Institute of Chemistry of São Carlos, University of São Paulo, CP - 780, São Carlos, São Paulo, CEP 13560-970, Brazil.
Department of Neuroscience, School of Medicine, University of California San Diego, La Jolla, CA, USA.
Environ Sci Pollut Res Int. 2018 Jun;25(18):17490-17498. doi: 10.1007/s11356-018-1908-3. Epub 2018 Apr 15.
The organic matter existing in nature presents as a complex system of various substances. The humic fraction refers to the humic substances (HS) and consists of humic acids (HA), fulvic acids (FA), and humins, according to solubility in aqueous solution. The physical and chemical characteristics of HA, FA, and humins depend on many factors, among which is the type of original organic material. Two processes for the stabilization of organic materials are known worldwide: composting and vermicomposting. Cattle manure, rice straw, sugarcane bagasse, and vegetable wastes from leaves were the organic residues chosen for the composting and vermicomposting processes. In this study, the differences between the HS extracted from such composted and vermicomposted residues were evaluated. The so-extracted HS were evaluated by spectroscopy in the regions of infrared and ultraviolet-visible, and pyrolysis coupled with gas chromatography with mass spectrometric detection is applied. Thus, we expect that the results obtained here indicate which of the two processes is more efficient in the biotransformation of organic residues in a short period with respect to the HS content. It was also observed that the basic units of the humic fractions generated (although they presented different degrees of maturation) are the same. Altogether, the data reported here bring to light that the structures of the HS are very similar, differing in quantities. These results can still be extrapolated to several other raw materials, since the most variable organic matrices were used here to allow this data extrapolation. In addition, the process seems to lead to the formation of more aliphatic substances, counterpoising what is found in the literature.
自然界中存在的有机物呈现出各种物质的复杂体系。腐殖质部分是指腐殖物质（HS），根据在水溶液中的溶解度，由腐殖酸（HA）、富里酸（FA）和腐黑物组成。HA、FA 和腐黑物的物理化学特性取决于许多因素，其中包括原始有机材料的类型。全球范围内已知有两种稳定有机材料的方法：堆肥和蚯蚓堆肥。牛粪、稻草、甘蔗渣和菜叶等有机废物被选为堆肥和蚯蚓堆肥过程的有机残留物。在这项研究中，评估了从这些堆肥和蚯蚓堆肥残渣中提取的 HS 之间的差异。通过红外和紫外可见光谱以及与气相色谱-质谱联用的热解对如此提取的 HS 进行了评估。因此，我们希望这里得到的结果表明，在短时间内，就 HS 含量而言，这两种过程中哪一种更有效地转化有机残渣。还观察到生成的腐殖质部分（尽管它们呈现出不同程度的成熟度）的基本单元是相同的。总的来说，这里报告的数据表明，HS 的结构非常相似，只是在数量上有所不同。这些结果还可以推广到其他几种原材料，因为这里使用了最易变的有机基质，以便进行这种数据外推。此外，该过程似乎形成了更多的脂肪物质，与文献中发现的情况相反。
