Continuous Ethanol Production with a Membrane Bioreactor at High Acetic Acid Concentrations

Membranes

Päivi Ylitervo²  Carl Johan Franzén¹ 

[1] Chemical and Biological Engineering—Industrial Biotechnology, Chalmers University of Technology, 412 96 Göteborg, Sweden; E-Mail:;Swedish Centre for Resource Recovery, University of Borås, 501 90 Borås, Sweden; E-Mail:

关键词: acetic acid;    membrane bioreactor;    bioethanol;    cell retention;    yeast;   

DOI  :  10.3390/membranes4030372

来源: mdpi

【 摘 要 】

The release of inhibitory concentrations of acetic acid from lignocellulosic raw materials during hydrolysis is one of the main concerns for 2nd generation ethanol production. The undissociated form of acetic acid can enter the cell by diffusion through the plasma membrane and trigger several toxic effects, such as uncoupling and lowered intracellular pH. The effect of acetic acid on the ethanol production was investigated in continuous cultivations by adding medium containing 2.5 to 20.0 g·L⁻¹ acetic acid at pH 5.0, at a dilution rate of 0.5 h⁻¹. The cultivations were performed at both high (~25 g·L⁻¹) and very high (100–200 g·L⁻¹) yeast concentration by retaining the yeast cells inside the reactor by a cross-flow membrane in a membrane bioreactor. The yeast was able to steadily produce ethanol from 25 g·L⁻¹ sucrose, at volumetric rates of 5–6 g·L⁻¹·h⁻¹ at acetic acid concentrations up to 15.0 g·L⁻¹. However, the yeast continued to produce ethanol also at a concentration of 20 g·L⁻¹ acetic acid but at a declining rate. The study thereby demonstrates the great potential of the membrane bioreactor for improving the robustness of the ethanol production based on lignocellulosic raw materials.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.