Sulforaphene prepared from glucoraphenin by myrosinase is one of the main active ingredients of radish, which has various biological activities and brilliant potential for food and pharmaceutical applications. In this paper, a recombinant food-grade yeast transformant 20-8 with high-level myrosinase activity was constructed by over-expressing a myrosinase gene from Arabidopsis thaliana in Yarrowia lipolytica. The highest myrosinase activity produced by the transformant 20-8 reached 44.84 U/g dry cell weight when it was cultivated in a 10 L fermentor within 108 h. Under the optimal reaction conditions, 6.1 mg of sulforaphene was yielded from 1 g of radish seeds under the catalysis of the crude myrosinase preparation (4.95 U) at room temperature within 1.5 h. What is more is that when the whole yeast cells harboring myrosinase activity were reused 10 times, the sulforaphene yield still reached 92.53% of the initial level. Therefore, this efficient approach has broad application prospects in recyclable and large-scale preparation of sulforaphene.
Keywords: Yarrowia lipolytica; food-grade yeast; myrosinase expression; sulforaphene preparation; whole-cell catalysis.