Cellulose Fermentation by an Asporogenous Mutant and an Ethanol-Tolerant Mutant of Clostridium thermocellum.
Two mutants of Clostridium thermocellum were isolated after UV light mutagenesis. Mutant A1, selected as asporogenous, exhibited a fermentation pattern similar to that of the wild type. However, at pH 6.5, the mutant degraded 12% more cellulose than did the wild type, leading to enhanced ethanol production. Mutant 647, selected as ethanol tolerant, was able to grow in medium containing 4% ethanol. During the early stage of the exponential growth phase, ethanol was produced as the main product, up to a concentration of about 9 g/liter. After 3 days of culture, 48.3 g (89% of the initial amount) of degraded cellulose per liter was fermented into 12.7 g of ethanol per liter.
Tailliez
P
P
Unité de Physiologie Cellulaire et URA 209 CNRS, Département des Biotechnologies, Institut Pasteur, 28, rue du Dr Roux, 75724 Paris Cedex 15, France.
Girard
H
H
Longin
R
R
Beguin
P
P
Millet
J
J