Utility of Thermostable Xylanases of Mycothermus thermophilus in Generating Prebiotic Xylooligosaccharides

Abstract

Xylooligosaccharides as emerging prebiotics are able to promote the growth of probiotic bacteria. In the present study, four neutral, thermostable xylanases (MtXyn11A, MtXyn11At, MtXyn11B, and MtXyn11C) from compost fungus Mycothermus thermophilus CGMCC3.18119 were overexpressed in Pichia pastoris GS115 and used to produce xylooligosaccharides from beechwood xylan. The enzymes showed similar enzymatic properties (maximal activities at pH 6.0-6.5 and 65 °C) but varied in catalytic efficiency and cleaving actions. MtXyn11A, MtXyn11At, and MtXyn11C mainly produced xylobiose (59-62%), xylose (16-20%), and xylotriose (16-19%), while MtXyn11B released xylobiose (51%), xylotriose (32%), and xylose (12%) as the main products. When using the xylan hydrolysates of different xylanases as the carbon source, four probiotic Lactobacillus strains Lactobacillus brevis 1.2028, Lactobacillus rhamnosus GG, Lactobacillus casei BL23, and Lactobacillus plantarum WCSF1 were confirmed to use the xylooligosaccharides efficiently (83.8-98.2%), with L. brevis 1.2028 as the greatest.

Xylooligosaccharide Modulates Gut Microbiota and Alleviates Colonic Inflammation Caused by High Fat Diet Induced Obesity

“…Xylooligosaccharide (XOS) is a sugar oligomer of 2-7 xylose single molecules linked by β-1,4 (Jordan and Kurt, 2010), a hydrolysate of dietary fiber commonly found in corn stover, wheat bran and rice bran (Ma et al, 2017). XOS shows strong antioxidant and antibacterial activity in vitro (Gao et al, 2012).…”

Effect of extraction methods on the physicochemical, structural, functional, and antioxidant properties of the dietary fiber concentrates from male date palm flowers

“…The latter could be used in a large field of applications as XOs are stable over a wide range of pH and temperatures (Hsu et al, 2004; Lv et al, 2017). As a matter of fact, XOs could be used as prebiotics suggesting that they may be beneficial to gastrointestinal health and as a prevention from colon cancer when supplemented in diets (Hsu et al, 2004; Ma et al, 2017). In addition, due to their moderate sweetness, XOs are suitable as sweeteners and functional food ingredients (Lv et al, 2017).…”

Characterization of Two α-l-Arabinofuranosidases from Acetivibrio mesophilus and Their Synergistic Effect in Degradation of Arabinose-Containing Substrates

“…Arabinofuranosidases play an important role in the saccharification of arabinose-containing substrates, including arabinan and arabinoxylan. WAX-RS and WAX-I have almost the same Ara f /Xyl p ratio of 38:62 and 36:51, respectively, but WAX-I degradation is more difficult due to the presence of ferulic acid cross-links and the acetylation of xylose residues, whereas WAX-RS is extracted under alkaline conditions resulting in the removal of the ferulic acid residues [ 21 , 25 ]. Sugar beet arabinan as used in our study contains arabinofuranose residues attached to around 60% of O-3 positions of the α-1,5-linked arabinan backbone units and less frequently with α-1,2 arabinofuranose [ 36 ], while debranched arabinan exhibits a backbone with a very low degree of substitution.…”

“…Arabinoxylan (from wheat flour, insoluble; WAX-I), arabinoxylan (from wheat flour for the reducing sugar assay; WAX-RS), arabinan (from sugar beet pulp; SBA), debranched arabinan (from sugar beet pulp, arabinose:galactose:rhamnose = 71:26:3; DA), linear arabinan (from sugar beet pulp, arabinose: galactose:rhamnose:galacturonic acid = 85.2:7.6:1.5:5.7; LA), arabino-oligosaccharides (AOS), xylo-oligosaccharides (XOS) and arabino-xylo-oligosaccharides (AXOS) were purchased from Megazyme (Wicklow, Ireland), Beechwood xylan were purchased from SERVA Electrophoresis GmbH (Heidelberg, Germany). WAX-I had an Araf:Xylp ratio of 36:51 while still maintaining ferulic acid crosslinks during the process of substrate extraction, while WAX-RS had an Araf:Xylp ratio of 38:62 with diferulate bridges mostly broken due to alkaline treatment during substrate extraction [ 21 , 25 ]. All insoluble substrates used in this study were washed with Milli-Q water followed by centrifugation before starting the enzyme assay.…”