Extracellular Polymers from Nitzschia sp. for Removing Clay Minerals from Water in Mining.
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| Title: | Extracellular Polymers from Nitzschia sp. for Removing Clay Minerals from Water in Mining. |
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| Authors: | Grisales, Jeferson1 (AUTHOR), Huapaya, Katiuska1,2 (AUTHOR), Silva-Zamora, Gabriela1,3 (AUTHOR), Cisternas, Luis A.3,4 (AUTHOR), Lavin, Paris4,5 (AUTHOR), Jeison, David1,5 (AUTHOR), Zapata, Manuel1,2 (AUTHOR), Rivas, Mariella1,3 (AUTHOR) mariella.rivas@uantof.cl |
| Source: | Polymers (20734360). May2026, Vol. 18 Issue 10, p1221. 22p. |
| Subjects: | Kaolinite, Flocculants, Water purification, Glucose, Mineral industries, Diatoms, Microbial polysaccharides |
| Abstract: | Nitzschia sp., a diatom isolated from Paposo (Antofagasta, northern Chile), was evaluated as a biological solution for removing kaolinite-type clay minerals from recycled process water in large-scale copper mining. Optimization of culture conditions to maximize extracellular polymeric substance (EPS) production revealed that supplementing with 0.1 gL−1 of glucose yielded the highest EPS levels on day 17, reaching 1285 ± 58.9 mgL−1 (control equal to 237.8 ± 34 mgL−1 on day 17). However, maximum dry weight biomass productivity was achieved in the presence of sodium carbonate at a concentration of 1 gL−1 (319 ± 12.5 mgL−1d−1), significantly exceeding the productivity of the control group (242.7 ± 5.4 mgL−1d−1). Notably, low glucose supplementation enhanced EPS synthesis. Application of control-derived EPS of 1 gL−1 rapidly decreased kaolinite initial turbidity from ~2024 FNU to ~354 ± 0.74 FNU within one minute. Even more glucose-derived EPS (1 gL−1) further reduced turbidity to ~22.2 ± 0.1 FNU at 5 min, achieving a flocculation efficiency of ~98.9% after 15 min. Genomic analysis and KEGG annotation identified abundant genes for EPS and carbohydrate metabolism, including numerous glycosyltransferases, glycoside hydrolases, and multiple copies of UDP-glucose 4-epimerase, consistent with strong polysaccharide-biosynthesis capacity. Physicochemical characterization (particle sizing, HPLC, SEM, zeta-potential and FT-IR) showed EPS comprised mainly of rhamnose, fucose, arabinose, xylose and glucose, featuring functional groups (–OH, C=O/COO–, O-acetyl, uronic/guluronic signatures) that interact with kaolinite to promote aggregation. These findings demonstrate that Nitzschia-derived EPS, especially from glucose-supplemented cultures, represent promising sustainable bioflocculants for treating kaolinite-contaminated recycled water in mining operations. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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