Cereals & Grains Association
Log In

In Vitro Fermentation of Xylooligosaccharides from Miscanthus x giganteus
M. H. CHEN (1), M. J. Bowman (2), B. S. Dien (2), M. A. Cotta (2), K. S. Swanson (1), T. R. Whitehead (3), G. C. Fahey (1), A. N. Beloshapka (1), L. B. Iten (2), L. L. Bauer (1), K. D. Rausch (1), M. E. Tumbleson (1), V. Singh (1). (1) University of Illinois at Urbana-Champaign, Urbana, IL, U.S.A.; (2) NCAUR, ARS, USDA, Peoria, IL, U.S.A.; (3) NCAUR, ARS, USDA, Urbana, IL, U.S.A.

<i>Miscanthus x giganteus</i> (MxG) is a perennial grass that has gained attention as a bioenergy crop; it is a leading candidate because it produces high biomass yields and has low input requirements. Previously, our group has demonstrated xylooligosaccharides (XOS) can be produced through autohydrolysis and recovered by carbon adsorption followed by ethanol elution. There is lack of information on the functionality of XOS from MxG and as a value added product for cellulosic ethanol. The object of this study was to perform <i>in vitro</i> fermentation of MxG XOS with <i>Bifidobacterium</i> spp. and human fecal culture to compare with commercial XOS products. Highly purified MxG XOS were cultured with beneficial bacteria <i>Bifidobacterium adolescentis</i> and <i>Bifidobacterium catenulatum</i>. Both <i>Bifidobacteria </i>were able to utilize MxG XOS as a carbon source for proliferation while <i>B. adolescentis</i> grew faster than <i>B. catenulatum</i> with specific growth rates of 0.69 to 0.33 (h-1). The substrate utilization was 84.1% by <i>B. adolescentis</i> and 76.9% by <i>B. catenulatum</i>. MxG XOS was further cultured with human fecal microbiota. Commercial XOS from Wako Ltd. and pectin were used as comparison. A pH drop was observed during fermentation from 7.1 to 5.0. Change in pH was similar for the MxG and Wako XOS cultures. MxG XOS produced 466.2 mg/g acetic acid, 74.6 mg/g propionic acid and 84.2 mg/g butyric acid; total SCFA was highest among the substrates. The beneficial bacteria <i>Bifidobacterium</i> spp. and <i>Lactobacillus</i> spp. population increased during the fermentation of MxG XOS. Compared with Wako XOS, MxG XOS had similar <i>Bifidobacterium</i> spp., <i>Lactobacillus</i> spp., <i>Escherichia coli</i> and <i>Clostridium perfringens</i> cell titers. The results substantiated MxG XOS as a prebiotic candidate could be utilized by <i>Bifidobacterium</i> spp. and fecal microbiota, be converted into beneficial metabolites and stimulate probiotics growth.

View Presentation