Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454, Marne-la-Vallée, France; University of Napoli "Federico II", Department of Civil, Architectural and Environmental Engineering, 80125, Napoli, Italy.
Université Paris-Est, Laboratoire Géomatériaux et Environnement (LGE), EA 4508, UPEM, 77454, Marne-la-Vallée, France.
J Environ Manage. 2021 Feb 15;280:111648. doi: 10.1016/j.jenvman.2020.111648. Epub 2020 Nov 16.
Sewage sludge digestate is a valuable organic waste which can be used as fertilizer in soil bioremediation. Sewage sludge digestate is not only a good source of nutrients but is also rich in bacteria carrying alkB genes, which are involved in aliphatic hydrocarbons metabolism. Increase of alkB genes ratio in polluted soils has been observed to improve bioremediation efficiency. In this study, for the first time, the genetic potential of indigenous microorganisms of digestate to degrade petroleum products was assessed. The objectives were to study petroleum hydrocarbons (PHCs) removal together with shifts in soil taxa and changes in the concentration of alkB genes after digestate application. Initial alkB genes concentration in contaminated soils and digestate was 1.5% and 4.5%, respectively. During soil incubation with digestate, alkB genes percentage increased up to 11.5% and after the addition of bacteria immobilized onto biochar this value increased up to 60%. Application of digestate positively affected soil respiration and bacterial density, which was concomitant with enhanced PHCs degradation. Incubation of soil amended with digestate resulted in 74% PHCs decrease in 2 months, while extra addition of bacteria immobilized onto biochar increased this value up to 95%. The use of digestate affected the microbial community profiles by increasing initial bacterial density and diversity, including taxa containing recognized PHCs degraders. This study reveals the great potential of digestate as a soil amendment which additionally improves the abundance of alkB genes in petroleum contaminated soils.
污水污泥消化物是一种有价值的有机废物，可用作土壤生物修复中的肥料。污水污泥消化物不仅是营养物质的良好来源，而且还富含携带 alkB 基因的细菌，这些基因参与脂肪族烃类的代谢。在污染土壤中增加 alkB 基因的比例已被观察到可提高生物修复效率。在这项研究中，首次评估了消化物中土著微生物降解石油产品的遗传潜力。目的是研究石油烃 (PHC) 的去除以及土壤分类群的变化和消化物施用后 alkB 基因浓度的变化。污染土壤和消化物中初始 alkB 基因浓度分别为 1.5%和 4.5%。在消化物处理土壤的过程中，alkB 基因的百分比增加到 11.5%，而在添加固定在生物炭上的细菌后，这一数值增加到 60%。消化物的施用对土壤呼吸和细菌密度产生了积极影响，这与 PHCs 的降解增强相一致。在 2 个月内，添加了消化物的土壤中 PHCs 减少了 74%，而额外添加固定在生物炭上的细菌则将这一数值增加到 95%。消化物的使用通过增加初始细菌密度和多样性来影响微生物群落谱，包括含有公认的 PHCs 降解菌的分类群。这项研究揭示了消化物作为土壤改良剂的巨大潜力，它可以增加石油污染土壤中 alkB 基因的丰度。
