Tag: yeast fermentation
The start of the Fall Semester and the 2015-16 school year brings with it a new start in the biology programs at McMurry. New Biomedical Science majors join those from Biology and Life Sciences in taking the new Biology Core – common classes that insure a common experience covering the breadth of biology. This fall, the first new course is being taught – General Biology I – and its follow-up (ingeniously called General Biology II) will follow in the spring.
Lots of schools have a similar two-semester freshman biology sequence. Like many, ours is cells, processes and genetics in the first and multicellular organisms, diversity of life and ecology in the second. However, we hope that the lab for General Biology I will set our program apart from most. The lab, designed by Dr. Benoit, is based on a few “canned” labs interspersed among several multi-week projects covering key concepts and teaching skills central to future biology courses. There will be a project creating and studying Winogradsky columns that will emphasize metabolism and nutrient cycling and ecological succession. Another will use yeast to demonstrate carbon dioxide generation in fermentation and alginate beads to follow its consumption in photosynthesis. A third will require groups of students to design experiments with yeast to study fermentation changes with variations in substrates or environmental conditions. And mitosis and meiosis will be followed using yeast mating experiments. Not exactly an approach taken by most colleges for teaching first semester college students. Our intent is to give them an engaging course unlike anything taken before, one that teaches principles and how science is done and provides experience putting skills learned into action to provide answers to biological questions.
We should be posting stories from this course here and on our Facebook page (https://www.facebook.com/pages/McMurry-Biomedical-Science-Program-BIMS/118598184311) during the semester. Hope you will follow our journey!
Senior BIMS major Luke Burcham has a fascination with fermentation. As an amateur brewmaster, his interest in the physiology of yeast fermentation has resulted in his choice for “life after McMurry”. He will be entering a graduate program at UC-Davis in January to study all things related to fermentation and brewing. From Borger TX to Davis CA is quite a move, but Luke is ready for the adventure.
With that in mind, Luke worked with Dr. Tom Benoit this semester to design a project that would give him a head-start on his graduate studies. After Luke reviewed some literature on the subject, he began to envision a project to investigate the impact of modifying the ion content of the growth medium for beer production to determine the best formulation. The experimental design began with a question on how calcium levels in the water used for the process might influence the physiology of the yeast in the batch. Could it be that increasing calcium ion content altered the growth characteristics of the yeast and alcohol content of the product? Would hard water result in a fundamentally different product than that produced in soft or distilled water?
Notes from research meetings and designs for experiments decorate the white board in the senior research lab (shown above). The final design Dr. Benoit and Luke settled on centered on using production of cell clumps and measurement of alcohol content as ways of monitoring physiological differences between batches. As yeast grow in a broth culture, they can form clumps of cells that fall out of suspension as nutrients are exhausted and the growth period comes to a close. This flocculation of yeast cells and cell debris is a necessary step to move from the cloudy active culture to a clear final (and commercially appealing) product. Could calcium concentration alter the dynamics of growth and flocculation?
After completing a variety of experiments this spring, the answer seems to be “yes”. Luke tells me that batches made with distilled/RO water averaged clumps of 17 cells (as measured microscopically using a hemacytometer), while batches made with added calcium chloride averaged clumps of 55 cells. In addition to having larger clumps, calcium enriched batches also produced less alcohol (as measured using a hydrometer). Luke is currently in the analysis process – explaining why clumps are larger and why larger clumps mean less alcohol produced – as he takes these findings and turns them into the final project poster for his capstone experience.
Luke’s project is a great example of the flexibility we provide our students to pursue senior projects in line with their interests and future plans. Luke’s future seems destined to be quite different from the one envisioned when he began his college life as a Biomedical Science major intent on dental school. However, the knowledge and skills and abilities gained in the BIMS program have application to his future and have equipped him well to succeed in his graduate work at UC-Davis.