INRA-AgroParisTech, UMR 1091 Environnement et Grandes Cultures F-78850 Thiverval-Grignon, France.
Waste Manag. 2010 Dec;30(12):2448-60. doi: 10.1016/j.wasman.2010.06.021. Epub 2010 Jul 27.
Van Soest fractionation is widely employed to characterize exogenous organic matter. The soluble fraction of Van Soest fractionation (SOL, extracted using hot water and then neutral detergent) often increases in line with compost maturity, although it is generally considered as labile. We have developed an alternative extraction method that comprises four successive steps (extraction using hot water, sodium tetraborate, dichloromethane/methanol and chelating resin) in order to clarify the chemical nature of the SOL fraction and explain its biodegradability. This method was tested on municipal solid waste compost sampled during the thermophilic phase (MSWi) and after 8 months of composting (MSWm). Both methods extracted similar proportions of organic matter. The composition of the residues was similar in MSWm although differences were noted for the extraction of polysaccharides and lipids in the case of MSWi. The hot water extractable fraction decreased during composting. Its high biodegradability in MSWi was linked to the high polysaccharide content revealed by pyrolysis-GC/MS and FTIR spectroscopy. The increase in the sodium tetraborate extractable fraction mainly explained the increase in the SOL fraction during composting. This was made up of N-containing compounds, polysaccharides and lipids in the immature compost, and a majority of N-containing compounds in the mature compost. During composting, the stabilization of organic matter in the SOL fraction extractable by sodium tetraborate and EDTA might principally involve N-containing structures through the formation of complexes of organic matter with metal ions, especially Ca(2+), which may be broken down during extraction of the Van Soest soluble fraction. These mechanisms still need to be investigated.
范索特（Van Soest）分级法广泛用于描述外源性有机物。尽管范索特分级法中的可溶性部分（SOL，使用热水和中性洗涤剂提取）通常随着堆肥成熟度的增加而增加，但通常被认为是不稳定的。我们开发了一种替代提取方法，包括四个连续步骤（使用热水、四硼酸钠、二氯甲烷/甲醇和螯合树脂提取），以澄清 SOL 部分的化学性质并解释其可生物降解性。该方法在热相（MSWi）期间和堆肥 8 个月后（MSWm）采集的城市固体废物堆肥上进行了测试。两种方法都提取了相似比例的有机物。MSWm 中的残留物组成相似，但在 MSWi 中，多糖和脂质的提取存在差异。在堆肥过程中，热水可提取部分减少。其在 MSWi 中的高生物降解性与其通过热解 GC/MS 和傅里叶变换红外光谱揭示的高多糖含量有关。在堆肥过程中，四硼酸钠可提取部分的增加主要解释了 SOL 部分的增加。这由不成熟堆肥中的含氮化合物、多糖和脂质以及成熟堆肥中的大多数含氮化合物组成。在堆肥过程中，通过形成有机物与金属离子（特别是 Ca(2+)）的复合物，可能会在提取范索特可溶性部分时破坏稳定在可提取的四硼酸钠和 EDTA 的 SOL 部分中的有机物，从而可能会稳定在可提取的四硼酸钠和 EDTA 的 SOL 部分中的有机物。这些机制仍需要进一步研究。
