Table of Contents
Journal of Fuels
Volume 2015, Article ID 369283, 13 pages
Research Article

Optimising the (Microwave) Hydrothermal Pretreatment of Brewers Spent Grains for Bioethanol Production

1Brewing Science Section, Division of Food Sciences, The University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
2SABMiller PLC, SABMiller House, Church Street West, Woking, Surrey GU21 6HS, UK

Received 13 July 2015; Accepted 20 October 2015

Academic Editor: Stamatios Kalligeros

Copyright © 2015 Stuart Wilkinson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


For the production of bioethanol from lignocellulosic biomass, it is important to optimise the thermochemical pretreatment which is required to facilitate subsequent liberation of monomeric sugars. Here, we report optimisation of pretreatment conditions for brewers spent grains (BSG) with the main objectives of (1) working at commercially relevant high solids content, (2) minimising energy and chemical inputs, and (3) maximising downstream sugar yields. Studies indicated there to be a play-off between pretreatment solids content, the usage of an acid catalyst, and pretreatment temperature. For example, yields of 80–90% theoretical glucose could be obtained following pretreatment at 35% w/v solids and 200°C, or at 140–160°C with addition of 1% HCl. However, at very high solids loadings (40–50% w/v) temperatures of 180–200°C were necessary to attain comparable sugar yields, even with an acid catalyst. The feasibility of producing bioethanol from feedstocks generated using these protocols was demonstrated (but not optimised) at laboratory scale.