Romero A M, Mateo J J, Maicas S
Departament de Microbiologia i Ecologia, Universitat de València, Burjassot, Spain.
Lett Appl Microbiol. 2012 Nov;55(5):354-61. doi: 10.1111/j.1472-765X.2012.03297.x. Epub 2012 Sep 7.
The purification and biochemical properties of the 1,4-β-xylosidase of an oenological yeast were investigated.
An ethanol-tolerant 1,4-β-xylosidase was purified from cultures of a strain of Pichia membranifaciens grown on xylan at 28°C. The enzyme was purified by sequential chromatography on DEAE cellulose and Sephadex G-100. The relative molecular mass of the enzyme was determined to be 50kDa by SDS-PAGE. The activity of 1,4-β-xylosidase was optimum at pH 6·0 and at 35°C. The activity had a Km of 0·48±0·06mmol l(-1) and a Vmax of 7·4±0·1μmol min(-1)mg(-1) protein for p-nitrophenyl-β-d-xylopyranoside.
The enzyme characteristics (pH and thermal stability, low inhibition rate by glucose and ethanol tolerance) make this enzyme a good candidate to be used in enzymatic production of xylose and improvement of hemicellulose saccharification for production of bioethanol.
This study may be useful for assessing the ability of the 1,4-β-xylosidase from P. membranifaciens to be used in the bioethanol production process.
研究一种酿酒酵母的1,4-β-木糖苷酶的纯化及生化特性。
从在28°C下以木聚糖为培养基培养的膜醭毕赤酵母菌株的培养物中纯化出一种耐乙醇的1,4-β-木糖苷酶。该酶通过先后在DEAE纤维素和葡聚糖G-100上进行层析纯化。通过SDS-PAGE测定该酶的相对分子质量为50kDa。1,4-β-木糖苷酶的活性在pH 6.0和35°C时最佳。对于对硝基苯基-β-D-吡喃木糖苷，该活性的Km为0.48±0.06mmol l(-1)，Vmax为7.4±0.1μmol min(-1)mg(-1)蛋白质。
该酶的特性（pH和热稳定性、葡萄糖抑制率低以及耐乙醇）使其成为用于木糖酶促生产以及改善半纤维素糖化以生产生物乙醇的良好候选酶。
本研究可能有助于评估膜醭毕赤酵母的1,4-β-木糖苷酶在生物乙醇生产过程中的应用能力。
