Center of Biofuels and Bioproducts, Instituto Tecnológico Agrario de Castilla y León (ITACyL), Villarejo de Órbigo, León, Spain.
Chemical and Environmental Bioprocess Engineering Group, Natural Resources Institute (IRENA), University of León, León, Spain.
PLoS One. 2018 Dec 31;13(12):e0210002. doi: 10.1371/journal.pone.0210002. eCollection 2018.
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.
筛选了 8 株酵母属（Saccharomyces）和克鲁维酵母属（Kluyveromyces）的菌株，用于在不添加营养物质的情况下发酵高乳糖负荷奶酪乳清渗透物（CWP）（>130 g/L 乳糖）。使用响应面法（RSM）对两种预选菌株，马克斯克鲁维酵母 DSM 5422 和酿酒酵母 Ethanol Red 的发酵条件（温度、pH 值和时间）进行优化，以最大限度地提高发酵性能（乙醇浓度、乙醇得率和乳糖消耗）。在优化条件下，马克斯克鲁维酵母 DSM 5422 在短短 44 小时内达到 6%（v/v）的乙醇浓度。此外，还评估了将该菌株固定在四种不同无机载体（塑料、玻璃和 Tygon 硅橡胶拉西格环和氧化铝珠）上的可行性。玻璃拉西格环和氧化铝珠随着时间的推移表现出更稳定的性能，在 1000 小时内产生 60 g/L 的乙醇浓度，这显著降低了酵母培养成本。结果表明，使用 CWP 可以成功地在简单经济的工艺中生产乙醇，这为乳制品工业的废物处理提供了有吸引力的替代方案。
