Overexpression of ethionine resistance gene for maximized production of S-adenosylmethionine in Saccharomyces cerevisiae sake kyokai No. 6

In our previous work, we developed an auxotrophic mutant of Saccharomyces cerevisiae sake kyokai No. 6 strain for the selection of recombinant DNA. Sake yeast can accumulate high amount of S-adenosylmethionine (SAM) that is effective for treating depression, Alzheimer's disease and so on. In this work, we further introduced SAM2 gene and ERC1, a frame-shift mutant of YHR032w, to maximize the production of S-adenosylmethionine in S. cerevisiae sake K6. The recombinant strain accumulated SAM about half of its dry cell weight.