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Importance of agitation in acetone‐butanol fermentation
Author(s) -
Yerushalmi Laleh,
Volesky Bohumil
Publication year - 1985
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.260270905
Subject(s) - clostridium acetobutylicum , acetone , butanol , fermentation , chemistry , solvent , yield (engineering) , butyric acid , ethanol , n butanol , chromatography , biochemistry , materials science , metallurgy
The specific rates of anaerobic solvent production by Clostridium acetobutylicum increased with increasing fermentor impeller speed from 190 to 340 rpm ( N Re = 3.93 × 10 4 ). The maximum values were 5.54, 3.85, and 0.8 mmol/h · g cell for butanol, acetone, and ethanol, respectively. Corresponding rates for respective gases produced were 11.60 and 15.88 mmol/h · g cell for H 2 and CO 2 . Further increases in agitation speed resulted in generally decreasing specific production rates to the point of inactive fermentation at 560 rpm. A competition observed between the cellular subsystems for butanol + butyric acid and biomass biosynthesis was evaluated through expressing the energetic yield coefficients. An imbalance between the production and outflux of the former metabolites is apparently further enhanced by a mechanical damage of the cells at high shear rates. A correlation was developed between the production of gases and solvents pointing at both H 2 ‐to‐solvent as well as CO 2 ‐to‐solvent ratios following the same pattern, peaking at 410 rpm.