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Yeast Concentration & Viability

Cellometer offers solutions for yeast concentration or concentration and viability for a variety of sample conditions, depending on your needs.

Pure yeast cultures, concentration

Pure yeast cultures, concentration and viability (e.g. ethanol fermentation for beer, wine and other alcoholic beverages)

Heterogeneous yeast cultures (e.g. corn mash and sugar cane)

Yeast Concentration of Pure Cultures

Concentrations of pure yeast cultures are typically performed using brightfield imaging. Unlike most other image-based cell counters on the market, Cellometer instruments can be configured to accurately count cell types, down to 1 micron in size, such as yeast. Cellometer software can also handle various yeast morphologies to give accurate counts.

Single-celled yeast

Budding yeast

Chain-forming yeast

Brightfield cell concentration measurements have been validated using Cellometer.

For more information, download the application note Yeast Concentration and Viability using
Image-Based Fluorescence Analysis

Basic Requirements: Cellometer System for Yeast Concentration
Instrument	Cellometer Vision, 10x Magnification Cellometer Auto X4, 10x Magnification Cellometer Auto M10
Counting Chambers	PD100 SD100

Count & Viability for Brewery Fermentation

Cellometer System for Single Fluorescence Yeast Concentration & Viability
Instrument	Cellometer Vision, 10x Magnification Cellometer Auto X4, 10x Magnification
Counting Chambers	PD100 SD100

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Cellometer Vision incorporates image-based cell counting and fluorescence detection in a compact and easy-to-use instrument for generating yeast count and viability measurements. By providing more consistent results with less effort than manual methods, Cellometer Vision is ideal for use in fermentation processes in the brewing and bio fuel industries.

While a variety of methods exist to assess yeast viability, each one has specific drawbacks that make it less than ideal for use in a production environment requiring consistent and accurate results. Although culture-based methods can be used to determine yeast viability, staining techniques and direct observation are more commonly used in fermentation processes. The most widely used stain in the brewing industry, for example, is methylene blue. Live cells exclude or reduce the dye while dead cells stain blue. Manual counting of both live and dead cells on a hemacytometer is performed under a microscope to determine concentration and viability, but is a time-consuming and labor intensive process. More importantly, the methylene blue assay has been reported to produce inconsistent results and analysis can be subjective. Errors in cell counting, viability measurements, and data recording ultimately lead to inconsistent fermentation performance.

Use of the fluorescent dye oxonol (bis-(1,3-dibutylbarbituric acid)trimethine oxonol(DiBAC4(3)), an anionic membrane potential dye that preferentially stains dead cells, has been reported as a reliable and accurate method to assess yeast viability. Cellometer Vision automatically counts total and oxonol positive dead yeast cells addressing the need for simple, rapid counting and viability testing of yeast cells. By capturing both brightfield and fluorescent images from the same sample, the software determines total cell count and concentration and determines viability, typically in less than 60 seconds.

Method

Running Assay:

Results

Total counted yeast cells are indicated on-screen by green circles in the brightfield image (Figure 1). Dead cells stained with oxonol are indicated as fluorescent positive green circles in the fluorescent image (Figure 2). Cellometer software automatically calculates cell count, concentration, mean cell size, and viability and displays results. Cell size distribution histograms (Figure 6), data files, and cell images can be instantly created, and saved for further analysis or for quality control record keeping.

Figure 1. Total counted yeast cells are indicated on-screen by green circles

Figure 2. Fluorescent image showing oxonol stained dead cells (green circles), and live cells (red circles)

Yeast Type	Viability %
A	88.5
B	89.5
C	73.2
D	78.7
E	77.6
F	5.1

	Viability	Concentration	Mean Size
Yeast type E sample 1
Mean(n=6)	99.6	9.14X106	4.9
CV	0.2%	5.4%	2.4%
Yeast type E sample 2
Mean(n=7)	85.3	5.92X106	5.4
CV	4.1%	13.3%	1.7%
Yeast type E sample 3
Mean(n=7)	79.6	1.2X107	5.4
CV	4.2%	8.8%	1.8%

Count & Viability in Corn Mash Fermentation

Cellometer Vision System for Dual Fluorescence Yeast Concentration & Viability
Instrument	Cellometer Vision, 10x Magnification
Optics Modules	535-401 660-501
Counting Chambers	PD100 SD100
Reagent Kit	Cellometer ViaStain™ Kit for Live/Dead Yeast Concentration Including Stainer Buffer, Fluorescent Dye Mixture

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In research and development in the biofuel industry, selection of yeast strains (for higher ethanol tolerance) and fermentation conditions (yeast concentration, temperature, pH, nutrients, etc.) can be studied to optimize fermentation performance. Yeast viability measurement is needed to identify higher ethanol-tolerant yeast strains, which may prolong the fermentation cycle and increase biofuel output. In addition, yeast concentration may be optimized to improve fermentation performance. Cellometer uses an imaging cytometry method for concentration and viability measurements of yeast in corn mash.

How Does Yeast Count & Viability by Dual Fluorescence Work?

Video: Yeast Cell Concentration & Viability in Corn Mash
Cellometer Vision is a line of simple to use, automated cell analyzers with diverse functions. It combines bright field microscopy and multi-channel fluorescence images to generate cell count and fluorescence data. This video demonstration features the Cellometer Vision to measure yeast cell concentration and viability in a highly viscous corn mash sample. Watch video.

Technical Resources & Publications

Cell Counting Essentials View our mini presentation on Automated Yeast Counting and Viability Using Cellometer.

Publication Journal of Industrial Microbiology & Biotechnology,
October 2010
Direct concentration and viability measurement of yeast in corn mash using a novel imaging cytometry method.

Application Note Yeast Concentration and Viability using Image-Based Fluorescence Analysis

Application Note Counting Yeast, Human Platelet, and Algae Using Cellometer Auto M10

Application Note Simple, Fast and Consistent Determination of Yeast Viability using Oxonol

Poster Concentration and Viability Measurement of Yeast in Corn Mash using the Cellometer® Vision

Article Keeping an Eye On Yeast Cellometer is featured in the October 2010 issue of Ethanol Producer Magazine

Automated Yeast Counting & Viability Automated Yeast Counting & Viability for Brewing. Accurate & Efficient Yeast Fermentation Monitoring

Request a Demo One of our Applications Specialists can provide a 20-30 minute online demo or arrange a live demo in your lab.

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