The Use of a Novel Ferulic Acid Esterase from Lactobacillus acidophilus K1 for the Release of Phenolic Acids from Brewer's Spent Grain

J. Inst. Brew. 116(3), 293-303, 2010 In this work, an extracellular ferulic acid esterase was produced in bioreactor cultivations of Lactobacillus acidophilus K1 strain. The enzyme was partially purified using ultrafiltration (10 kDa), dialysis (4-6 kDa) and Fast Protein Liquid Chromatography (Sepharose CM, Sephacryl S-300). A considerable increment of enzyme activity (31-fold) in the final preparation was achieved. Two distinct bands (approx. 21.5 kDa and 39 kDa) were obtained after SDS-PAGE. A high similarity of the purified enzyme (LC-MS/MS analysis) to tannase and ferulic acid esterase from Burkholderia ambifaria MEX-5 was obtained. The optimal pH and temperature for the enzyme activity were 6.3 and 37 degrees C, respectively. The enzyme preparation effectively released phenolic acids (mainly ferulic and p-coumaric acid) from brewer's spent grain. This novel enzyme preparation can be used for the utilisation of a valuable and inexpensive by-product of the brewing industry.