Antarctic yeasts: potential use in a biologic treatment of textile azo dyes

RUSCASSO, F.; CAVELLO, I.; CURUTCHET, G.; CAVALITTO, S.

Bioresources and Bioprocessing

Springer

Año: 2022 vol. 9

We investigated the dye-removal potential of a collection of 61 cold-adapted yeasts from the King George Island,Antarctica, on agar plates supplemented with 100 mg L?1 of several textile dyes; among which isolates 81% decolorized Reactive Black 5 (RB-5), with 56% decolorizing Reactive Orange 16, but only 26% doing so with Reactive Blue 19and Acid Blue 74. Furthermore, we evaluated the ligninolytic potential using 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic-acid) diammonium salt-, 3,5-dimethoxy-4-hydroxybenzaldehydazine-, or manganese-supplemented platesbut detected no activity, possibly due to a dye-removal mechanism involving reductases. The removal kinetics werestudied in liquid medium supplemented with 100 mg L?1 of RB-5 in a selection of 9 yeasts. The highest volumetricremoval rates (η) were found for Candida sake 41E (4.14 mg L?1 h?1), Leucosporidium muscorum F20A (3.90 mg L?1 h?1),and Cystoflobasidium infrmominiatum F13E (3.90 mg L?1 h?1). Diferent UV?Vis spectra were obtained if the dyeremoval occurred by biodegradation or biosorption/bioaccumulation. L. muscorum F20A was selected to study thedye-removal mechanism of RB-5 and the efect of diferent chemical and environmental parameters on the process.Optimum dye-removal conditions were obtained with 10 g L?1 of glucose within an initial medium pH range of 5.0 to6.0. Up to 700 mg L?1 of dye could be removed in 45 h. High-performance liquid chromatography profles obtainedwere consistent with a biodegradation of the dye. Phytotoxicity was estimated by calculating the 50%-inhibition concentration (IC50) with Lactuca sativa L. seeds. These fndings propose psychrophilic yeasts as a novel environmentallysuitable alternative for the treatment of dye-industry wastewaters.