A novel xylanase, XynA4-2, from thermoacidophilic Alicyclobacillus sp. A4 with potential applications in the brewing industry

Abstract

A xylanase gene, xynA4-2, was obtained from the genome sequence of thermoacidophilic Alicyclobacillus sp. A4 and expressed in Escherichia coli BL21 (DE3). xynA4-2 encodes a mature protein of 411 residues with a calculated molecular weight of 46.8 kDa. Based on the amino acid sequence similarities (highest identity of 61%), the enzyme was confined into glycoside hydrolase family 10. The purified recombinant XynA4-2 exhibited maximum activity at pH 6.2 and 55°C. The enzyme was stable over a broad pH range, retaining more than 90% of the original activity at pH 5.8-12.0, 37°C for 1 h. The substrate specificity of XynA4-2 was relatively narrow, exhibiting 100, 93, and 35% of the relative activity towards birchwood xylan, oat spelt xylan, and wheat arabinoxylan, respectively. Supplementation of XynA4-2 to mash caused the reduction of mash filtration rate (5.6%) and viscosity (4.0%). When combined with the commercial glucanase from Sunson, higher reduction was detected in the filtration rate (12.0%) and viscosity (17.2%). These favorable properties make XynA4-2 a good candidate in the brewing industry.

Insight into Glycoside Hydrolases for Debranched Xylan Degradation from Extremely Thermophilic Bacterium Caldicellulosiruptor lactoaceticus

“…The presence of 1 mM Mn 2+ , β-ME and EDTA enhanced the Alicyclobacillus sp. A4 XynA4-2 activity, whereas 1 mM Zn 2+ , Cu 2+ , and SDS resulted in severe or complete inhibition [35]. Likewise, the activity of Actinomadura sp.…”

“…Similarly, the hydrolysis products of birchwood xylan by Alicyclobacillus sp. A4 XynA4-2 contained 92.7% xylose and 7.3% xylobiose [35] . However, xylotriose and xylotetraose instead of xylose were formed largely from the hydrolytic reaction of birchwood xylan by C. laeviribosi HY-21 iXylC [13] .…”

Microbial heterotrophic production in an oligotrophic acidic geothermal lake: responses to organic amendments and terrestrial plant litter

“…Alicyclobacillus sp. contain endoglucanases (Bai et al ., , b) and xylanases (Bai et al ., ; Wang et al ., ), as may some species of Sulfolobus (Girfoglio et al ., ). Most work has focused on fungal enzymes, some of these are quite acid‐ or thermal‐tolerant (Iefuji et al ., ; Kimura et al ., ; de Lemos Esteves et al ., ; Collins et al ., ; Viikari et al ., ; Zhang et al ., ), and include enzymes produced by taxa associated with geothermal or acid environments that we have found in BSL, such as Acidomyces or Phialophora .…”

Studies on the degradation pattern of wheat malt endo‐1,4‐β‐xylanase on wheat‐derived arabinoxylans

“…Arabinoxylan may be enzymatically cleaved during grain germination and beer brewing saccharification to produce xylose and arabinose to remain in the wort, but it is not utilized by the yeast and ultimately appears in the beer 5 . If arabinoxylan is not completely degraded during malting, the residual arabinoxylan, which can be highly displaced and attached to other compounds, will lead to filtration difficulties in the brewing process, high wort viscosity and ultimately clogging of filter membrane, and dark and cloudy beer 6,7 …”

“…5 If arabinoxylan is not completely degraded during malting, the residual arabinoxylan, which can be highly displaced and attached to other compounds, will lead to filtration difficulties in the brewing process, high wort viscosity and ultimately clogging of filter membrane, and dark and cloudy beer. 6,7 Xylanolytic enzymes are a group of enzymes consisting of ⊍-Larabinofuranosidase (EC 3.2.1.37), endo-1,4-⊎-xylanase (EC 3.2.1.8), ⊍-glucuronidase (EC 3.2.1.139), ⊎-1,4-xylosidase (EC 3.2.1.37) and so on. 8 Among them, endo-1,4-⊎-xylanase is the most important enzyme for the degradation of xylan, which breaks the ⊎- (1,4)glycoside bond between xyloses (Xyl) from the inside and changes the distribution of arabinose (Ara).…”