Hyperthermostable Thermotoga maritima xylanase XYN10B shows high activity at high temperatures in the presence of biomass-dissolving hydrophilic ionic liquids

Abstract

The gene of Thermotoga maritima GH10 xylanase (TmXYN10B) was synthesised to study the extreme limits of this hyperthermostable enzyme at high temperatures in the presence of biomass-dissolving hydrophilic ionic liquids (ILs). TmXYN10B expressed from Pichia pastoris showed maximal activity at 100 °C and retained 92 % of maximal activity at 105 °C in a 30-min assay. Although the temperature optimum of activity was lowered by 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc), TmXYN10B retained partial activity in 15–35 % hydrophilic ILs, even at 75–90 °C. TmXYN10B retained over 80 % of its activity at 90 °C in 15 % [EMIM]OAc and 15–25 % 1-ethyl-3-methylimidazolium dimethylphosphate ([EMIM]DMP) during 22-h reactions. [EMIM]OAc may rigidify the enzyme and lower Vmax. However, only minor changes in kinetic parameter Km showed that competitive inhibition by [EMIM]OAc of TmXYN10B is minimal. In conclusion, when extended enzymatic reactions under extreme conditions are required, TmXYN10B shows extraordinary potential.Electronic supplementary materialThe online version of this article (doi:10.1007/s00792-016-0841-y) contains supplementary material, which is available to authorized users.

Screening of glycoside hydrolases and ionic liquids for fibre modification

“…However, this enzyme has demonstrated its hydrolytic efficiency in the presence of IL at higher temperatures (80-100 ∘ C). 23 In previous studies and in this study, family GH10 xylanases were generally found to be more IL-tolerant compared with family GH11 enzymes. 35 Earlier findings with [EMIM]AcO suggest that the IL interferes with substrate binding in the active site and this competitive inhibition may be more pronounced with family GH11 xylanases.…”

“…Among the studied xylanases TmXYN10B was the most thermostable enzyme, but it was not the most IL‐tolerant one. However, this enzyme has demonstrated its hydrolytic efficiency in the presence of IL at higher temperatures (80–100 °C) …”

“…The TfXYN10A construct was obtained from ROAL Oy and produced in E.coli . TmXYN10A was kindly provided as a lyophilized culture supernatant from Hairong Xiong (South‐central University for Nationalities, College of Life Science, Wuhan, China) and DtXYN10B was produced in E.coli at Aalto University. The other enzymes were obtained from commercial sources or as pre‐commercial preparates from ROAL Ltd as indicated in Table .…”

“…5(A) and (B), respectively). Enzyme tolerance to ILs varied greatly, although the GH10 xylanases (TfXYN10A, TmXYN10B, GH10) showed generally higher IL tolerance 23,35 over the GH11 xylanases (DtXYN11B, GH11). 24 Among the studied enzymes TfXYN10A was the most IL-tolerant enzyme retaining 100% and 48% of relative activity (averaged) in the presence of 15% and 40% IL, respectively.…”

Microbial diversity of thermophiles with biomass deconstruction potential in a foliage‐rich hot spring

“…(Currie et al., ) are known for decomposing biomass at high temperatures (Bhalla, Bansal, Kumar, Bischoff, & Sani, ). Furthermore, members of the genera Thermotoga (Yu et al., ), Rhodothermus (Keshk, ), Anoxybacillus (Chan et al., ), Rhodothermaceae strain RA (Goh et al., ), and Caldicellulosiruptor (Peng et al., ) were found to produce thermostable enzymes for biomass saccharification.…”