Enzymatic production of wheat and ryegrass derived xylooligosaccharides and evaluation of their in vitro effect on pig gut microbiota

Gleb Dotsenko,Anne S. Meyer,Anders Thygesen,Michael Krogsgaard Nielsen,Lene Lange,Nuria Canibe

doi:10.1007/s13399-017-0298-y

Gleb Dotsenko, Anne S. Meyer + Show 4 more

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https://doi.org/10.1007/s13399-017-0298-y

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Abstract

This study examines enzymatic production of linear xylooligosaccharides (XOS) and branched arabinoxylooligosaccharides (AXOS) from monocotyledonous biomass, wheat straw and ryegrass, and compares the in vitro effects of these XOS and AXOS on pig gut microbiota. XOS and AXOS were obtained from the biomass by treatment with different endo-1,4-β-xylanases. XOS of DP2-6 from wheat straw, obtained after treatment with Aspergillus niger endo GH11, suppressed growth of Clostridium perfringens and resulted in a high level of lactic acid production when fermented in vitro by pig fecal microbiota. Analogously, XOS ryegrass produced in the same way also suppressed Cl. perfringens growth, and more so than the corresponding ryegrass AXOS, but AXOS exhibited a more pronounced stimulation of lactic acid bacteria growth than XOS. The prebiotic potential, i.e., suppression of Cl. perfringens and stimulation of lactic acid bacteria, for the ryegrass oligosaccharides was as follows: XOS, produced by A. niger endo-1,4-β-xylanase (GH 11) ≥ AXOS, produced by Thermotoga maritima and Cellvibrio mixtus endo-1,4-β-xylanase s (GH10) > AXOS, produced by Trichoderma viride and Aspergillus aculeatus endo-1,4-β-xylanase s (GH11). These results indicate that wheat straw as well as green grass biomass such as ryegrass have potential as new sources of putative prebiotics for pig feed.

Highlights

In the twenty-first century, utilization of renewable raw materials and efficient exploitation of their chemical and biological potential have gained increasing importance and priority in scientific research and industry
Hydrothermal pretreatment of RG at 100 °C (60 min) did not affect arabinoxylan branching, and arabinose content was found to be the same in non-treated and pretreated samples), but as assessed from the arabinose content, it was evident that increasing severity of the RG pretreatment resulted in gradual debranching of arabinoxylan accomplished by biomass enrichment in glucose and lignin (Table 1)
Hydrothermal pretreatment was shown to enable various degrees of arabinoxylan debranching depending on process temperature and duration

Summary

Introduction

In the twenty-first century, utilization of renewable raw materials and efficient exploitation of their chemical and biological potential have gained increasing importance and priority in scientific research and industry. In Europe, green and yellow biomass, e.g., fresh plant leaves. AXOS and XOS are pentose oligomers derived from arabinoxylans by physico-chemical or/and enzymatic treatments [8, 9]. It is noteworthy that these compounds can Biomass Conv. Enzymatic production of AXOS and XOS can benefit from the exquisite selectivity of enzymes in relation to discrimination on substrate degradation, principally allowing specific desirable products to be produced. Such enzymatic processing seems to be more economically and environmentally feasible than physico-chemical processing approaches. GH10 endo-1,4-β-xylanases are generally considered better than GH11 endo-1,4-β-xylanases for catalyzing cleavage of glycosidic linkages near arabinose-substituents. GH10 endo-1,4-β-xylanases are supposed to be able to produce shorter AXOS with higher yield than GH11 endo-1,4-β-xylanases

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