Enzymatic Solubilization of Brewers’ Spent Grain by Combined Action of Carbohydrases and Peptidases

Abstract

Brewers' spent grain (BSG), a high-volume coproduct from the brewing industry, primarily contains proteins, barley cell wall carbohydrates, and lignin. To create new possibilities for the exploitation of this large biomass stream, the solubilization of BSG by the combined action of carbohydrases (Depol 740 and Econase) and peptidase (Alcalase and Promod 439) was explored. Hydrolysis protocols were optimized with respect to temperature (influencing both microbial contamination and rate of enzymatic hydrolysis), pH, enzyme dose, order of enzyme addition, and processing time. On the basis of this approach, one- and two-step protocols are proposed taking 4-8 h and yielding combined or separate fractions of hydrolyzed oligosaccharides and liberated hydrolyzed protein. Optimized procedures resulted in the solubilization of >80% of the proteinaceous material, up to 39% of the total carbohydrates, and up to 42% of total dry matter in BSG. Of the original xylan present in BSG, 36% could be solubilized. Sequential and simultaneous treatments with the two enzyme types gave similar results. In sequential processes, the order of the carbohydrase and peptidase treatments had only minor effects on the outcome. Depol 740 released more pentoses than Econase and gave slightly higher overall dry matter solubilization yields.

Brewers' spent grain; bioactivity of phenolic component, its role in animal nutrition and potential for incorporation in functional foods: a review

“…Both phenolic acids scavenge the reactive oxygen species and reactive nitrogen species, with concentration-dependent scavenging of NO, superoxide and 2,20-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid radical. In line with the previously discussed evidence, caffeic acid was a stronger scavenger of the DPPH radical, but ferulic acid was better (16) 0 . 7 --Robertson (21) 0 .…”

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

“…It was also stated that the crude enzyme preparations were able to release 2.5 times more ferulic acid than the pure forms of FAE from F. oxysporum and the xylanase from T. longibrachiatum M3 when acting together. BSG was also enzymatically solubilised by the carbohydrases and proteases produced by Trichoderma and Humicola enzyme preparations (protease-containing multienzyme mixtures) including different FAEs produced by both species 18,61 . Bartolome et al 5 studied the release of ferulic and p-coumaric acid from BSG by FAE and xylanase produced by Streptomyces avermitilis.…”

Improvement of functional and antimicrobial properties of brewery byproduct hydrolysed enzymatically

“…In recent years, increased incorporation of barley into the human diet is recommended (Newman, Lewis, Newman, Boik, & Ramage, 1989) due to nutraceutical properties. Brewer's spent grain (BSG), high-volume by-product from the brewing industry, primarily contains proteins, barley cell wall carbohydrates, and lignin (Treimo et al, 2009). However, to date its use has mainly been limited to animal feeding.…”