Analysis of methods for quantifying yeast cell concentration in complex lignocellulosic fermentation processes
Journal article, 2021

Cell mass and viability are tightly linked to the productivity of fermentation processes. In 2 generation lignocellulose-based media quantitative measurement of cell concentration is challenging because of particles, auto-fluorescence, and intrinsic colour and turbidity of the media. We systematically evaluated several methods for quantifying total and viable yeast cell concentrations to validate their use in lignocellulosic media. Several automated cell counting systems and stain-based viability tests had very limited applicability in such samples. In contrast, manual cell enumeration in a hemocytometer, plating and enumeration of colony forming units, qPCR, and in situ dielectric spectroscopy were further investigated. Parameter optimization to measurements in synthetic lignocellulosic media, which mimicked typical lignocellulosic fermentation conditions, resulted in statistically significant calibration models with good predictive capacity for these four methods. Manual enumeration of cells in a hemocytometer and of CFU were further validated for quantitative assessment of cell numbers in simultaneous saccharification and fermentation experiments on steam-exploded wheat straw. Furthermore, quantitative correlations could be established between these variables and in situ permittivity. In contrast, qPCR quantification suffered from inconsistent DNA extraction from the lignocellulosic slurries. Development of reliable and validated cell quantification methods and understanding their strengths and limitations in lignocellulosic contexts, will enable further development, optimization, and control of lignocellulose-based fermentation processes.

Author

Ruifei Wang

Nouryon

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Bettina Lorantfy

BioPhero ApS

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Salvatore Fusco

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Verona University

Lisbeth Olsson

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Carl Johan Franzén

Chalmers, Biology and Biological Engineering, Industrial Biotechnology

Scientific Reports

2045-2322 (ISSN)

Vol. 11 1 11293

Scale-Up: Multi-Feed SSF with integrated propagation of flocculating xylose-fermenting yeast

Swedish Energy Agency (P37353-1), 2013-08-01 -- 2015-06-30.

Areas of Advance

Nanoscience and Nanotechnology (SO 2010-2017, EI 2018-)

Subject Categories

Biomedical Laboratory Science/Technology

Biophysics

Other Industrial Biotechnology

DOI

10.1038/s41598-021-90703-8

PubMed

34050249

More information

Latest update

6/8/2021 2