A biologically pure mutant of C. thermoaceticum (ATCC No. 39,289) useful for the production of acetic acid by a fermentation reaction. This mutant is capable of growing at a pH below 5.0 and shows a specific growth rate of at least 0.30 hr.sup.-1 when continuously cultured under optimum conditions.
An improved process for obtaining fructosyl transferase enzyme from the yeast Aureobasidium pullulans. Prior purification process steps are eliminated by use of conditions which do not produce black pigments and viscous polysaccharides.