The influence of support structures on cell immobilization and acetone-butanol-ethanol (ABE) fermentation performance

Cell immobilization is an efficient technique for achieving high-cell density; it has been shown to benefit acetone-butanol-ethanol (ABE) fermentation. In this study, the biodegradable material, poly(3-hydroxybutyrate) (PHB), was fabricated into plate-like structures by solvent casting (SC) and into fibrous structures by wet jet (WJ) and electrospinning (ES). The BET data showed that the specific surface areas of PHBsc, PHBwj, and PHBEs were 0.17, 18.30, and 22.45 m(2)/g, respectively. Butanol yields of 0.25 +/- 0.04, 0.28 +/- 0.01, and 0.20 +/- 0.01 g-butanol/g-glucose were obtained for PHBsc, PHBwj, and PHBEs during batch ABE fermentation. OD600 of fermentation broths that contain PHBsc, PHBwj, and PHBEs can be used to evaluate the immobilization ability. It was found that while OD600 of fermentation broths without an immobilization material was 12.0 +/- 1.6, OD600 of fermentation broths containing PHBwj was 4.3 +/- 0.3, which was the best for the three PHB materials tested. In summary, a high specific surface area with a pore size up to several hundred microns is recommended. The robustness and stability of PHB as an immobilization material for ABE fermentation was clearly confirmed. (C) 2017 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.