used to display antigens and enzymes for medical and industrial proposes. In this technique, the enzyme is genetically immobilized on the spore surface and one of the capabilities of spore displayed enzyme is the reusability. In this study, spore displayed tyrosinase was used for the bioconversion of soybean extracted daidzein to more hydroxylated, anticancer compound, 3ʹ-ODI.

Bacillus subtilis DB104 (pSDJH-cotE-tyr) which was constructed in our previous study was used as an enzyme source. The reaction was done in 37˚C for 1 hour. To detect the product of the reaction, high-performance liquid chromatography was used.

The results revealed that 1mM of daidzein was converted to about 1mM 3ʹ-ODI during 60 min by 4*108 spores. The retained activity of the spore displayed tyrosinase was also detected about 58% after three times usage. Discussion and

Spore surface displayed enzymes have created a new way to improve enzyme stability and reusability. Our results showed that active tyrosinase on the surface of the spores has the potential to be used in industrial conditions to produce more hydroxylated isoflavones.