Yeast aren't wimps. Dry yeast spring back to life for making bread. Frozen yeast thaw and rise to the occasion. Wine-making yeast keep working until the alcohol content in their brew hits 12 percent. Still, yeast have their limits. Now, UC Davis microbiologists have found a new way to push these limits. They've made a kind of "superyeast" that grows twice as well as normal yeast after being frozen, dehydrated or during brewing. Ordinary yeast can survive harsher conditions than most organisms, apparently because of a special sugar within yeast cells called "trehalose." Yet, yeast cells also produce an enzyme that breaks it down, limiting the sugar's powers. UC Davis researchers have discovered how to eliminate the gene required for that sugar-eating enzyme activity, giving superpowers to yeast. Commercially, this new strain may be able to make bread rise in half the time. It may survive longer in frozen dough and may be required in less quantities to produce the same amount of dough, says Daniel Klionsky, an associate professor of microbiology. Graduate student John Kim, Klionsky and other co-authors report their findings in this month's issue of Applied and Environmental Microbiology. A patent is pending.