Engineered Yeast Turns Old Plastic Bottles Into Vanilla Cookies

Southern Illinois University researchers engineered yeast to break down PET plastic and crop waste, then rebuild the carbon into protein-rich, vanilla-flavored 'microbites' - 3D-printed cookies aimed at disaster zones, submarines and deep space.

Your next snack could start out as a discarded soda bottle. A team at Southern Illinois University Carbondale has engineered yeast to break down PET plastic and agricultural waste, then rebuild the carbon into protein-rich, vanilla-flavored cookies they call µBites - pronounced "microbites."

The recipe begins with a process called oxidative hydrothermal dissolution, which uses water and oxygen under intense heat and pressure to shred plastic bottles and leftover corn stalks into their carbon building blocks. Those fragments are fed to engineered strains of yeast - including baker's yeast - which convert them into proteins, lipids and vitamins. One strain is programmed to produce vanillin for a vanilla aroma, another to make beta-carotene, the compound that colors carrots and becomes vitamin A in the body.

Fiber, starch and sweetener are mixed in, then the dough is piped through a 3D food printer and microwaved into a firm cookie. No one has eaten one yet: the team, led by microbiologist Lahiru Jayakody, is awaiting approval for human taste tests. Accredited third-party labs have found the cookies free of toxic chemicals, heavy metals, allergens and pathogens, and simulated digestion studies are underway ahead of human trials.

The work grew out of NASA's Deep Space Food Challenge and was presented at the fall meeting of the American Chemical Society in Chicago. The system currently converts more than half of the carbon in its waste feedstock into food, and the portable, self-contained unit could one day feed crews in submarines, disaster-relief operations, the desert, the Arctic - or Mars.

Sources: ScienceAlert, The Brighter Side of News