Upcycling of Whey Permeate through Yeast- and Mold-Driven Fermentations under Anoxic and Oxic Conditions

• Main Authors: Justin Fisk Marcus, Timothy A. DeMarsh, Samuel David Alcaine
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: Fermentation
• Subjects: anoxic and oxic conditions; aerobic and anaerobic fermentation; fermentate; up-cycle; whey permeate; dimorphic
• Online Access: https://www.mdpi.com/2311-5637/7/1/16

Dairy manufacturing generates whey by-products, many of them considered waste; others, such as whey permeate, a powder high in lactose and minerals from deproteinated whey, have unrealized potential. This study identified yeast species capable of utilizing lactose from whey permeate to produce ethanol or organic acids, and identified fungal species that reduced the acidity of whey by-products. Reconstituted whey permeate was fermented anaerobically or aerobically for 34 days, using species from Cornell University’s Food Safety Lab, Alcaine Research Group, and Omega Labs. Yeast species: <i>Kluyveromyces marxianus, Kluyveromyces lactis, Dekkera anomala, Brettanomyces claussenii, Brettanomyces bruxellensis</i>; mold species: <i>Mucor genevensis</i> and <i>Aureobasidium pullulans</i>. Density, pH, cell concentrations, organic acids, ethanol, and sugar profiles were monitored. Under anoxic conditions, <i>K. marxianus</i> exhibited the greatest lactose utilization and ethanol production (day 20: lactose non-detectable; 4.52% ± 0.02 ethanol). Under oxic conditions, <i>D. anomala</i> produced the most acetic acid (day 34: 9.18 ± 3.38 g/L), and <i>A. pullulans</i> utilized the most lactic acid, increasing the fermentate’s pH (day 34: 0.26 ± 0.21 g/L, pH: 7.91 ± 0.51). This study demonstrates that fermentation of whey could produce value-added alcoholic or organic acid beverages, or increase the pH of acidic by-products, yielding new products and increasing sustainability.