Fermentation of lactose to bio-ethanol by yeasts as part of integrated solutions for the valorisation of cheese whey

• Main Author: Guimarães, Pedro M. R.
• Publication Date: 2010
• Other Authors: Teixeira, J. A., Domingues, Lucília
• Format: Article
• Language: eng
• Source: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Download full: https://hdl.handle.net/1822/10543
• topic: Lactose fermentation; Cheese whey; Bio-ethanol; Yeast; Kluyveromyces; Recombinant S. cerevisiae; Science & Technology

Cheese whey, the main dairy by-product, is increasingly recognized as a source of many bioactive valuable compounds. Nevertheless, the most abundant component in whey is lactose (ca. 5% w/v), which represents a significant environmental problem. Due to the large lactose surplus generated, its conversion to bio-ethanol has long been considered as a possible solution for whey bioremediation. In this review, fermentation of lactose to ethanol is discussed, focusing on wild lactose-fermenting yeasts, particularly Kluyveromyces marxianus, and recombinant Saccharomyces cerevisiae strains. The early efforts in the screening and characterization of the fermentation properties of wild lactose-consuming yeasts are reviewed. Furthermore, emphasis is given on the latter advances in engineering S. cerevisiae strains for efficient whey-to-ethanol bioprocesses. Examples of industrial implementation are briefly discussed, illustrating the viability of whey-to-ethanol systems. Current developments on strain engineering together with the growing market for biofuels will likely boost the industrial interest in such processes.