Monitoring the physiological status of brewing yeast.

Recent collaborative work between Aber Instruments and Dr Hazel Davey in IBERS has led to development of a prototype instrument that uses a different range of frequencies for monitoring cells and extends the value of the information that can be obtained. This new device has been tested in laboratory conditions under a range of exogenously applied stress conditions and initial results indicate that more subtle changes in cell health can be detected by using the new instrument. Sub-lethally damaged or stressed yeast perform badly in the brewery production environment leading to slow fermentation or spoiled product. A robust screen for cell health is need by Aber Instruments’ customers and is a key aim of this project.

The student will review the existing literature on measurement of physiological statues of microorganisms and be centrally involved in planning experiments. Laboratory facilities and expertise within IBERS will enable the student to develop fitness screens using automated growth curve analysis to measure the length of lag phase (time between inoculation and cells beginning to divide) and growth rate. The student will also develop flow cytometric and microscopy based methods for comparison with radio frequency-based methods as these will additionally allow cell heterogeneity to be quantified.

Further practical work will take place at ABER Instruments where the student will receive training in how to use the commercial and prototype instruments, perform controls and analyse the resulting data. Via Aber Instruments, the student will be provided with access to SAB Miller’s pilot plant to test the instrument in a production environment. Brewery samples will be tested using the prototype instrument alongside the established beta dispersion instrument as this will allow the impact of multiple endogenous and exogenous stresses to be tested – this is of key importance in developing a method for real world application. Following fermentation of one batch of beer, yeast are harvested, stored and re-pitched into another fermentation. This process in repeated several times before the yeast is discarded. The quality of the yeast deteriorates as a consequence of repeated exposure to multiple stresses but the number of re-use cycles is currently based on the practice of the brewery rather than on assessing the quality of the yeast. The student will follow this process using Aber Instruments’ technology and correlate the rapid measurements obtained with more time-consuming, traditional methods such as methylene blue staining, emergence from lag phase and subsequent growth rate.

The prospective applicant should have a minimum of a 1st or good 2:1 in a relevant degree, and be available to take up the studentship by end of January 2016, or as soon as possible thereafter.
To apply, please submit the following to the Postgraduate Admissions Office (email [Email Address Removed] or address below)
1. A completed Postgraduate Application Form, plus two references submitted by the deadline. Application and reference forms may be downloaded from http://www.aber.ac.uk/en/postgrad/howtoapply
2. A completed KESS participant application form (put the reference number AU10011 in the top right hand box of the application form) and an up-to-date CV. KESS application forms are available to download at the link below.
http://www.aber.ac.uk/en/rbi/staff-students/knowledge-economy-skills-scholarships/
3. A PhD proposal of up to 1,000 words where you expand on your experience and interests and describe why you are a good candidate for this research studentship. Please refer to the Project Description.
Informal enquiries should be made to Hazel Davey at [Email Address Removed] or 01970 621829.
Quote Reference AU10011