*Yeast from Distillery Plants: A New Approach DOI: http://dx.doi.org/10.5772/intechopen.86291*

*Advances in Grape and Wine Biotechnology*

**7. Bioaccumulation of heavy metals**

Australia). Tests were semiquantitative.

around 20%, reaching 30% in some cases.

adsorption was not detected or was very low.

combined with other processes could be a feasible strategy.

ing produced the highest elimination, followed by *Z. fermentati*.

*kudriavzevii* released Cr (VI) into the media after 6 h of contact.

microbial reserves of undoubted biotechnological interest.

vitality were found to have potential use as starters in distillery plants.

and at time 0, 0.2, 3, 6, 24 and 48 hours were taken.

For bioremediation proposals, a selective elimination of metals using yeasts

Different metallic ions were tested [Cr (VI), Pb (II), Cd (II)]. Metal solutions added to inactivate biomass (obtained by thermal treatment, 5 min/121°C) were incubated at 20°C with horizontal shaking (150 rpm). Aliquots before inoculation

Metallic ion determination was performed by means of an inductively coupled plasma optical emission spectrometer (ICP-OES: Varian Vista-Pro, Mulgrave, VIC,

Very different results were obtained depending on the yeast species as well as the metal tested for the bioaccumulation experiment (**Table 4**). The greatest metal elimination took place for Pb (II) with *H. meyeri, Z. bailii*, *P. membranaefaciens, P. kudriavzevii* and *S'codes ludwigii*, which presented an elimination range of

This percentage diminished by nearly half for Cd (II), with *P. kudriavzevii* hav-

Cr (VI) was eliminated in a much lower proportion, highlighting only *P. membranaefaciens* with 10% elimination, followed by the majority of the yeasts in which

In general, the metal removal was instantaneous, and during the first 10 min of contact, no additional adsorption was observed. However, in some cases, *S'codes ludwigii* for Pb (II) and *H. uvarum* for Cd (II), the adsorption was progressive, possibly due to the different compositions of polysaccharides and proteins in the cell wall [31]. Unfortunately, *S. cerevisiae*, a by-product of the wine industry and suitable for this type of process, offered a low percentage of elimination for Pb (II) and a medium percentage for the other two metals compared with the rest of the yeasts of the same group. Appreciable desorption processes were not observed, although *P.* 

This initial study of yeast populations isolated from very old distilleries reflects the great existing biodiversity of this valuable yeast niche. This contrasts with what occurs in wine cellars, where the intra and interspecific variability of yeasts have been reduced drastically due to the starter use. *Saccharomyces*, *Pichia* and *Candida* are the genera found in large proportions. Some species were only isolated for certain substrates, like *T. delbrueckii* in sweet piquettes and *P. galeiformis* in fermented piquettes. The yeast biota of these environments is varied, so these ecological niches are

In fact, a great number of thermophilic *Saccharomyces* strains with a great cell

On the other hand, yeasts coming from very old distilleries might be used as biocontrol and bioremediation agents. *Pichia* sp. inhibited all molds effectively and might be produced in an aerated fermentation process and used as an antifungal postharvest treatment of fruits. In the case of *S'codes ludwigii*, *P. membranaefaciens* and *P. kudriavzevii*, the elimination of Pb (II) was achieved, with the adsorption

*P. kudriavzevii* is a good candidate for both biocontrol and bioremediation because it efficiently inhibited molds and had the highest accumulation average of

**178**

**8. Conclusions**

being almost instantaneous.

the tested metals.

**Table 4.**
