Direct screening of libraries of yeast clones for alpha-amylase activity on raw starch hydrolysis.

High-throughput screening for high-activity barley alpha-amylase mutants expressed in Saccharomyces cerevisiae is hampered by the interference of reducing agents, particularly the glucose used in yeast growth media. The present investigation employed colorimetric and chemiluminescent detection systems that enable direct and rapid screening of activities on raw starch substrate. Active clones could be separated into two groups, based on high total activity or high specific activity.