Ma Zhuoming, Tang Jiafa, Li Shujun, Suo Enxiang
Key Laboratory of Bio-based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin, China.
Key Laboratory of Bio-based Material Science and Technology of Ministry of Education, Northeast Forestry University, Harbin, China.
Bioorg Chem. 2017 Dec;75:173-180. doi: 10.1016/j.bioorg.2017.09.014. Epub 2017 Sep 21.
Isolated by the cellulolytic enzyme lignin (CEL) process, water-alcohol (1:1, v/v) was introduced as co-solvent in the process of the hydrothermal treatment. The modification parameters such as reaction temperature and time, solid-to-liquid ratio, and catalysts (NaOH and NaOAlO) have been investigated in terms of the specific lignin properties, such as the phenolic hydroxyl content (OH), DPPH free radical scavenging rate, and formaldehyde value. The CELs were also characterized by GPC, FT-IR and H NMR spectroscopy, and Py-GC/MS. The key data are under optimal lignin modification conditions (solid-to-liquid ratio of 1:10 (w/v) and a temperature of 250°C for 60min) are: OH content: 2.50mmol/g; half maximal inhibitory concentration (IC) towards DPPH free radicals: 88.2mg/L; formaldehyde value: 446.9g/kg). Both base catalysts decrease the residue rate, but phenol reactivities of the products were also detracted. Py-GC/MS results revealed that modified lignin had a higher phenolic composition than the CEL did, especially the modified lignin without catalyst (ML), which represented 74.51% phenolic content.
通过纤维素分解酶木质素（CEL）工艺分离得到的水 - 醇（1:1，v/v）在水热处理过程中用作共溶剂。就特定的木质素性质，如酚羟基含量（OH）、DPPH自由基清除率和甲醛值而言，已经研究了反应温度和时间、固液比以及催化剂（NaOH和NaOAlO）等改性参数。还通过凝胶渗透色谱（GPC）、傅里叶变换红外光谱（FT - IR）、核磁共振氢谱（H NMR）以及热解气相色谱 - 质谱联用（Py - GC/MS）对CEL进行了表征。关键数据是在最佳木质素改性条件下（固液比为1:10（w/v），温度为250°C，时间为60分钟）得到的：OH含量：2.50mmol/g；对DPPH自由基的半数抑制浓度（IC）：88.2mg/L；甲醛值：446.9g/kg）。两种碱催化剂都降低了残渣率，但产物的酚反应性也有所降低。Py - GC/MS结果表明，改性木质素比CEL具有更高的酚类成分，尤其是无催化剂的改性木质素（ML），其酚类含量占74.51%。
