Diez-Marulanda Juan C, Brandão Pedro F B
Universidad Nacional de Colombia, Sede Bogotá, Facultad de Ciencias, Departamento de Química, Grupo de Estudios para la Remediación y Mitigación de Impactos Negativos al Ambiente (GERMINA), Av. Carrera 30 # 45-03, 111321 Bogotá, Colombia.
3 Biotech. 2023 Mar;13(3):98. doi: 10.1007/s13205-023-03495-1. Epub 2023 Feb 27.
Cadmium (Cd) is a toxic heavy metal that causes serious health problems and is present in agriculturally important soils in Colombia, such as the ones used for cocoa farming. Recently, the use of ureolytic bacteria by the Microbiologically Induced Carbonate Precipitation (MICP) activity has been proposed as an alternative to mitigate the availability of Cd in contaminated soils. In this study, 12 urease-positive bacteria able to grow in the presence of Cd(II) were isolated and identified. Three were selected based on urease activity, precipitates formation and growth, with two belonging to the genus (codes 4.1a and 5b) and one to (code 6a). These isolates exhibited low urease activity levels (3.09, 1.34 and 0.31 μmol mL h, respectively), but could raise the pH to values close to 9.0 and to produce carbonate precipitates. It was shown that the presence of Cd affects the growth of the selected isolates. However, urease activity was not negatively influenced. In addition, the three isolates were observed to efficiently remove Cd from solution. The two isolates presented maximum removals of 99.70% and 99.62%, with initial 0.05 mM Cd(II) in the culture medium (supplemented with urea and Ca(II)) at 30 °C and 144 h of incubation. For the isolate, the maximum removal was 91.23% at the same conditions. Thus, this study evidences the potential use of these bacteria for bioremediation treatments in samples contaminated with Cd, and it is one of the few reports that shows the high cadmium removal capacity of bacteria from the genus .
The online version contains supplementary material available at 10.1007/s13205-023-03495-1.
镉（Cd）是一种有毒重金属，会引发严重的健康问题，并且存在于哥伦比亚具有农业重要性的土壤中，例如用于可可种植的土壤。最近，有人提出利用微生物诱导碳酸盐沉淀（MICP）活性的尿素分解细菌作为减轻污染土壤中镉有效性的一种替代方法。在本研究中，分离并鉴定了12株能够在Cd（II）存在下生长的尿素酶阳性细菌。根据尿素酶活性、沉淀物形成和生长情况选择了3株，其中2株属于 属（编号4.1a和5b），1株属于 属（编号6a）。这些分离株表现出较低的尿素酶活性水平（分别为3.09、1.34和0.31 μmol mL h），但能将pH值提高到接近9.0并产生碳酸盐沉淀。结果表明，Cd的存在会影响所选分离株的生长。然而，尿素酶活性并未受到负面影响。此外，观察到这3株分离株能有效地从溶液中去除Cd。在30°C培养144小时的条件下，在培养基（添加尿素和Ca（II））中初始Cd（II）浓度为0.05 mM时，两株 属分离株的最大去除率分别为99.70%和99.62%。对于 属分离株，在相同条件下最大去除率为91.23%。因此，本研究证明了这些细菌在镉污染样品生物修复处理中的潜在用途，并且这是少数显示 属细菌具有高镉去除能力的报告之一。
在线版本包含可在10.1007/s13205-023-03495-1获取的补充材料。
