Effect of passive cell immobilization of co-cultured yeasts on the whey fermentation and alcohols production

• Published in: Journal of cleaner production 2022-11, Vol.375, p.133988, Article 133988
• Main Authors: Valdez Castillo, Mariana, Brar, Satinder Kaur, Arriaga, Sonia, Blais, Jean-François, Avalos Ramirez, Antonio
• Format: Article
• Language: English
• Subjects: 2-Phenylethanol production; Perlite; Plastic rings; Whey fermentation; Wood biochar; Yeast immobilization
• ISSN: 0959-6526; 1879-1786
• DOI: 10.1016/j.jclepro.2022.133988

Whey is one of the main residues of the dairy industry and its valorization by fermentation is an emergent practice that contributes to the circular economy and sustainable development. Whey fermentation with specialized yeast strains produces value-added biomolecules, such as fusel alcohols of high interest for the pharmaceutic, food and cosmetic industries due to their aromatic and flavor properties. The present study aimed to develop the whey fermentation with the yeasts Kluyveromyces marxianus and Debaryomyces hansenii immobilized on inert support, to increase cell density and 2-phenylethanol (2-PE) production. Biochar synthesized from wood feedstock, perlite and filter Kaldnes plastic rings were used as supports for the cell immobilization. They were selected based on their different nature and physical properties such as porous structure and rough surface, to study the effect of different supports on yeast biofilm development. Also, functional groups such as hydroxyl, carbonyl, siloxane, and aliphatic hydrocarbons were useful for the development of covalent bonds and electrostatic forces between cells-support. The yeast immobilization increased the 2-PE production, especially on the plastic rings and perlite, obtaining 0.56 ± 0.01 g/L of 2-PE for the suspended culture and up to 0.91 ± 0.01 g/L for the immobilized co-culture on filter Kaldnes plastic rings. •Porosity and roughness of biochar and perlite benefit the yeast attachment.•Diversity of functional groups on supports facilitate the yeast cells' attachment.•The potential of high-density polyethylene to yeast biofilm formation was studied.•A dense and uniform biofilm decreases cell stress and the alcohols production.•Fine biofilms trigger the cells' secondary metabolism for 2-phenylethanol production.