endonucleases EcoRI/ BamHI. The length of the insert fragments derived from restriction digestion was about 1.1 kb. The correction of the inserted gene was confirmed by sequencing. The pSFAU-XDH vector was transformed into S. cerevisiae TISTR 5339, by which the transformants were selected by their abilities to grow on media containing 5.5 mM formaldehyde.