Mandrich_2006_Appl.Environ.Microbiol_72_3191

Reference

Title : Alicyclobacillus acidocaldarius thermophilic esterase EST2's activity in milk and cheese models - Mandrich_2006_Appl.Environ.Microbiol_72_3191
Author(s) : Mandrich L , Manco G , Rossi M , Floris E , Jansen-van den Bosch T , Smit G , Wouters JA
Ref : Applied Environmental Microbiology , 72 :3191 , 2006
Abstract :

The aim of this work was to investigate the behavior of thermophilic esterase EST2 from Alicyclobacillus acidocaldarius in milk and cheese models. The pure enzyme was used to compare the EST2 hydrolytic activity to the activity of endogenous esterase EstA from Lactococcus lactis. The results indicate that EST2 exhibits 30-fold-higher esterase activity than EstA. As EstA has thioesterase activity, EST2 was assayed for this activity under the optimal conditions determined for EstA (namely, 30 degrees C and pH 7.5). Although it is a thermophilic enzyme, EST2 exhibited eightfold-higher thioesterase activity than EstA with S-methyl thiobutanoate. The abilities of EST2 and EstA to synthesize short-chain fatty acid esters were compared. Two methods were developed to do this. In the first method a spectrophotometric assay was used to monitor the synthesis of esters by the pure enzymes using p-nitrophenol as the alcohol substrate. The synthetic activities were also evaluated under conditions that mimicked those present in milk and/or cheese. The second method involved evaluation of the synthetic abilities of the enzymes when they were directly added to a model cheese matrix. Substantial ester synthesis by EST2 was observed under both conditions. Finally, esterase and thioesterase activities were evaluated in milk using the purified EST2 enzyme and in the model cheese matrix using a strain of L. lactis NZ9000 harboring the EST2 gene and thus overproducing EST2. Both the esterase and thioesterase activities measured in milk and in the cheese matrix were much greater than the activities of the controls.

PubMedSearch : Mandrich_2006_Appl.Environ.Microbiol_72_3191
PubMedID: 16672457
Gene_locus related to this paper: aliac-est2

Related information

Citations formats

Mandrich L, Manco G, Rossi M, Floris E, Jansen-van den Bosch T, Smit G, Wouters JA (2006)
Alicyclobacillus acidocaldarius thermophilic esterase EST2's activity in milk and cheese models
Applied Environmental Microbiology 72 :3191

Mandrich L, Manco G, Rossi M, Floris E, Jansen-van den Bosch T, Smit G, Wouters JA (2006)
Applied Environmental Microbiology 72 :3191