Predicting fermentation success in Saccharomyces cerevisiae
Lead Research Organisation:
Aberystwyth University
Department Name: IBERS
Abstract
Advances in technology has led to the modernisation of the brewing industry, always aiming to save money, time and to produce a high quality product is the key to success, Harsher processes such as high gravity brewing at specific gravities exceeding 1.080 yield high quantities at high alcohol by volume percentage (ABV%) however this causes stress to the yeast. Stresses to common brewing strains such as Saccharomyces cerevisiae renders yeast 'unable' to cope in such conditions leading to poor fermentation and waste batches due to the release of undesirable flavour compounds. The ability to predict the outcome of fermentation depending on the quality of yeast is a perspective within the industry that could prevent bad batches and identify stressors to the yeast rendering them incapable.
Traditional microbiological methods show advantages and disadvantages when determining viability. Microscopy and culturing methods cannot provide any indication of the vitality of the yeast cells which is the determination of physiological capabilities of the cell to categorise the health of the cell. The use of rapid measurement within an off-line atmosphere has high potential in the brewing industry. Rapid measurements rely on the physical and chemical abilities of the yeast cell rather than solely biological methods as this can be restrictive. Firstly, it must be taken into consideration that the use of such methods relies on the plasma membrane of the yeast to be intact. Leaky cells cannot be detected however and under stress conditions these cells usually perish.
Measurement using the following methods could be used in industry and compared to standardised control allowing the ability to predict
the fermentative outcome of yeast prior to pitching or during fermentation:
* Flow cytometry
* Fluorescence-activated cell sorting (FACS)
* Dielectric Spectroscopy
A standardised control could be generated by testing yeast suspensions during various health stages within the laboratory by inducing stress factors. This would give an understanding of how stress factors would affect the yeast within industry. By gaining specific figure of yeast health applicable to each method of testing would allow a quick method to determine the outcome of fermentation and whether yeast cells will undergo resuscitation or degradation. The application of this could save money within the industry and the rapid measurements could save time ultimately leading to further modernisation.
Traditional microbiological methods show advantages and disadvantages when determining viability. Microscopy and culturing methods cannot provide any indication of the vitality of the yeast cells which is the determination of physiological capabilities of the cell to categorise the health of the cell. The use of rapid measurement within an off-line atmosphere has high potential in the brewing industry. Rapid measurements rely on the physical and chemical abilities of the yeast cell rather than solely biological methods as this can be restrictive. Firstly, it must be taken into consideration that the use of such methods relies on the plasma membrane of the yeast to be intact. Leaky cells cannot be detected however and under stress conditions these cells usually perish.
Measurement using the following methods could be used in industry and compared to standardised control allowing the ability to predict
the fermentative outcome of yeast prior to pitching or during fermentation:
* Flow cytometry
* Fluorescence-activated cell sorting (FACS)
* Dielectric Spectroscopy
A standardised control could be generated by testing yeast suspensions during various health stages within the laboratory by inducing stress factors. This would give an understanding of how stress factors would affect the yeast within industry. By gaining specific figure of yeast health applicable to each method of testing would allow a quick method to determine the outcome of fermentation and whether yeast cells will undergo resuscitation or degradation. The application of this could save money within the industry and the rapid measurements could save time ultimately leading to further modernisation.
People |
ORCID iD |
| Hazel Davey (Primary Supervisor) | |
| Lindsey Male (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| BB/M015041/1 | 01/10/2015 | 30/09/2019 | |||
| 1645887 | Studentship | BB/M015041/1 | 01/10/2015 | 29/09/2019 | Lindsey Male |
| Description | Through the development of thesis chapters I have carried out research into various topics. Firstly, in an attempt to better understand current practices within the brewing sector a survey was issued to UK brewers. The responses to this survey have helped me to tailor my research to current techniques used rather than dated methods with are so often mentioned in literature. In another chapter I investigated the serial re-pitching of brewers yeast using acid washing and following the fermentation's closely using dielectric spectroscopy. Dielectric spectroscopy is a method of measuring biomass which the technology has been supplied by my industrial partner Aber Instruments. I have performed experiments in a attempt to understand the measurements taken at a cellular level and have found that capacitance measurements can show changes at a cellular level such at catabolite depletion. Work is still ongoing and I aim to develop my understanding on this further. I have successfully created a predictive model that can predict the suitability of a propagated yeast strain to determine its suitability for pitching. This is the first type of predictive model that aims to predict a measure of 'vitality'. |
| Exploitation Route | The results from my work with dielectric spectroscopy are being used by Aber Instruments to present in conferences. This chapter is also being developed for publication by myself and both my supervisors at Aberystwyth University. My work has also led to the development of ideas that could be potentially integrated into current products or lead to the development of new commercial products. |
| Sectors | Agriculture, Food and Drink,Manufacturing, including Industrial Biotechology |
| Description | My results from the chapter titled 'Using dielectric spectroscopy to visualise changes to the yeast population during fermentation' are being used by my industrial partner to present at an upcoming conference (Brewing Summit). It is unclear how these results will be utilised within the company at the present time. The predictive modelling results are also going to be represented at a conference on behalf of the company. |
| First Year Of Impact | 2017 |
| Sector | Digital/Communication/Information Technologies (including Software),Manufacturing, including Industrial Biotechology |