Characteristics of copper tolerance in Yarrowia lipolytica

Abstract

We discovered that a mutant strain of the dimorphic yeast Yarrowia lipolytica could grow in the yeast form in high concentrations of copper sulfate. The amount of metal accumulated by Y. lipolytica increased with increasing copper concentrations in the medium. Washing with 100 mM EDTA released at least 60% of the total metal from the cells, but about 20-25 micromol/g DW persisted, which represented about 30% of the soluble fraction of cultured cells. The soluble fraction (mainly cytosol) contained only about 10% of the total metal content within cells cultured in medium supplemented with 6 mM copper. We suggest that although a high copper concentration induces an efflux mechanism, the released copper becomes entrapped in the periplasm and in other parts of the cell wall. Washing with EDTA liberated not only copper ions, but also melanin, a brown pigment that can bind metal and which located at the cell wall. These findings indicated that melanin participates in the mechanism of metal accumulation. Culture in medium supplemented with copper obviously enhanced the activities of Cu, Zn-SOD, but not of Mn-SOD.

The potential capability of bacteria and yeast strains isolated from Rungkut Industrial Sewage in Indonesia as a bioaccumulators and biosorbents of copper

“…This might be due to the survival mechanism of yeast strains by increasing the production of pigments in the cell wall in response to the pressure of adding heavy metals. A similar result was also reported by Ito et al (2007) who mentioned that Yarrowia lipoprosita grown at high concentrations of copper sulfate produced chocolate pigments which could bind metals in cell walls. Copper accumulation of bacterial and yeast strains It is well recognized that microorganisms have a high affinity for metals and can accumulate heavy metals by a variety of mechanisms (Rehman et al 2008).…”

Proteomic study of the yeast Rhodotorula mucilaginosa RCL-11 under copper stress

“…Studies with R. mucilaginosa RCL-11 have demonstrated an increase in SOD activity when cells were exposed to increasing exposure times and copper concentrations (Villegas et al 2009). In addition, the yeast Yarrowia lipolytica was able to grow at high concentrations of copper sulfate and showed higher CuZnSOD activity under these conditions (Ito et al 2007). An augmented CuZnSOD protein concentration was also demonstrated in a S. cerevisiae Dyfh1 mutant, whose metal ion homeostasis was deregulated .…”

Biotechnological applications of Yarrowia lipolytica: Past, present and future

“…Moreover, it was shown that metallothionein, a protective protein with a potential role in binding heavy metals, could be produced by Y. lipolytica. Ito et al (2007) showed that Y. lipolytica also can be grown on high concentrations (2-4 mM) of copper sulfate. Bankar et al (2009b) (Shinde et al, 2012).…”