Nowadays, exopolysaccharides (EPS) produced from bacterial cells are manufactured for their use in different industries in the world, mainly in the food, pharmaceutical, and wastewater industries. The characteristics of EPS, such as being biodegradable, safe, high adsorption capacity, and reusable, make them significant and potential applications in the purification of contaminated water of heavy metals. In this study, the possible application in biosorption Ni2+ ions from contaminated water was assessed using this exopolysaccharide as a biosorbent. The new exopolysaccharide from the bacterial strain K. oxytoca J7 was extracted, isolated, and characterized using SEM, FTIR, XRD, TGA/DTG, and MALDI-TOF MS analysis. Likewise, the cytotoxic activity was performed for EPS from K. oxytoca J7 strain. The aim of this study was to investigate the possible application of non-toxic exopolysaccharide in the purification of contaminated water by removing Ni2+ ions. The results obtained from the biosorption study showed that the Langmuir model is well suited to describe the adsorption process of Ni2+ ions by EPS from K. oxytoca J7, with a maximum adsorption capacity of 269.97 mg g–1. The importance of this study is the possible use of natural nontoxic exopolysaccharide extracted from the pathogen microorganism, K. oxytoca J7, for the removal of Ni2+ ions from the contaminated water.

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