VIEW ARTICLE    doi:10.1094/ASBCJ-2011-0408-01

Enzyme-aided Fractionation of Brewer’s Spent Grains in Pilot Scale. P. Forssell (1), VTT Technical Research Centre of Finland, VTT, Finland; J. Treimo and V. G. H. Eijsink, Norwegian University of Life Sciences, Department of Chemistry, Biotechnology and Food Science, Ås, Norway; C. B. Faulds and S. Collins, Institute of Food Research, Norwich, U.K.; H. A. Schols and S. W. A. Hinz, Wageningen Agricultural University, Laboratory of Food Chemistry, Wageningen, The Netherlands; O. Myllymäki and T. Tamminen, VTT Technical Research Centre of Finland, VTT, Finland; J. Zoldners, Latvian State Institute of Wood Chemistry, Riga, Latvia; K. Viljanen, VTT Technical Research Centre of Finland, VTT, Finland; K. W. Waldron, Institute of Food Research, Norwich, U.K.; and J. Buchert, VTT Technical Research Centre of Finland, VTT, Finland. (1) Corresponding author. E-mail: <pirkko.forssell@vtt.fi>; Phone: +358 20 722 5212; Fax: +358 20 722 7071. J. Am. Soc. Brew. Chem. 69(2):91-99, 2011.

Brewer’s spent grain (BSG) is an important coproduct of the brewing industry and is generally used in animal feed. Recently, there has been considerable research into the use of enzymes to convert BSG into more value-added products. In this study, the efficiency of enzymatic fractionation of freshly produced BSG was studied in pilot scale. Carbohydrate- and protein-degrading enzymes were applied sequentially to produce three fractions: carbohydrate hydrolysate, protein hydrolysate, and a solid lignin-carbohydrate residue. To minimize microbial contamination, processing was performed at 60°C for 4 hr. In all, 14 and 36% of the original dry matter was liberated by carbohydrase and protease, respectively. The carbohydrate-degrading enzyme cocktail produced cellulose- and hemicellulose-derived mono- and oligosaccharides. The protease treatment released peptide-enriched hydrolysate. Approximately half of the original BSG solids were solubilized during the two-stage enzymatic process. Although the protease efficiently released the majority of BSG proteins, the carbohydrate matrix was much less accessible to enzyme attack. The impact of scale-up to pilot scale was compared with previous laboratory-scale studies, and the results were found to be in good agreement. Keywords: Brewer’s spent grain, Fiber-degrading enzymes, Fractionation, Hydrolysis residue, Proteases

El grano gastado cervecero (BSG) por sus insignias en ingles) es un co-producto importante de la industria cervecera y se utiliza generalmente en la alimentación animal. Recientemente, ha habido una considerable investigación sobre el uso de enzimas para convertir BSG en más productos con valor agregado. En este estudio, la eficacia de fraccionamiento enzimático en el recién producido BSG se estudió en escala piloto. Las enzimas de degradación de hidratos de carbonos y proteínas se aplican de forma secuencial para producir tres fracciones: hidrolizado de hidratos de carbono, hidrolizado de proteína, y un residuo sólido de lignina en hidratos de carbono. Para reducir al mínimo la contaminación microbiana, el procesamiento se realizó a 60°C durante 4 hr. En total, 14 y 36% de la materia seca original fue liberado por carbohidrasa y la proteasa, respectivamente. El cóctel de enzimas de degradación de hidratos de carbono producido celulosa y hemicelulosa- derivados de mono y oligosacáridos. El tratamiento de la proteasa en libertad hidrolizado de péptido-enriquecido. Aproximadamente la mitad de la original sólidos BSG se solubiliza durante el proceso de dos etapas enzimáticas. A pesar de la proteasa en libertad de manera eficiente la mayoría de las proteínas BSG, la matriz de hidratos de carbono era mucho menos accesible a la enzima ataque. El impacto de la ampliación a escala piloto se comparó con estudios previos a escala de laboratorio, y los resultados se encontró que en buen acuerdo. Palabras claves: Enzimas de degradación de la fibra, Fraccionamiento, Grano gastado, Proteasas, Residuos de la hidrólisis