Investigating the Bioconversion of Tyrosol to Hydroxyltyrosol by Recombinant Bacillus Subtilis Spores and the Anticancer Effects of Hydroxytyrosol on MCF-7

Tyrosol (2-(4-Hydroxyphenyl) ethanol) is one of the natural phenolic compounds in olive which has antioxidant and anticancer effects. During the olive oil mill process, a lot of the phenolic compounds are released into the water which can contaminate the environment.However, these can be converted into useful ingredients and valuable dietary supplements. In the present study, tyrosol was converted to hydroxytyrosol by spore displayed tyrosinase and the anticancer effect of hydroxyl tyrosol was studied on MCF-7 breast cancer cells.

Spore suspension of the recombinant Bacillus subtilis DB104 (pSDJH-cotE-tyr), constructed in our previous research by genetic engineering methods and surface display technique, was prepared in sporulation medium. The spores were used in the bioconversion of tyrosol to hydroxytyrosol and the reaction was assayed by high-performance liquid chromatography. The anticancer effect of hydroxytyrosol on the MCF-7 breast cancer cell line was studied by a flow-cytometer.

The results of the study revealed that 1mM of tyrosol was converted to 1mM of hydroxytyrosol after 60 min. The anticancer effect of hydroxytyrosol on MCF-7 was determined more than 80% after 48 h incubation.

According to the obtained results, spore displayed tyrosinase as an active enzyme is able to produce useful compounds with anti-cancer properties from olive oil derivatives. The anti-cancer effects of hydroxytyrosol produced by biotransformation of tyrosol on MCF-7 breast cancer cells are confirmed by previous studies.