Yeast screening and cell immobilization on inert supports for ethanol production from cheese whey permeate with high lactose loads

PLoS One. 2018 Dec 31;13(12):e0210002. doi: 10.1371/journal.pone.0210002. eCollection 2018.

Abstract

Eight yeast strains of the genera Saccharomyces and Kluyveromyces were screened to ferment high lactose-load cheese whey permeate (CWP) (>130 g/L lactose) without nutrient supplementation. The fermentation conditions (temperature, pH and time) were optimized to maximize the fermentation performance (ethanol titer, ethanol yield and lactose consumption) for the two preselected strains, K. marxianus DSM 5422 and S. cerevisiae Ethanol Red, using a response surface methodology (RSM). Under optimized conditions, K. marxianus DSM 5422 attained ethanol titers of 6% (v/v) in only 44 h. Moreover, the feasibility of immobilizing this strain on four different inorganic supports (plastic, glass and Tygon silicone Raschig rings and alumina beads) was assessed. Glass Raschig rings and alumina beads showed a more stable performance over time, yielding ethanol titers of 60 g/L during 1,000 hours, which remarkably reduces yeast cultivation costs. Results demonstrate the feasibility of using CWP for successful ethanol production in a simple and economical process, which represents an attractive alternative for waste treatment in dairy industries.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cells, Immobilized / metabolism*
  • Cheese*
  • Ethanol / metabolism*
  • Kluyveromyces / genetics
  • Kluyveromyces / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Whey / chemistry*

Substances

  • Ethanol

Grants and funding

The authors are grateful to FEDER European Regional Development funds (FEDER) for financial support. María Hijosa-Valsero is supported by a postdoctoral contract (DOC-INIA, grant number DOC 2013-010) funded by the Spanish National Institute for Agricultural and Food Research and Technology (INIA) and the European Social Fund.