Models construction for acetone–butanol–ethanol fermentations with acetate/butyrate consecutively feeding by graph theory

• Published in: Bioresource technology Vol. 159; pp. 320 - 326
• Main Authors: Li, Zhigang, Shi, Zhongping, Li, Xin
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.05.2014; Elsevier
• Subjects: Acetates; Acetates - metabolism; Acetone; Acetone - metabolism; Acids feeding; Biological and medical sciences; Bioreactors - microbiology; Biotechnology; Butanols - metabolism; Butyrate/acetate ratio; Butyrates - metabolism; Clostridium acetobutylicum - metabolism; Construction; Ethanol - metabolism; Feeding; Fermentation; Fundamental and applied biological sciences. Psychology; Glucose - metabolism; Graph theory; Hydrogen-Ion Concentration; Mathematical models; Metabolic Networks and Pathways; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Model construction; Models, Theoretical; Solvents; Solvents productivities; Time Factors; Solvents productivities; Acids feeding; Graph theory; Model construction; Butyrate/acetate ratio; Productivity; Ethanol; Acetate; Modeling; Feeding; Butyrate; Acids; Alcoholic fermentation; Butanol; Solvent; Acetone
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2014.02.095

•Consecutively feeding acetate/butyrate enhanced fermentation performance.•A nonlinear constraint used for acids metabolic rates calculation.•Incomplete acid loop appeared when acetate/butyrate was fed.•Graph theory models for acid feeding fermentations were constructed.•The models predicted solvents production and butanol/acetone ratios accurately. Several fermentations with consecutively feeding of acetate/butyrate were conducted in a 7L fermentor and the results indicated that exogenous acetate/butyrate enhanced solvents productivities by 47.1% and 39.2% respectively, and changed butyrate/acetate ratios greatly. Then extracellular butyrate/acetate ratios were utilized for calculation of acids rates and the results revealed that acetate and butyrate formation pathways were almost blocked by corresponding acids feeding. In addition, models for acetate/butyrate feeding fermentations were constructed by graph theory based on calculation results and relevant reports. Solvents concentrations and butanol/acetone ratios of these fermentations were also calculated and the results of models calculation matched fermentation data accurately which demonstrated that models were constructed in a reasonable way.