Araújo Larissa S S, Silva Silvana Q, Teixeira Mônica C
Environmental Engineering Graduating Program - ProAmb, Federal University of Ouro Preto, Ouro Preto, 35400-000, Minas Gerais, Brazil.
Department of Biological Sciences, Institute of Exact and Biological Sciences, Federal University of Ouro Preto (UFOP), Ouro Preto, 35450-000, Minas Gerais, Brazil.
Heliyon. 2021 Feb 7;7(2):e06093. doi: 10.1016/j.heliyon.2021.e06093. eCollection 2021 Feb.
The present study aimed to investigate the ability of a microbial consortium to produce biosurfactant in the presence of two carbon sources and also to evaluate the efficiency of the cell-free supernatant cultures to mobilize As from naturally contaminated soil. and Stenotrophomonas were the main microorganisms in the microbial consortium. The pH, the incubation time, the temperature, and the glucose and glycerol ratios in the culture medium are the main factors influencing biosurfactant production. The lowest surface tension, 30 mN.m, and the higher emulsification index, 58%, were achieved at the optimum production conditions (OPC), i.e., pH 9.5, a 2.5 glucose/glycerol ratio, after three days of incubation at 25 °C. The cell-free extracts containing biosurfactants were more efficient in mobilizing As than distilled water, CaCl 0.1 mol.L; saponin, 0.1%; or sodium dodecyl sulfate, 1% during a sequential soil-flushing procedure. The As mobilization using the supernatants containing biosurfactant was sensitive to pH. The use of OPC cell-free supernatant under alkaline conditions leads to the best-obtained results: 24.6% of As removal (678 mg.kg) during sequential extractions. The toxicity reduction of the column eluted solution from the first to the seventh cycle evaluated by the germination index (GI) and morphological structures of in the ecotoxicological assessment confirmed the efficiency of the proposed treatment. seeds and seedlings were sensitive in detecting As in soil and eluted solutions with short time responses to the contaminant. Seeds development increased gradually with arsenic removal. The germination index rose from 0 to 55% after soil decontamination through the proposed soil-flushing procedure.
本研究旨在探究微生物群落联合体在两种碳源存在的情况下产生生物表面活性剂的能力，同时评估无细胞上清液培养物从天然污染土壤中 mobilize As 的效率。嗜麦芽窄食单胞菌是微生物群落联合体中的主要微生物。培养基的 pH、培养时间、温度以及葡萄糖和甘油比例是影响生物表面活性剂产生的主要因素。在最佳生产条件（OPC）下，即 pH 9.5、葡萄糖/甘油比例为 2.5、25℃培养三天后，实现了最低表面张力 30 mN.m 和较高乳化指数 58%。在连续土壤冲洗过程中，含有生物表面活性剂的无细胞提取物在 mobilize As 方面比蒸馏水、0.1 mol.L 的 CaCl、0.1%的皂苷或 1%的十二烷基硫酸钠更有效。使用含有生物表面活性剂的上清液进行 As 动员对 pH 敏感。在碱性条件下使用 OPC 无细胞上清液可获得最佳结果：在连续萃取过程中 As 去除率为 24.6%（678 mg.kg）。通过发芽指数（GI）和 ecotoxicological assessment 中种子和幼苗的形态结构评估从第一个循环到第七个循环的柱洗脱液的毒性降低，证实了所提出处理方法的有效性。种子和幼苗在检测土壤和洗脱液中的 As 时很敏感，对污染物的响应时间短。随着砷的去除，种子发育逐渐增加。通过所提出的土壤冲洗程序对土壤进行去污后，发芽指数从 0 上升到 55%。
文中“mobilize As”这里的“mobilize”可能是专业术语，在医学专业学术文献中可能有特定含义，暂直译为“动员”，可能结合上下文有更准确的表述，比如“去除砷”之类，你可根据实际专业内容调整。
