光谱学与光谱分析, 2018, 38 (7): 2086, 网络出版: 2018-07-24  

FTIR及SEM诊断铁铝锰氧化物参与微生物利用木质素形成矿物-菌体残留物的结构特征

Structural Characteristics of Mineral-Microbial Residues Formed by Microbial Utilization of Lignin Joined with Fe, Al, Mn-Oxides Based on FT-IR and SEM Techniques
作者单位
1 吉林农业科技学院农学院, 吉林 吉林 132101
2 吉林农业大学资源与环境学院, 吉林 长春 130118
3 土壤与农业可持续发展国家重点实验室/中国科学院南京土壤研究所, 江苏 南京 210008
摘要
铁铝锰氧化物催化木质素形成腐殖质具有重要作用。 为阐明微生物-木质素-铁铝锰氧化物三者间的关系, 揭示矿物-菌体残留物的结构特征, 采用液体摇瓶培养法, 以木质素为碳源, 通过添加针铁矿、 三羟铝石及δ-MnO2粉末, 在接种复合菌剂后启动110 d液体培养, 期间动态收集矿物-菌体残留物, 利用FTIR及SEM技术对其特性进行研究。 结果表明: 针铁矿呈松针状结构, 参与微生物利用木质素形成矿物-菌体残留物后表面附着了条状的暗色物质, 表观结构不规则, 但晶体结构并未改变。 菌体中多糖类物质与针铁矿游离羟基的阴离子发生交换作用, 芳香碳结构比例增加, 菌体在针铁矿表面堆积掩蔽了Fe—OH键以及(001)面的γ-OH键, Fe—OH发生质子化使Fe—O键振动频率增强; 三羟铝石表面结构疏松、 呈绒球状物质, 参与形成矿物-菌体残留物后, 缩聚作用明显、 疏松程度降低、 表面微孔结构减少。 氢键作用使矿物-菌体残留物的铝羟基振动频率下降, 即与AlOH相结合的O—H键极性减弱; 木质素引入使芳香碳结构比例增加, 随着培养进行, 其含量先下降, 而后再历经缩合; δ-MnO2表面颗粒粗糙, 以絮状或颗粒状团聚, 参与形成矿物-菌体残留物后, 颗粒团聚趋势明显、 堆积更加紧密、 表面结构更加光滑。 60 d培养期间, δ-MnO2结晶度受到菌体堆积以及氢键作用使O—H键的极性减弱, 而后层间水分子—OH含量增加对其产生了叠加效应, 使3 404~3 435 cm-1处吸收峰强度增加。 菌体中多糖类物质的羟基通过氢键、 化学力与δ-MnO2表面发生缔合, 所形成的矿物-菌体残留物芳香碳结构比例增加, 但Mn—O基团受到掩蔽; δ-MnO2的参与能够使矿物-菌体残留物产生更大数量的芳香碳结构, 为腐殖质形成提供更多的稳定性碳, 其次是针铁矿, 而三羟铝石则在培养30~60 d更有利于木质素的微生物降解。
Abstract
The Fe, Al, Mn oxides play an important role in the catalytic action of lignin being transformed into HS. In order to elucidate the relationship among the microorganism-lignin-Fe, Al, Mn oxides effectively and reveal the structural characteristics of mineral-microbial residues, the culture method of liquid shake flask was adopted in this article, the lignin serving as the C source, through the addition of goethite, bayerite and δ-MnO2 powder to start the liquid culture of 110 days after inoculating the multiple strains, and then the mineral-microbial residues were dynamically collected and their characteristics were studied by FT-IR and SEM techniques. The results were as follows: goethite had some pine needle structures, and the strips of dark materials were formed and attached to its surface after its participation into the formation of mineral-microbial residues from the microbial utilization of lignin. The apparent structures of goethite were irregular, but its crystal structure had not been changed. The polysaccharides from the multiple strains could exchange with the anions of free hydroxyl groups of goethite, and the proportion of aromatic C structures could be increased. The Fe—OH bond and γ-OH bond of (001) surface were masked due to the microbial thallus covered on the surface of goethite, and the vibration frequency of Fe—O bond was enhanced by the protonation of Fe—OH; The surface structure of bayerite was loose and resembled with the fluff sphere-like substances. After the participation of bayerite in the formation of mineral-microbial residues, its polycondensation effect was obvious, the loose degree was decreased, and the microcellular structure from its surface was reduced. The aluminum hydroxyl vibration frequency of mineral-microbial residues was decreased due to the hydrogen bonding effect, namely the polarity of O—H bond combined with AlOH was weakened. The introduction of lignin could enhance the proportion of aromatic C structure of mineral-microbial residues, but with the culture, its content was decreased first, and then was through the condensation; The surface of δ-MnO2 particles were rough, which could be aggregated in the flocculent or granular form. After the participation in the formation of mineral-microbial residues, the aggregation trend of particles was obvious, the stacking was more compact and its surface structure was more smooth. During the period of 60 days, the crystallinity from δ-MnO2 was affected by the superposition from the microbial thallus and hydrogen bonding, which could reduce the polarity of O—H bond. The increase of —OH content of H2O molecule in the interlayer could produce a superposition effect on the O—H bond, which could enhance the absorption peak intensity of 3 404~3 435 cm-1. The proportion of aromatic C structure of mineral-microbial residues was caused by the association of the hydroxyl groups from the polysaccharides of microbial thallus with the δ-MnO2 through the hydrogen bond and chemical force, but in the process the Mn—O group was masked. The participation of δ-MnO2 could make the mineral-microbial residues produce much more aromatic C structures and provide much more stable C contents for the formation of HS, followed by goethite, while the bayerite was beneficial to the microbial degradation of lignin during the culture of 30~60 d.

王帅, 徐俊平, 王楠, 雷琬莹, 范喜妍, 窦森. FTIR及SEM诊断铁铝锰氧化物参与微生物利用木质素形成矿物-菌体残留物的结构特征[J]. 光谱学与光谱分析, 2018, 38(7): 2086. WANG Shuai, XU Jun-ping, WANG Nan, LEI Wan-ying, FAN Xi-yan, DOU Sen. Structural Characteristics of Mineral-Microbial Residues Formed by Microbial Utilization of Lignin Joined with Fe, Al, Mn-Oxides Based on FT-IR and SEM Techniques[J]. Spectroscopy and Spectral Analysis, 2018, 38(7): 2086.

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