Mathibe Brian N, Malgas Samkelo, Radosavljevic Layla, Kumar Vishal, Shukla Pratyoosh, Pletschke Brett I
Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Grahamstown, 6140 Eastern Cape South Africa.
Enzyme Technology and Protein Bioinformatics Laboratory, Department of Microbiology, Maharshi Dayanand University, Rohtak, 124001 Haryana India.
3 Biotech. 2020 Aug;10(8):349. doi: 10.1007/s13205-020-02343-w. Epub 2020 Jul 22.
The inhibitory effect of eight model lignin derivatives (ferulic acid, guaiacol, kraft lignin (alkali, low sulfonate content), -coumaric acid, gallic acid, syringic acid, vanillin and vanillic acid) on XynA activity was evaluated. The model lignin derivatives viz. gallic acid, vanillic acid and vanillin were inhibitory to XynA activity, with an over 50% reduction in activity at concentrations as low as 0.5 mg/ml. However, enzyme deactivation studies in the absence of substrate showed that these pretreatment by-products do not interact with the enzyme except when in the presence of its substrate. The effect of the main structural properties of the pretreatment-derived phenolics, for example their hydroxyl and carbonyl group types, on XynA enzyme inhibition was investigated. The presence of carbonyl groups in phenolics appeared to confer stronger inhibitory effects than hydroxyl groups on XynA activity. The hydrolytic potential of XynA was not inhibited by a mixture of phenolics derived after steam pretreatment of woody biomass (Douglas fir and Black wattle). It appears as if the liquors from steam-pretreated woody biomass did not possess high enough phenolic content to confer XynA inhibition. The xylanase (XynA from ) is, therefore, a striking choice for application in biofuel and fine chemical industries for the xylan degradation in steam-pretreated biomass.
评估了八种木质素模型衍生物（阿魏酸、愈创木酚、硫酸盐木质素（碱性，低磺酸盐含量）、对香豆酸、没食子酸、丁香酸、香草醛和香草酸）对木聚糖酶A（XynA）活性的抑制作用。木质素模型衍生物中，没食子酸、香草酸和香草醛对XynA活性具有抑制作用，在低至0.5mg/ml的浓度下，活性降低超过50%。然而，在无底物情况下的酶失活研究表明，这些预处理副产物除了在底物存在时外，不会与酶相互作用。研究了预处理衍生酚类物质的主要结构特性，例如其羟基和羰基类型，对XynA酶抑制作用的影响。酚类物质中羰基的存在似乎比羟基对XynA活性具有更强的抑制作用。木质生物质（花旗松和黑荆树）蒸汽预处理后得到的酚类混合物并未抑制XynA的水解潜力。似乎蒸汽预处理木质生物质得到的液体中酚类含量不足以抑制XynA。因此，木聚糖酶（来自[具体来源未给出]的XynA）是生物燃料和精细化工行业中用于蒸汽预处理生物质中木聚糖降解的一个显著选择。
