Assessing the textile-dye decolorization potential of psychrophilic and psychrotolerant yeasts from 25 de Mayo/King George island (Antarctica)

PACHECO MARIANA SOLEDAD; DOMÍNGUEZ FACUNDO GABRIEL; TORRES MARIELA ANALÍA; MARTORELL MARÍA MARTHA; RUBERTO LUCAS ADOLFO MARIO; MAC CORMACK, WALTER; MARTINEZ LM; PAJOT, HIPÓLITO F.; CARLOS G. NIETO PEÑALVER

Jornada; XL Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2022

Sociedad de Biología de Cuyo

Antarctic environments typically present low temperatures, high solar radiation and low nutrient availability, being one of the harshest environments on Earth. Psychrophilic and psychrotolerant yeasts from Antarctic soils and cryoconites have adapted to such conditions, being an interesting source of new enzymes with great biotechnological potential. This work intends to prove the textile dye decolorizing potential of 139 yeasts isolated from soil and cryoconite samples from 25 de Mayo/King George Island, Antarctica. Isolates were cultivated in YM, and NDM (Normal Decolorization Medium) media at 15, 20 and 25°C, and classified into psychrophilic and psychrotolerant according to their growth profiles. Textile dye decolorization was evaluated in the same two media, plus 200 mg/L of one of four commercially available reactive azo dyes: Vilmafix Blue RR-BB (CI, Reactive Blue 221), Vilmafix Red 7B-HE (CI, Reactive Red 141), Vilmafix® Black B-V (CI, Reactive Black 5), or Vilmafix® Green RR-4B (CI, Reactive Green). Plates were incubated for 72 h at 15, 20 or 25°C, depending on the yeast isolate. Dye decolorization haloes and colony dyeing were recorded daily and used to select the most promising isolates. Of 139 isolates, 34% were classified as psychrophilic (growing only at 15°C) while the remaining 66% were classified as psychrotolerant (growing at all the assayed temperatures), irrespective of the medium assayed. Forty-five isolates produce haloes in at least one of the tested dyes in NDM, while only 40 yeast produced haloes in YM. 15 isolates were selected for further studies Isolates A075 and Y28D produced intense haloes without colony dyeing; isolates Y67, Y70 and Y75 produced intense haloes and get dyed only at the edge of the colonies while the remaining ten isolates, A092, A099, A104, A105, A106, A107, Y6, Y59, Y73 and Y84, produced neat haloes with a significant colorization of the entire colonies. The obtained results prove the biotechnological potential of Antarctic yeasts, raising the possibility of designing more efficient dye-decolorizing methods at low temperatures.