Preparation of photocrosslinked spherical hydrogels bearing β-cyclodextrin and application in immobilizing microbes to decompose organic pollutants

• Published in: Polymer journal Vol. 54; no. 7; pp. 863 - 873
• Main Authors: Yamasaki, Hirohito, Nagasawa, Yasu-yuki, Fukunaga, Kimitoshi
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2022; Nature Publishing Group
• Subjects: 639/638/455/958; 704/172/169; Bacteria; Biomaterials; Bioorganic Chemistry; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Composition; Cyclodextrins; Decomposition; Hydrogels; Industrial wastes; Microorganisms; Modulus of elasticity; Moisture content; Moisture effects; Original Article; Phenols; Pollutants; Polyethylene glycol; Polymer Sciences; Specific gravity; Surfaces and Interfaces; Thin Films; Wastewater treatment
• ISSN: 0032-3896; 1349-0540
• DOI: 10.1038/s41428-022-00633-z

A microbe-immobilized support that improves the ability of bacteria to decompose organic pollutants by utilizing the organic inclusion effect of cyclodextrin (CyD) has been developed. Spherical hydrogels (ENTG -co- PSβCyD) were prepared by photocopolymerization of the polyethylene glycol macromonomer, ENTG, and the polysubstituted photocross-linkable β-CyD macromonomer PSβCyD. Then, the optimum composition ratio for use of this hydrogel as a microbe-immobilized support was determined, as were the phenol (PhOH)-removing abilities of PhOH-decomposing bacteria immobilized on this hydrogel. PhOH-degrading bacteria were immobilized on the spherical ENTG- co -PSβCyD hydrogel to obtain a microbe-immobilized hydrogel. The best microbe-immobilized support was obtained by using a spherical hydrogel with a PSβCyD content of approximately 28 μmol g −1 , and this resulted in a PhOH-removal rate of 0.76 mg (L h hydrogel g) −1 . This removal rate was 1.7 times faster, and the amount of free bacteria in the assay medium was 3.6 times lower than the corresponding data obtained using a microbe-immobilized hydrogel without PSβCyD. The spherical ENTG- co -PSβCyD hydrogel had a diameter of 2.9 mm, a moisture content of 63 wt%, a specific gravity of 1.16 g cm −3 and a Young’s modulus of 8.1 MPa. These results suggested that more efficient industrial wastewater treatment technologies must be developed. Spherical hydrogels (ENTG -co- PSβCyD) were prepared by photocopolymerization of the polyethylene glycol macromonomer ENTG and the polysubstituted photocross-linkable β-cyclodextrin (β-CyD) macromonomer PSβCyD. The optimum composition ratio for use of this hydrogel as a microbe-immobilized support was examined, along with the phenol (PhOH)-removing capability of PhOH-decomposing bacteria immobilized on this hydrogel. The best microbe-immobilized support had a PhOH-removal rate of 0.76 mg (L h hydrogel g) −1 . This removal rate was 1.7 times faster, and the amount of free bacteria in the assay medium was 3.6 times lower than the corresponding data obtained using a microbe-immobilized hydrogel without PSβCyD.