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Bio-utilization of cheese manufacturing wastes (cheese whey powder) for bioethanol and specific product (galactonic acid) production via a two-step bioprocess
- Zhou, Xin, Hua, Xia, Huang, Lu, Xu, Yong
- Bioresource technology 2019 v.272 pp. 70-76
- Gluconobacter oxydans, Saccharomyces cerevisiae, beta-galactosidase, bioethanol, bioprocessing, cheese whey, cheesemaking, coagulation, environmental impact, ethanol, galactose, glucose, lactose, manufacturing, milk, pollutants, value added, wastes, whey powder, whey protein
- Cheese whey, produced from coagulation of milk during cheese manufacture, is a major environmental pollutant. The most abundant component in cheese whey is lactose, which is a potential resource for various value-added chemicals. Here, a two-step bioprocess using Saccharomyces cerevisiae and Gluconobacter oxydans to bioconvert cheese whey into ethanol and galactonic acid was first proposed. First, the lactose in cheese whey powder was pretreated with β-galactosidase to obtain glucose and galactose. Subsequently, the glucose was selectively fermented to ethanol by S. cerevisiae to enable G. oxydans-mediated biooxidation of galactose to galactonic acid. Finally, approximately 110 g ethanol, 320 g galactonate, and 150 g mixed protein (residual cheese whey protein and cell protein) was produced from 1 kg CWP. These results are suggestive of alternative methods for management of cheese whey, which may reduce its impact on the environment and result in production of value-added biochemicals.