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

Abstract

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°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.

Brewers' spent grain: a review with an emphasis on food and health

“…Ktenioudaki et al (68), similarly found that, for BSG-containing wheat breads, the total phenolic content of the bound extracts did not vary between bread samples, although the total phenolic content of BSG flour was shown to be higher than that of wheat flour. FAE) by lactic acid bacteria (LAB) which could liberate free phenolic compounds from the BSG (70). This may be attributed to the production of certain enzymes (e.g.…”

Brewer's spent grain from different types of malt: Evaluation of the antioxidant activity and identification of the major phenolic compounds

“…In fact, the extraction technique is probably the most influential factor since BSG is a lignocellulosic material which contains significant amount of phenolic acids esterified to the cell-wall, making their recovery harder (Meneses et al, 2013;Moreira et al, 2012). Generally, the conventional extraction techniques, such as mechanical agitation solvent extraction, Soxhlet extraction, enzymatic and alkaline hydrolysis extractions (Dvorakova et al, 2008;Mussatto et al, 2007;Szwajgier, Waśko, Targoński, Niedźwiadek, & Bancarzewska, 2010), applied for the recovery of these compounds are time and solvent consuming, submitting polyphenols to thermal degradation and decreasing the phenolic content of the extracts. Furthermore, BSG phenolic extraction by MAE procedure may be more efficient in breaking ether and ester bonds of lignin to phenolic compounds, allowing a higher amount of these compounds, which explains the main difference between our results and those reported in the literature.…”

A novel application of microwave-assisted extraction of polyphenols from brewer’s spent grain with HPLC-DAD-MS analysis

“…The low-cost and large availability of BSG, associated with the current interest in the health benefits of phenolic acids, have stimulated the development of new processes for the extraction of the polyphenolic fraction from BSG [2]. Generally, the conventional extraction techniques for FA extraction are mechanical stirring [11], Soxhlet extraction [12], enzymatic [9,13] and alkaline extractions [3,10]. These extraction techniques are timing and solvent consuming, submitting polyphenols to thermal degradation and decreasing the antioxidant activity of the extracts due to the long extraction time used.…”