Mechanism and characteristics of nature inspired enzyme-fungi synergistic system for lignin pretreatment

doi:10.16085/j.issn.1000-6613.2021-0642

Abstract

Abstract:

The natural termite-fungi symbiosis system can effectively convert lignocellulosic biomass. Its essence is the destruction of physical structure, modification of functional groups and the reduction of non-productive adsorption of lignin to enzymes, thereby improving the efficiency of enzymatic saccharification, which can provide new opportunities for the utilization of biomass energy. Based on laccase (La) that degrades lignin phenolic units in the termite guts and Termitomyces sp. (Te) that degrades lignocellulose in the nests, this study proposed a new system for synergistically pretreating lignin. The pretreatment characteristics of La and typical lignin-degrading fungi Phanerochaete chrysosporium (PC) on the lignin model compound-alkali lignin was compared with Te. The results showed that the maximum activities of laccase and lignin peroxidase (LiP) produced by Te were increased by 43.3% and 58.5%, respectively, after the alkali lignin was pretreated by laccase. Meanwhile, the maximum activities of laccase and manganese peroxidase (MnP) produced by PC were increased by 35.9% and 31.6%, respectively. Laccase pretreatment enhanced the properties of Te and PC on functional groups modification and the physical structures destruction of alkali lignin. The results of fourier infrared transform spectroscopy (FTIR) showed that the absorption peaks of alkali lignin functional groups were significantly reduced after enzyme-fungi synergistic system pretreatment. The results of scanning electron microscopy (SEM) and mercury injection test showed that enzyme-fungi synergistic system severely damaged the surface structure of alkali lignin, and the average pore size of alkali lignin pretreated by La and Te synergistic (La+Te) system was significantly increased by 31.1% and 45.6% compared with single La and single Te, respectively. The maximum enzyme adsorption capacity of alkali lignin pretreated by La+Te system was 51.5% less than that of untreated alkali lignin sample. Due to the significant reduction of non-productive adsorption, the subsequent enzymatic hydrolysis conversion rate was 71.5% higher than that of untreated alkali lignin sample. This study demonstrated enzyme-fungi synergistic system was effective in altering the physical and chemical properties of alkali lignin, thereby promoting subsequent enzymatic saccharification of cellulose, which may provide guidance for biofuel production.

Key words: process bionics, enzyme, Phanerochaete chrysosporium, Termitomyces sp., lignin, degradation, bioenergy

摘要：

白蚁-真菌自然共生体系可有效转化木质纤维素类生物质，其本质在于对木质素物理结构的破坏和官能团的修饰，减少木质素对酶的非生产性吸附，从而提升酶解糖化效率，为生物质高效能源化利用提供新思路。本文基于白蚁肠道中存在的分解木质素酚类单元的漆酶（La）和蚁巢内降解木质纤维素的蚁巢伞菌（Te），构建La和Te协同预处理木质素体系，比较La和典型的木质素降解菌黄孢原毛平革菌（PC）对木质素模型化合物碱木素的预处理特性。结果表明，在降解La预处理的碱木素过程中，Te产生的漆酶（La）和木质素过氧化物酶（LiP）活性最大值较未处理的碱木素样品分别提升43.3%、58.5%，PC产生的漆酶（La）和锰过氧化物酶（MnP）活性最大值较未处理的碱木素样品分别提升35.9%、31.6%。漆酶预处理强化了Te、PC对碱木素官能团的修饰和物理结构的破坏。傅里叶红外转换光谱分析（FTIR）表明酶菌协同体系处理后碱木素特征官能团的吸收峰显著降低。扫描电镜（SEM）和压汞测试结果表明酶菌协同体系对碱木素表面结构破坏严重，La和Te协同（La+Te）体系预处理后的碱木素平均孔径比单一La和单一Te分别显著提升31.1%、45.6%。经La+Te体系预处理后的碱木素最大酶吸附量较未处理的碱木素减少了51.5%，由于非生产性吸附显著减少，后续纤维素酶的转化率较未处理的碱木素样品提高了71.5%。本文证明了通过漆酶与真菌协同作用可有效改变碱木素物化特性，从而有效促进后续纤维素的酶解糖化，为木质纤维素类生物质高效利用提供指导。

关键词: 过程仿生, 酶, 黄孢原毛平革菌, 蚁巢伞菌, 木质素, 降解, 生物能源

CLC Number:

TQ353

TANG Liang, LIAO Qiang, XIA Ao, HUANG Yun, ZHU Xianqing, ZHU Xun. Mechanism and characteristics of nature inspired enzyme-fungi synergistic system for lignin pretreatment[J]. Chemical Industry and Engineering Progress, 2021, 40(10): 5378-5387.

唐亮, 廖强, 夏奡, 黄云, 朱贤青, 朱恂. 仿生酶菌协同体系预处理木质素机理及特性[J]. 化工进展, 2021, 40(10): 5378-5387.

Figures/Tables 14

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波数/cm^-1	标记
3222	O—H键拉伸振动
2935	CH₂，CH₃和CH₃O基团的C—H拉伸振动
1213	苯酚的C—O拉伸振动
1125	紫丁香基木素C—H面内变形
1081	醇类C—O拉伸振动

波数/cm^-1	标记
3222	O—H键拉伸振动
2935	CH₂，CH₃和CH₃O基团的C—H拉伸振动
1213	苯酚的C—O拉伸振动
1125	紫丁香基木素C—H面内变形
1081	醇类C—O拉伸振动

样品	平均孔径/nm	总孔容/mL?g^-1
未经处理	841.41	1.80
La处理	1250.72	1.76
PC处理	1000.64	1.44
La+PC处理	1796.31	1.45
Te处理	1125.92	1.44
La+Te处理	1639.46	1.67

样品	平均孔径/nm	总孔容/mL?g^-1
未经处理	841.41	1.80
La处理	1250.72	1.76
PC处理	1000.64	1.44
La+PC处理	1796.31	1.45
Te处理	1125.92	1.44
La+Te处理	1639.46	1.67

信号	δC/δH	标记
Bβ	54.15/3.07	树脂醇β—β键的C_β—H_β
-OMe	56.15/3.77	甲氧基的C—H
Aγ	60.71/3.43	β-O-4'亚结构的C_γ—H_γ
Bγ	71.57/3.76~4.16	树脂醇β-β键的C_γ—H_γ
Aα	71.64/4.78	β-O-4'亚结构的C_α—H_α
Aβ	84.81/4.29	与紫丁香基木素相连的β-O-4'亚结构的C_β—H_β
Bα	85.60/4.63	树脂醇β-β键的C_α—H_α
Cα	87.49/5.49	苯基香豆满亚结构β-5键的C_α—H_α
G2	111.05/6.91	愈创木基木素的C₂—H₂
G5	115.78/6.68	愈创木基木素的C₅—H₅
G6	119.32/6.76	愈创木基木素的C₆—H₆
H2，6	126.55/7.42	对羟基苯基木素的C_2，6—H_2，6