As one of the most promising groups of microbes, lactic acid bacteria (LAB) can synthesize metabolites that can be used in different industries over the world, mainly in the pharmaceutical, food, and dairy industries. In this study, a novel exopolysaccharide was extracted and isolated from the probiotic strain Lactobacillus reuteri B2, and assessed on biological activity and its possible application as a biosorbent for the removal of Ni²⁺ ions from contaminated water. New exopolysaccharide was characterized using FTIR, SEM, XRD, NMR, MALDI-TOF MS, and TGA/DTG analysis. Biological assays included antioxidative activity, cytotoxic assay, and adhesion assay of L. reuteri B2 to HT29 cells. Our hypothesis was that if this exopolysaccharide is nontoxic, it can be used as a novel biomaterial for the possible application of the removal of Ni²⁺ ions from contaminated water. The scavenging effect of nontoxic exopolysaccharide was 76% at 2 mg/mL using ABTS assay, in biological assays, while the removal efficiency of nickel from the aqueous solution was 92.96% in biosorption study. According to these results, this exopolysaccharide can be considered a very promising biomaterial for potential application in different industries, from pharmacy to wastewater treatments.

Graphical abstract

中文翻译：

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由益生菌菌株罗伊氏乳杆菌 B2 产生的新型胞外多糖：提取、生物学特性和从污染水中去除 Ni2+ 离子的可能应用

作为最有前途的微生物群之一，乳酸菌（LAB）可以合成代谢物，可用于全球不同行业，主要用于制药、食品和乳制品行业。在这项研究中，从益生菌罗伊氏乳杆菌B2中提取和分离了一种新型胞外多糖，并评估了其生物活性及其作为生物吸附剂去除污染水中Ni ^{2+离子的可能性。}使用 FTIR、SEM、XRD、NMR、MALDI-TOF MS 和 TGA/DTG 分析对新的胞外多糖进行了表征。生物测定包括罗伊氏乳杆菌的抗氧化活性、细胞毒性测定和粘附测定B2 至 HT29 细胞。我们的假设是，如果这种胞外多糖是无毒的，它可以用作一种新型生物材料，可能用于从污染水中去除 Ni ^2+离子。在生物测定中，无毒胞外多糖在 2 mg/mL 时的清除效果为 76%，使用 ABTS 测定，而在生物吸附研究中从水溶液中去除镍的效率为 92.96%。根据这些结果，这种胞外多糖可以被认为是一种非常有前景的生物材料，可用于从制药到废水处理的不同行业。

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