Abstract

The present study highlights isolation, characterization and bio-adsorption strategy of a lead tolerant yeast strain designated BUSCY1 from industrial effluent of Chittaranjan Locomotive Workshop, Burdwan, West Bengal, India. The isolate was found to grow best on yeast extract peptone sucrose (YEPS) medium (2% sucrose and 0.2% yeast extract found to be optimum for growth) with profuse production of extra cellular polymeric substance and a reddish pink pigment at 30°C, pH 5.5. The strain could tolerate up to 8 mM lead nitrate. Preliminary analysis revealed that the exopolysaccharide may have some role in lead tolerance. Laboratory scale studies on removal of lead demonstrated that after 72 h of incubation amount of lead ions decreased in supernatant whereas the amount of lead ions increased in the yeast cell wash which indicated bio-adsorption by the yeast strain. The strain was identified as Rhodotorula mucilaginosa based on morphological, physiological, biochemical tests and molecular phylogenetic analysis of partial 26S rDNA molecule.

Key words: Rhodotorula mucilaginosa, lead tolerant, pigment, BLAST analysis, phylogenetic analysis, exopolysaccharide.

Abbreviation

YEPS, Yeast extract peptone sucrose; PDA, potato dextrose agar; NA,nutrient agar; YEPD, yeast extract peptone dextrose medium; YEPS, yeast extract peptone sucrose medium; YEPM, yeast extract peptone maltose; EPS, the extracellular polymer; SEM, scanning electron microscope.