Xylooligosaccharides from Hardwood and Cereal Xylans Produced by a Thermostable Xylanase as Carbon Sources for Lactobacillus brevis and Bifidobacterium adolescentis

Abstract

To compare xylans from forestry with agricultural origins, hardwood xylan (birch) and cereal arabinoxylan (rye) were hydrolyzed using two variants of the xylanase RmXyn10A, full-length enzyme and catalytic module only, from Rhodothermus marinus . Cultivations of four selected bacterial species, using the xylooligosaccharide (XOS) containing hydrolysates as carbon source, showed selective growth of Lactobacillus brevis DSMZ 1264 and Bifidobacterium adolescentis ATCC 15703. Both strains were confirmed to utilize the XOS fraction (DP 2-5), whereas putative arabinoxylooligosaccharides from the rye arabinoxylan hydrolysate were utilized by only B. adolescentis. Escherichia coli did not grow, despite its capability to grow on the monosaccharides arabinose and xylose. It was also shown that Pediococcus parvulus strain 2.6 utilized neither xylose nor XOS for growth. In summary, RmXyn10A or its catalytic module proved suitable for high-temperature hydrolysis of hardwood xylan and cereal arabinoxylan, producing XOS that could qualify as prebiotics for use in functional food products.

Arabinoxylan Oligosaccharide Hydrolysis by Family 43 and 51 Glycosidases from Lactobacillus brevis DSM 20054

“…This fact has been shown to be of interest for lactic acid production from lignocellulosic biomass (37), especially because Lb. brevis is among the few LAB species known to efficiently utilize xylooligosaccharides, preferentially xylobiose (14,(20)(21)(22). Lb.…”

“…So far, Lb. brevis is the only Lactobacillus species reported to efficiently utilize XOS (14,(20)(21)(22), and a XOShydrolyzing ␤-xylosidase was recently isolated from Lb. brevis NCDC01 after the strain was grown on XOS (23).…”

Production of arabinoxylan-oligosaccharide mixtures of varying composition from rye bran by a combination of process conditions and type of xylanase

“…XOS stimulate some Lactobacillus and Bifidobacterium spp. (Crittenden et al, 2002;Falck et al, 2013), while AXOS stimulate mainly Bifidobacterium spp. (Falck et al, 2013;Pastell et al, 2009;Rivière et al, 2014).…”

Thermostable Glycoside Hydrolases in Biorefinery Technologies

“…This has resulted in trials, where thermoactive enzymes are run at conditions below their optimum temperature for activity, with lower specific activity, instead taking advantage of the increased stability of the enzyme-scaffold [49,50]. Other listed advantages (Fig.…”

“…For this purpose, endoxylanases are of interest, as xylooligosaccharides and arabinoxylooligosaccharides are shown to have a prebiotic potential, stimulating growth of probiotic bacteria (such as bifidobacteria) in the human gut. The thermostable endoxylanase RmXyn10A from Rhodothermus marinus [72], has for example proven useful for this purpose [49].…”