The relationship between hydrogen gas and butanol production by Clostridium saccharoperbutylacetonicum

Abstract

Two simultaneous fermentations were performed at 26 degrees C with simultaneous inocula using Clostridium saccharoperbutylacetonicum. Fermentation 1 prevented the gas formed by the biomass from escaping the fermentor while 2 allowed the gas formed to escape. Fermentor 1 provided for the production of butanol, acetone, and ethanol, while when the H(2) formed was allowed to escape with fermentor 2, neither butanol nor acetone were produced. Ethanol was also formed in both fermentors and began along with the initial growth of biomass and continued until the fermentations were complete. Butanol and acetone production began after biomass growth had reached a maximum and began to subside. The butanol-acetone-ethanol millimolar yields and ratios were 38:1:14 respectively. The fermentor 2 results show that a yield of 2.1 L H(2), 93 or 370 mmol H(2)/mol glucose, was formed only during the growing stage of growth; neither butanol nor acetone were produced; ethanol was formed throughout the fermentation, reaching a yield of 15.2 mmolar. It appears that hydrogen gas is required for butanol production during the resting stage of growth.

Modeling and optimization of anaerobic digested sludge converting starch to hydrogen

“…Such a phenomenon is similar to that of Jones and co-workers (1982), who reported that VFAs (i.e., acetate and butyrate), but not solvents (i.e., butanol and acetone), are produced by Clostridium acetobutylicum during exponential growth. Obviously, the growth response of hydrogen-producing microorganisms obtained from the chemostat reactor was in general good agreement with that of Clostridium sp.-consuming carbohydrates in normal-batch culture (Afschar et al, 1986;Brosseau et al, 1986;Jones et al, 1982;). As a result, it must be concluded that both influences of pH and HRT in starchhydrogen fermentation corresponded closely to its metabolic control.…”

“…3A, C, D) show that the production trends of hydrogen/VFA were clearly opposite to that of alcohols. This mechanism is remarkably similar to that of Clostridium sp.-consuming carbohydrates, such as glucose and sucrose (Afschar et al, 1986;Brosseau et al, 1986;Jones et al, 1982;). Previous studies (Lay et al, 1999a(Lay et al, , 1999b(Lay et al, , 1999c have demonstrated that the boiling of sludge can readily deactivate hydrogentrophic bacteria and has a great potential to enhance the sludge's clostridial characteristics.…”

“…form VFAs during the exponential-growth phase. Only during the late-growth phase does the metabolism shift to rapid alcohol production in normal-batch culture (Afschar et al, 1986;Brosseau et al, 1986;Jones et al, 1982).…”

“…Interest in the industrial application of anaerobic bacteria to generate chemically useful substances emerged in the early 1970s because of the oil shortage (Brosseau et al, 1986;Jones et al, 1986). Of these chemicals, hydrogen would provide clean power generation and would promote design of high-efficiency automobiles.…”

Biohydrogen generation by mesophilic anaerobic fermentation of microcrystalline cellulose

“…For example, when Clostridium pasteurianum are grown in high glucose concentrations significant quantities of alcohols are produced (Harris et al, 1986). Brosseau et al (1986) also reported that the hydrogen was produced in the cell growth phase, whereas the cells produced butanol at equilibrium. The efficiency of a hydrogen-producing bioprocess depends highly upon optimal control of factors such as the ratio of substrate concentration to biomass concentration.…”