Thermophilic Microbes in Ethanol Production

This document considers the use of thermophilic bacteria and thermotolerant yeasts for ethanol production. It reviews general and specific properties of thermophilic ethanol-producing bacteria and assesses their relative merits in ethanol production. The main focus concerns employment of these bacteria in mono- and co-culture fermentations for ethanol production from cellulosics; in particular, the cellulase system of Clostridium thermocellum and ways of improving it are examined. This review discusses thermotolerant yeasts and physiological factors influencing their growth and fermentation at high temperatures. Special emphasis is on the multidisciplinary approaches required to develop economical processes for fermentation ethanol production at high temperatures. Relevant topics in this section include: adaptation, nutrition, heat shock, ethanol tolerance, metabolic control, genetic improvement, and fermentation/process design. General aspects of thermophily for both bacteria and yeasts (definitions, ecological aspects, merits and limitations, other industrial uses, thermostability of cellular components, and consequences of thermophilic fermentation) are also discussed.