Presenter: Matthew J. Farber, University of the Sciences,
Philadelphia, PA
Proteases are responsible for the cleavage and breakdown
of other proteins. Previous studies have demonstrated
that the yeast protease, proteinase A (PrA), also called
saccharopepsin, is secreted in beer during fermentation.
This protease hypothetically degrades foam-promoting
proteins, thus decreasing head retention of the beer. Because
the concentration of secreted PrA during fermentation has
been correlated with yeast viability and proper nutrition,
the precise measurement of PrA activity is important for
quality control. Previous assays to measure PrA activity have
demonstrated non-specificity, low sensitivity, and high cost.
Therefore, we have developed a novel, genetically encoded
PrA sensor using engineered antibodies that fluoresce after
cleavage by PrA. Using less than a drop of beer as the source
of PrA, we can measure PrA activity over time. Thus far, we
have demonstrated that mechanical disruption of yeast and
prolonged storage of yeast increases the activity of PrA. In the
future, we hope to use our PrA sensor to measure PrA activity
induced by variables such as different yeast strains, improper
handling of yeast, and prolonged back slopping. In addition,
our platform will allow us to develop sensors for additional
yeast proteases that might be relevant to the brewing industry.
Matthew Farber received a B.S. degree in biology from Seton
Hall University (South Orange, NJ) and a Ph.D. degree
in molecular and cellular biology from the University of
Pittsburgh (Pittsburgh, PA). He is currently a postdoctoral
fellow under Peter Berget at the University of the Sciences
(Philadelphia, PA), specializing in cell biology and protein
purification. Specifically, he engineers and produces biosensors
capable of measuring the activity of proteases. His interest in
brewing led him to apply these sensors to yeast targets relevant
to the brewing industry. In addition to research, Matt teaches a
graduate course in biotechnology and is currently developing
the curriculum for an undergraduate course on the molecular
biology of brewing.
