谷类秸秆接种瘤胃液的厌氧消化性能和三维荧光光谱特征

The Anaerobic Digestion Performance of Cereal Straw Inoculated With Rumen Fluid and Its Three-Dimensional Excitation Emission Matrix Fluorescence Spectroscopic Characteristics

在全自动甲烷潜力测试系统中,以瘤胃液为接种物,研究了谷类秸秆(水稻、小麦和高粱)的产酸产甲烷性能和三维荧光光谱特征。结果表明,奶牛瘤胃微生物对谷类秸秆表现出很强的水解酸化能力。经过5 d厌氧消化,水稻、小麦和高粱秸秆单位质量挥发性固体(VS)的总挥发性脂肪酸(TVFAs)产率分别达410. 9、430. 9和472. 0 mg·g-1。谷类秸秆的产甲烷规律符合改进型Gompertz模型。经过55 d的厌氧消化,水稻、小麦和高粱秸秆(以VS计)的甲烷产量分别为66. 29、103. 79和76. 89 m L·g-1。通过三维荧光光谱耦合平行因子分析(PARAFAC)识别溶解性有机物的3个有效荧光组分,3个组分分别为酪氨酸类物质、色氨酸类物质和低分子量腐殖酸类物质。其中,色氨酸类物质的荧光强度与TVFAs浓度呈幂函数关系。谷类秸秆溶解性有机物的腐殖化指数(HIX)经过5 d厌氧消化后降低,而后呈现逐渐上升趋势。

The performance of volatile fatty acids(VFAs)and methane production during anaerobic digestion of cereal straw(rice,wheat and sorghum straw)and its three-dimensional excitation emission matrix fluorescence spectroscopic characteristics were investigated in an automatic biochemical methane potential test system inoculated with rumen fluid.The results show that,rumen microorganism from dairy cattle owns strong hydrolysis and acidification ability for cereal straw.After 5 d of anaerobic digestion,the amount of total VFAs(TVFAs)for rice,wheat and sorghum straw were 410.9,430.9,and 472.0 mg·g^-1 volatile solids(VS),respectively.The modified Gompertz model fits well to methane producing profile of cereal straw.After 55d of operation,the corresponding methane yields were 66.29,103.79,and 76.89 mL·g^-1 VS,respectively.Three fluorescence components,i.e.,tyrosine-like,tryptophan-like and humic-like substances with low molecular weight,were identified in dissolved organic matter,using three-dimensional excitation emission matrix(EEM)fluorescence coupled with parallel factor analysis(PARAFAC).The relationship between fluorescence intensity of the tryptophan-like materials and TVFAs could be well expressed by a power function.The humidification index(HIX)of dissolved organic matter decreased after 5d and then increased gradually during anaerobic digestion.