Impact of pH and butyric acid on butanol production during batch fermentation using a new local isolate of Clostridium acetobutylicum YM1

Abstract

The effect of pH and butyric acid supplementation on the production of butanol by a new local isolate of YM1 during batch culture fermentation was investigated. The results showed that pH had a significant effect on bacterial growth and butanol yield and productivity. The optimal initial pH that maximized butanol production was pH 6.0 ± 0.2. Controlled pH was found to be unsuitable for butanol production in strain YM1, while the uncontrolled pH condition with an initial pH of 6.0 ± 0.2 was suitable for bacterial growth, butanol yield and productivity. The maximum butanol concentration of 13.5 ± 1.42 g/L was obtained from cultures grown under the uncontrolled pH condition, resulting in a butanol yield ( ) and productivity of 0.27 g/g and 0.188 g/L h, respectively. Supplementation of the pH-controlled cultures with 4.0 g/L butyric acid did not improve butanol production; however, supplementation of the uncontrolled pH cultures resulted in high butanol concentrations, yield and productivity (16.50 ± 0.8 g/L, 0.345 g/g and 0.163 g/L h, respectively). pH influenced the activity of NADH-dependent butanol dehydrogenase, with the highest activity obtained under the uncontrolled pH condition. This study revealed that pH is a very important factor in butanol fermentation by YM1.

Simultaneous saccharification and fermentation of sago hampas into biobutanol by Clostridium acetobutylicum ATCC 824

“…Although the biobutanol yield in SSF is slightly lower than SHF, SSF could still provide a better productivity than SHF besides its advantages in reducing the number of steps, time, and apparatus . The initial pH was set at pH 5.5 based on previous studies . The pH was dropped to 4.9 after 24 hour of fermentation due to the formation of acids indicating the acidogenic phase of the ABE fermentation and slightly increased during the solventogenic phase.…”

“…11 The initial pH was set at pH 5.5 based on previous studies. 11,53,54 The pH was dropped to 4.9 after 24 hour of fermentation due to the formation of acids indicating the acidogenic phase of the ABE fermentation and slightly increased during the solventogenic phase.…”

Isolation of nativeClostridiafor utilization of agroindustrial cherry waste into butanol

“…27 A critical point is the pH because it has been seen that it is related to the production and yield in the solventogenic phase of the ABE fermentation. Therefore, according to Al-Shorgani et al, 28 the pH should range between 5.0 and 6.5, and at pH 6.0 it has shown that the concentration of H+ ion remains within the physiological range, which prevents sporulation and allows the generation of butanol. 17 Of the five native isolates of Clostridium, strains C9FD1, C3FD11, and C14FY8 produced butanol, (data shown in Table 5).…”

Optimization of Batch Dark Fermentation of Chlorella sp. Using Mixed-Cultures for Simultaneous Hydrogen and Butyric Acid Production

“…The reduction of pH demonstrates that hydrogen production occurred in the fermentation process. However, the decrease in low pH would greatly inhibit the metabolism of bacterial growth and cause a decrease in hydrogen production [52].…”

“…On the other hand, fermentation at initial pH 7 and any concentration or temperature can produce VFAs with higher yield. However, the decrease in low pH would greatly inhibit the metabolism of bacterial growth and cause a decrease in hydrogen production [52].…”