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79. The use of novel, fluorescent biosensors to measure Aspergillus niger prolyl endoprotease activity and substrates in beer over time

Matthew Farber (1); (1) University of the Sciences, Philadelphia, PA, U.S.A.


r prolyl endoprotease (ANPEP) is a proline-specific protease added by the brewer during fermentation to reduce chill haze and gluten content. Using technology developed in our lab, we have engineered fluorescent biosensors capable of measuring ANPEP activity in a single drop of beer. With this tool, we confirmed that ANPEP activity is stable over at least 6 months in commercial beer, with no negative effect on foam. To further examine the relationship between ANPEP and foam, we designed several biosensors based on the seven amino acids surrounding each proline residue in the foam-positive protein LTP-1. Surprisingly, many of the proline residues in LTP-1 are poor substrates. This data suggests that the amino acids surrounding the proline residue influence the substrate selectivity of ANPEP.

Matthew Farber is program director of the Brewing Science Certificate program and an assistant professor of biology at the University of the Sciences in Philadelphia, PA. He received a B.S. degree in biology from Seton Hall University and a Ph.D. degree in cellular and molecular biology from the University of Pittsburgh. His research focuses on innovative applications of biotechnology for the improvement of beer production. He is a member of the ASBC Innovation Committee, and he recently organized an ASBC LABS workshop on Yeast Quality.

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