Question

Josephine works in a biology lab at UCLA and they have recently come up with a magic strain of bacteria that converts cellulose (the dominant organic component of grass clippings) into glucose. To create ethanol fuel, Joe and Josephine put the wet grass clippings into barrels, and then add an equal mass of water, plus a cup of the magic bacteria and then they let it sit for two weeks while the cellulose is converted to glucose. Then, Joe takes the resulting glucose solution and adds yeast to ferment the solution to produce a 15% ethanol solution, which takes an additional week. Then, every week, he burns additional grass clippings in a large still to distill the 15% ethanol solution to create a 95% ethanol solution.
The resulting distillate is clean-burning fuel, which Joe uses to power his riding mower, which he has, of course, modified to run on ethanol. Ignoring the fact that the magic strain of bacteria doesn’t really exist, will this scheme work?

Answer 1

Answer:

Yes, I think this scheme can work. The chippings will provide enough ethanol to power the mower. The mover requires up to 15% ethanol. As he is distilling it to 95% ethanol, it would be more than enough for the mower to work. And also he can use the remaining ethanol for other purposes like powering Joe’s car or to create alcoholic beverages to drink when Joe’s friends come over to watch UCLA football games on Saturday afternoons.