Cheese whey is the major by-product of the dairy industry, and its disposal constitutes an environmental concern. The production of cheese whey has been increasing, with 190 million tonnes per year being produced nowadays. Therefore, it is emergent to consider different routes for cheese whey utilization. The great nutritional value of cheese whey turns it into an attractive substrate for biotechnological applications. Currently, cheese whey processing includes a protein fractionating step that originates the permeate, a lactose-reach stream further used for valorisation. In the last decades, yeast fermentation has brought several advances to the search for biorefinery alternatives. From the plethora of value-added products that can be obtained from cheese whey, ethanol is the most extensively explored since it is the alternative biofuel most used worldwide. Thus, this review focuses on the different strategies for ethanol production from cheese whey using yeasts as promising biological systems, including its integration in lignocellulosic biorefineries. These valorisation routes encompass the improvement of the fermentation process as well as metabolic engineering techniques for the introduction of heterologous pathways, resorting mainly to Kluyveromyces sp. and Saccharomyces cerevisiae strains. The solutions and challenges of the several strategies will be unveiled and explored in this review.
Graphical Abstract
Highlights
Whey is the major by-product of the dairy industry, being an environmental concern.
Bioethanol is the prevalent product obtained from cheese whey fermentation.
Kluyveromyces sp. and Saccharomyces cerevisiae are the most used hosts for whey valorisation.
Novel valorisation routes are rising due to the advances in metabolic engineering.
Integration of multi-valorisation pathways will positively impact process economics.
Tomaszewska, M., Białończyk, L., 2016. Ethanol production from whey in a bioreactor coupled with direct contact membrane distillation, in: Catal. Today. Elsevier. 268 pp. 156-163.
Carvalho, P., Costa, C., Baptista, S., & Domingues, L. (2021). Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy. Biofuel Research Journal, 8(4), 1529-1549. doi: 10.18331/BRJ2021.8.4.4
MLA
Patrícia Carvalho; Carlos E. Costa; Sara L. Baptista; Lucília Domingues. "Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy". Biofuel Research Journal, 8, 4, 2021, 1529-1549. doi: 10.18331/BRJ2021.8.4.4
HARVARD
Carvalho, P., Costa, C., Baptista, S., Domingues, L. (2021). 'Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy', Biofuel Research Journal, 8(4), pp. 1529-1549. doi: 10.18331/BRJ2021.8.4.4
VANCOUVER
Carvalho, P., Costa, C., Baptista, S., Domingues, L. Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy. Biofuel Research Journal, 2021; 8(4): 1529-1549. doi: 10.18331/BRJ2021.8.4.4