[Alpha-acetolactate decarboxylase from B. licheniformis AS10106: cloning and expression gene in E. coli and S....

A genomic library of B. licheniformis AS10106 that contained the alpha-acetolactate decarboxylase gene(alpha-ALDC) was constructed with vector pUC19 and host E. coli JM109 strain. The inserted fragments of foreign DNA ranged from 4 to 10 kb in the 4800 clones thus obtained. Six positive clones were detected after screening the plated library by the method of clony coloration. Subcloning of the DNA fragment containing the alpha-acetolactate decarboxylase gene showed that the alpha-acetolactate decarboxylase gene was on an 1.6 kb BamH I-EcoR I fragment. Preliminary analysis of the enzyme expressed from one recombinant plasmid pGEA showed that the properties of the recombinant enzyme, such as the optimal temperature and pH of reaction, were identical to those of the native enzyme. Using yeast-E. coli shuttle vector pYES2, an expression recombinant plasmid pYEA containing B. licheniformis AS10106 alpha-acetolactate decarboxylase gene was constructed. S. cerevisiae H158 transformed with pYEA had expressed alpha-acetolactate decarboxylase activity and shown the ability to reduce the formation of diacetyl during beer fermentation.