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Application of S. cerevisiae isolated from industrial effluent for zinc biosorption and zinc-enriched SCP production
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  • Forough Saraei,
  • Kurmass Amini,
  • Azam Haddadi,
  • mohaddeseh Larypoor
Forough Saraei
Karaj Islamic Azad University
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Kurmass Amini
Islamic Azad University Saveh Branch
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Azam Haddadi
Karaj Islamic Azad University
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mohaddeseh Larypoor
Islamic Azad University Tehran North Branch
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Abstract

Purpose: The aim of present study was to produce high quantity of Zn-enriched yeast biomass in the presence of zinc metal, using S. cerevisiae as an industrially important yeast strain. Methods: Yeast isolates were obtained from two alcohol factories and S. cerevisiae yeasts strains were identified using PCR method and DNA sequencing. Then, growth rate of this yeast in present of Zn2+ as well as the level of Zn2+ uptake by the yeast cells, were examined at 24-hour intervals (0, 24, 48, and 72 h), using spectrophotometry and AAS method. qRT-PCR technique was carried out to quantified expression level of Zrt1 and Fet4 in yeast cells under these conditions. Also, the effect of pH of culture medium on yeast growth rate, zinc absorbtion and Zrt1 and Fet4 expression level, was studied. After setting the optimum pH, Kjeldahl’s method was applied for assessment of total protein content of yeast cells. Results: In optimum conditions of 25 µg/ml of zinc in pH 6 and 24 h incubation, S. cerevisiae showed the maximum growth rate, zinc uptake and expression level of Zrt1 and Fet4 as Zn transporters. Also, protein content of S. cerevisiae biomass in these optimum conditions was above 50% (w/w). Discussion: we demonstrated that industrial effluents can be used to produce Zn-enriched biomass however, further researches are required.