Continuous production of ethanol by use of respiration deficient mutant yeast

Abstract From the Canadian patent

This invention provides a process for producing ethanol from a D-sugar in a continuous aerobic environment using a flocculant respiration-deficient mutant of Saccharomyces uvarum in a single stage fermentor with a cell settling tank and cell recycle, at a productivity of more than 50 grams ethanol per liter fermentor volume per hour. The process comprises (a) inoculating a fermentation zone with a respiration-deficient mutant of Saccharomyces uvarum; (b) feeding a mixture of a D-sugar a, nitrogen source, a vitamin source and a mineral source into the fermentation zone in the presence of oxygen and (c) fermenting, the D-sugar mixture for a sufficiently long period of time to yield an ethanol …