[Expression of alpha-acetolactate decarboxylase gene from Bacillus subtilis in Brewer's yeast]

Yeast YIp-type expression recombinant plasmid(pCMA2-1) was constructed. The expression of alpha-acetolactate decarboxylase gene from Bacillus subtilis was controled by CUP1 promoter and its own terminator. The recombinant plasmid pCMA2-1 was introduced into the brewer's yeast PJ3-5. Transformants were selected using copper resistance as selected marker. The results of activity assay showed that PJ3-5 didn't produce alpha-acetolactate decarboxylase(ALDC), where as the activity of alpha-ALDC in transformants were induced by copper sulfate. The laboratory scale fermentation test confirmed that the total diacetyl concentration was reduced effectively by alpha-ALDC in transformant.