Novel biobutanol fermentation at a large extractant volume ratio using immobilized Clostridium saccharoperbutylacetonicum N1-4

• Published in: Journal of bioscience and bioengineering Vol. 126; no. 6; pp. 750 - 757
• Main Authors: Darmayanti, Rizki Fitria, Tashiro, Yukihiro, Noguchi, Takuya, Gao, Ming, Sakai, Kenji, Sonomoto, Kenji
• Format: Journal Article
• Language: English
• Published: Japan Elsevier B.V 01.12.2018
• Subjects: 1-Butanol - isolation & purification; 1-Butanol - metabolism; Acetone - isolation & purification; Acetone - metabolism; Batch Cell Culture Techniques - methods; Butanol production; Butanols - isolation & purification; Butanols - metabolism; Cells, Immobilized - metabolism; Chemical Fractionation - methods; Clostridium - metabolism; Clostridium saccharoperbutylacetonicum; Ethanol - isolation & purification; Ethanol - metabolism; Extractive fermentation; Fermentation; Immobilization; Large extractant volume ratio; Oleyl alcohol-tributyrin mixture; Clostridium saccharoperbutylacetonicum; Immobilization; Butanol production; Large extractant volume ratio; Extractive fermentation; Oleyl alcohol-tributyrin mixture
• ISSN: 1389-1723; 1347-4421
• DOI: 10.1016/j.jbiosc.2018.06.006

Product inhibition by butanol and acetone is a known drawback in acetone-butanol-ethanol (ABE) fermentation. Extractive fermentation improves butanol production by several ABE-producing Clostridium spp., but only low volume ratios (<4) of extractant to broth (Ve/Vb) have been studied. Here, a novel extractive fermentation process was developed using Clostridium saccharoperbutylacetonicum N1-4 and a large Ve/Vb ratio. A mixture of oleyl alcohol-tributyrin (1:1 (v/v)) yielded high distribution coefficients for both butanol (3.14) and acetone (0.660). Although a fed-batch culture using free cells and the oleyl alcohol-tributyrin mixture at a Ve/Vb ratio of 5 had a lag phase of >24 h, it produced a higher concentration of total butanol (i.e., butanol produced in all the phases per broth volume used) of 24.2 g/L-broth after 96 h compared with 14.4 g/L-broth at a Ve/Vb ratio of 1, resulting in a low butanol concentration in the aqueous phase. The use of cells immobilized with calcium alginate beads shortened the lag phase to <12 h. Butanol production was achieved not only in a 3-phase mode (extractant, beads, and tryptone-yeast extract-acetate (TYA) medium) but also in a 2-phase mode (extractant and beads containing TYA medium, without an aqueous phase) at a Ve/Vb ratio of 5, resulting butanol concentrations of 30.9 g/L-broth and 27.7 g/L-broth, respectively. The 3-phases fed-batch extractive fermentation at a Ve/Vb ratio of 10 showed a better performance compared with published reports: a total butanol concentration of 64.6 g/L-broth and a butanol yield to consumed sugar of 0.378 C-mol/C-mol. [Display omitted] •New extractant mixture led to simultaneous extraction of butanol and acetone.•Large extractant volume maintained lower butanol concentration in media.•Extractive fermentation with immobilization succeeded using the minimized volume of media solution.•Large volume ratio of extractant to broth resulted in high total butanol concentration.