Effects of acetic and butyric acids on solvents production by Clostridium acetobutylicum

Butyrate production in continuous culture of Clostridium tyrobutyricum: effect of end-product inhibition

“…With C. butyricum Heyndrickx et al (1986) observed no effect of added acetate or butyrate on the spectrum of products formed, but the utilization and conversion into solvents of acid either added or produced during fermentation is well known for C. acetobutylicum (Peterson and Fred 1932;Martin et al 1983;Marchal et al 1985). …”

Biobutanol from Renewable Agricultural and Lignocellulose Resources and Its Perspectives as Alternative of Liquid Fuels

“…A 32 % conversion rate of the glucose into solvents took place when the same fermentation was carried out on a synthetic medium (BuOH:acetone:EtOH was 0.6:1.9:6). This was changed to 34 and 35 % (BuOH:acetone:EtOH was 5:3:6 or 0.8:2.4:6) by adding HOAc or butyric acid, respectively [66].…”

Production of Butyric Acid and Butanol from Biomass

“…As the external pH varied between 5.9 and 4.3, the cells kept a constant ∆pH of 0.9 to 1.3 (Gottwald and Gottschalk, 1985). Certain levels of butyric and acetic acid concentration are essential for the induction of butanol formation (Bahl, et al, 1982;Fond, et al, 1985;Gottschalk and Morris, 1981;Holt, et al, 1984;Martin, et al, 1983;Monot, et al, 1984;Terracciano and Kashket, 1986). But due to the complicated metabolic mechanisms involved during the induction of solvent formation, the exact concentration levels required still remains controversial.…”

“…With an elevated concentration of acids initially added to the medium, the induction of solvent production was initiated at an earlier stage, but it does not necessarily improve the final production of butanol (Gottschalk and Morris, 1981). It has been reported that at different initial acetic and butyric concentrations, the total solvent and the ratio of solvents (acetone/butanol/ethanol) to be produced was changed (Martin, et al, 1983). Several other parameters were also found to affect the butanol production, including temperature, vitamin concentrations and other medium compositions.…”