Cellobiose cb

C. saccharoperbutylacetonicum strain N1-4 (HMT) (DSM 14923) was obtained from the German Collection of Microorganisms (DSMZ, Leibniz, Germany). The microorganism was grown on a tryptone-yeast extract-acetate (TYA) medium under anaerobic conditions by the method of Al-Shorgani et al. (64 (link)) with either 4% (wt/vol) cellobiose (CB) (Sigma Chemical Co., St. Louis, MO) or 5% (wt/vol) brewer’s spent grain (BSG), kindly provided by Instituto Tecnológico Agrario de Castilla y León (ITACyL) Valladolid, Spain (34 (link)), as the sole carbon and energy source. Growth on each of the two carbon sources was performed in two biological repeats. C. saccharoperbutylacetonicum cell culture supernatant fluids were filtered through 0.2-μm sterile plastic filters (Thermo Fisher Scientific, Waltham, MA, USA) and concentrated 15-fold using a Vivaspin concentrator (30-kDa cutoff; Sartorius Stedim Biotech GmbH, Göttingen, Germany).

Bacteroides cellulosolvens ATCC 35603 was grown under anaerobic conditions essentially as described by Murray et al. [22 (link)] with either cellobiose (CB, Sigma Chem. Co. St. Louis, MO) or microcrystalline cellulose (MCC, Avicel, E. Merck, Darmstadt, Germany) as carbon and energy source. B. cellulosolvens cell lysates were prepared using PopCulture Reagent (Novagen Inc, Darmstadt, Germany), as described by Slutzki et al. [31 (link)].