黑水虻生物转化残留物二次堆肥物料生化及溶解性有机质动态演化特征

Dynamic features of biochemical properties and dissolved organic matter in black soldier fly larvae vermicompost during secondary composting

餐厨垃圾黑水虻转化技术因其周期短、转化效率高、昆虫制品价值潜力大等优点而受到重视,但对黑水虻生物转化后的残留物的再处理鲜见报道.结合生化测试和波谱分析,在为期49 d的残留物条垛式二次堆肥过程中,研究物料的生化特征及其溶解性有机质(dissolved organic matter,DOM)的动态变化特征.结果显示:堆体物料温度在7 d内快速升至63.8℃,之后缓慢降低至结束时的27.7℃,物料含水量从初始的65.4%逐步下降至38.6%,处理后物料DOM、速效磷、总氮和铵态氮含量分别降低了69.1%、41.7%、11.8%和22.6%,而硝态氮含量提高了18.7倍.三维荧光光谱、傅里叶变换红外光谱以及核磁共振分析发现:(1)物料DOM组分中酚类、醇类、脂肪、蛋白质以及乳酸类等物质逐步降解;(2)碳水化合物烷基链烃类物质含量逐渐下降,且链烃支链逐渐变短,烯烃类、芳香组类以及多糖类等物质被降解的同时又生成新的同类物质;(3)β-木糖、β-半乳糖、β-阿拉伯糖、α-半乳糖、α-阿拉伯糖以及α-葡萄糖等溶解性单糖相对增加,有机胺、含甲基有机质以及有强抗病毒功能的肌苷三磷酸类等物质相对增加.随着二次堆肥的进行,物料DOM化学组分多样性增加,结构复杂性下降,稳定性和芳香性组分相对增加.本研究表明黑水虻生物转化残留物经二次堆肥后,腐殖化程度加深,产品质量得到提升.该结果可为残留物资源化再利用以及餐厨垃圾黑水虻生物转化技术提供理论依据.

The utility of black soldier fly larvae(BSFL) in bioconversion technology applications, such as kitchen waste treatment and reuse, has attracted public attention due to its short cycle, high conversion efficiency,and the potentially high value of bioconversion bioproducts. However, few studies have reported on the reprocessing of residues after BSFL bioconversion(i.e., vermicompost). In this study, we used biochemical tests and spectral analyses to assess the biochemical features of BSFL vermicompost and the dynamic change characteristics of dissolved organic matter(DOM) during 49 days of secondary composting under the stack fermentation process. Vermicompost temperature was shown to rapidly increase to 63.8 ℃ within 7 days, thereafter, slowly decreasing to 27.7 ℃ by the end of the 49-day period. In contrast, the vermicompost moisture content decreased gradually from 65.4% to 38.6%. After the treatment, the DOM content, available phosphorus, total nitrogen, and ammonium nitrogen in the vermicompost decreased by 69.1%, 41.7%, 11.8%,and 22.6%, respectively, while nitrate nitrogen content saw an 18.7-fold increase. Furthermore, we used three-dimensional fluorescence spectroscopy, Fourier transform infrared spectroscopy, and nuclear magnetic resonance analysis to show that firstly, phenols, alcohols, fats, proteins, lactic acids, and other substances in the DOM of the vermicompost gradually degraded;secondly, the general alkane content and the content of alkanes in carbohydrates decreased gradually, and the alkane branched chain shortened, in contrast, the alkenes, aromatics, and polysaccharides were shown to degrade over time, with new similar substances forming;and thirdly, a relative increase in soluble monosaccharides, such as β-xylose, β-galactose, β-arabinose, α-galactose,α-arabinose, and α-glucose, as well as organic amines, methyl organic matter, and inosine triphosphate with strong antiviral functions was demonstrated. Secondary composting resulted in an increase in the diversity of DOM chemical components, a decrease in the complexity of the DOM structure, and finally, an increase in the stability and aromatic components in vermicompost. In summary, secondary composting resulted in a deepening of the humification degree of DOM in vermicompost and improved the bioproduct quality.