Cadmium (Cd) is a highly toxic metal that frequently contaminates our environment. In this study, the bioflocculant-producing, cadmium-resistant Escherichia fergusonii ZSF-15 was characterized from Paharang drain, Bawa Chak, Faisalabad, Pakistan. The Cd-resistant E. fergusonii was used to determine the bioflocculant production using yeast-peptone-glycerol medium (pH 6.5) supplemented with 50 mg L⁻¹ of Cd. The culture was incubated for 3 days at 37 °C in a rotary shaker at 120 rpm. The fermentation broth was centrifuged at 4000 g for 10 min after the incubation period. The maximum flocculating activity by isolate ZSF-15 was found to be 71.4% after 48 h of incubation. According to the Fourier transform infrared spectroscopy analysis, the bioflocculant produced by strain ZSF-15 was comprised of typical polysaccharide and protein, i.e. hydroxyl, carboxyl, and amino groups. The strain ZSF-15 exhibited bioflocculant activity at range of pH (6–8) and temperature (35–50℃). Maximum flocculation activity (i.e. 71%) was observed at 47℃, whereas 63% flocculation production was observed at pH 8. In the present study, antioxidant enzyme profile of ZSF-15 was also evaluated under cadmium stress. A significant increase in antioxidant enzymes including superoxide dismutase (118%) and ascorbate peroxidase (28%) was observed, whereas contents of catalase (86%), glutathione transferase (13%), and peroxidase (8%) were decreased as compared to control.

镉 (Cd) 是一种剧毒金属，经常污染我们的环境。在这项研究中，对来自巴基斯坦费萨拉巴德 Bawa Chak 的 Paharang 排水沟的产生生物絮凝剂的抗镉埃希氏菌ZSF-15 进行了鉴定。抗镉弗格森氏菌用于测定使用补充有50 mg L ^-1镉的酵母-蛋白胨-甘油培养基（pH 6.5）的生物絮凝剂产量。将培养物在 37°C 下在旋转摇床中以 120 rpm 孵育 3 天。孵育期后将发酵液在4000g下离心10分钟。培养 48 小时后，发现分离株 ZSF-15 的最大絮凝活性为 71.4%。根据傅里叶变换红外光谱分析，菌株ZSF-15产生的生物絮凝剂由典型的多糖和蛋白质组成，即羟基、羧基和氨基。菌株ZSF-15在pH值（6-8）和温度（35-50℃）范围内表现出生物絮凝活性。在 47℃ 时观察到最大絮凝活性（即 71%），而在 pH 8 时观察到 63% 的絮凝产量。在本研究中，还在镉胁迫下评估了 ZSF-15 的抗氧化酶谱。与对照组相比，抗氧化酶显着增加，包括超氧化物歧化酶（118%）和抗坏血酸过氧化物酶（28%），而过氧化氢酶（86%）、谷胱甘肽转移酶（13%）和过氧化物酶（8%）的含量下降控制。