An aroma like bread dough permeates Raul Cano's lab. He has just removed the cover from a petri dish, and the odor wafts up from several gooey yellow clumps of microorganisms that have been feeding and reproducing in a dark cabinet for the past few days. Cano, a 63-year-old microbiologist at California Polytechnic State University, San Luis Obispo, inspects the smelly little mounds lovingly. "These are my babies," he says, beaming. "My yeasty beasties."
The dish contains a variant of Saccharomyces cerevisiae, known in culinary circles as baker's or brewer's yeast. But Cano didn't get this from Whole Foods. Back in 1995, he extracted it from a 45 million-year-old fossil. The microorganisms had lain dormant since the Eocene epoch, a time when Australia split off from Antarctica and modern mammals first appeared. Then Cano brought the yeast back to life.