Continuous ethanol production via ultrasound-enhanced yeast sedimentation

Domingo-Félez, C. , Jankowska, K., Skiadas, I. V., Woodley, J. M. and Pinelo, M. (2023) Continuous ethanol production via ultrasound-enhanced yeast sedimentation. Food and Bioproducts Processing, 140, pp. 181-188. (doi: 10.1016/j.fbp.2023.06.002)

Abstract

Continuous glucose fermentation produces bioethanol at higher volumetric rates than conventional batch or fed-batch systems. The retention of yeast cells via ultrasonic sedimentation in a lab-scale fermenter allowed for shearless, continuous cell upconcentration, and consequently process intensification. The cell separation efficiency of the ultrasonic system was predicted with a Response Surface Model (RSM) developed for yeast cells based on the linear, mixed, and quadratic effects of the operating variables and flow rates (3 levels, 5 variables). The experiments for the RSM calibration were designed via a central composite design. The efficiency model was validated and showed dependency to the Biomass concentration, Power input, and Harvest rate (R2calibration = 0.92, R2prediction = 0.83). A lab-scale fermenter fed with yeast growth medium was operated at varying dilution rates (0.1 – 0.6 h−1) based on the RSM to maximize the cell retention efficiency (23%−90%). Yeast cell concentration in the fermenter reached up to 31.5 ± 0.7 g/L while it remained at around 3 g/L in the harvest stream for all the dilution rates tested. The ethanol concentration ranged between 17 and 23 g/L and reached high volumetric productivity (8.8 g/L/h). A control run without ultrasonic sedimentation led to the washout of biomass at a dilution rate of 0.6 h−1. Ultrasonic yeast sedimentation is a promising technology for cell retention and enhanced productivity in continuous fermentation processes.

• Item Type: Articles
• Additional Information: This work was funded by the Novo Nordisk Foundation within the framework of the Fermentation-based Biomanufacturing Initiative (FBM), grant number NNF17SA0031362.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Domingo-Felez, Dr Carlos
• Authors: Domingo-Félez, C., Jankowska, K., Skiadas, I. V., Woodley, J. M., and Pinelo, M.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• Journal Name: Food and Bioproducts Processing
• Publisher: Elsevier
• ISSN: 0960-3085
• ISSN (Online): 1744-3571
• Published Online: 09 June 2023
• Copyright Holders: Copyright © 2023 The Authors
• First Published: First published in Food and Bioproducts Processing 140: 181-188
• Publisher Policy: Reproduced under a Creative Commons License