Biotechnological Potential of Brewers Spent Grain and its Recent Applications

Purpose Brewers spent grain (BSG) is a by-product of the brewing process corresponding to around 85% of total by-products generated. The great number of publications over the last 5 years, on the biotechnological applications of BSG, represents the increased scientific interest on it. This critical, state of the art review aims at gathering and analysing the most recent scientific efforts on the biotechnological potential of Brewer's spent grain and on its evaluation as a feedstock for high added value products. Methods The assiduous bibliographic retrospection focused on the latest scientific reports. The consideration of all relevant scientific articles was thorough and critical. The classification of the scientific efforts was made not only according to the end-products but also according to the biotechnological approach adopted. Results BSG has been used in a wide range of biotechnological applications such as substrate for enzymes production, as a source for value-added products (antioxidants, monosaccharides, oligosaccharides, xylitol, arabitol, bioethanol, biogas or lactic acid) or for the production of functional proteins and lipids. Its applications as a carrier in various bioprocesses have also been reported. Conclusion The implementation of BSG's fractionation in industrial scale seems to be the next step in BSG's exploitation. A fractionation process which allows the exploitation of biomolecules belonging to different classes, produced from one feedstock (BSG) may be used as a pattern for the implementation of the biorefinery concept in industrial scale, as long as the methods adopted ensure the functionality of the potentially valuable components.