Past, Present, and Future Perspectives on Whey as a Promising Feedstock for Bioethanol Production by Yeast

Abstract

Concerns about fossil fuel depletion and the environmental effects of greenhouse gas emissions have led to widespread fermentation-based production of bioethanol from corn starch or sugarcane. However, competition for arable land with food production has led to the extensive investigation of lignocellulosic sources and waste products of the food industry as alternative sources of fermentable sugars. In particular, whey, a lactose-rich, inexpensive byproduct of dairy production, is available in stable, high quantities worldwide. This review summarizes strategies and specific factors essential for efficient lactose/whey fermentation to ethanol. In particular, we cover the most commonly used strains and approaches for developing high-performance strains that tolerate fermentation conditions. The relevant genes and regulatory systems controlling lactose utilization and sources of new genes are also discussed in detail. Moreover, this review covers the optimal conditions, various feedstocks that can be coupled with whey substrates, and enzyme supplements for increasing efficiency and yield. In addition to the historical advances in bioethanol production from whey, this review explores the future of yeast-based fermentation of lactose or whey products for beverage or fuel ethanol as a fertile research area for advanced, environmentally friendly uses of industrial waste products.

Cheese whey permeate as a precursor of lactose-free, galactose-rich bioproducts: an approach for optimization and application

“…Previous studies have shown that a variety of bioproducts can be obtained through the fermentation of cheese whey or WP by an assortment of fungal and bacterial species to broaden its applications. For instance, various researchers reported the production of bioethanol from these substrates using Kluyveromyces marxianus, K. lactis, Candida kefyr, and bio-engineered Escherichia coli (Koushki et al, 2012;Pasotti et al, 2017;Sampaio et al, 2020;Zou & Chang, 2022). Also, oil, volatiles, singlecell protein, and β-galactosidase have all been produced using various fungal species (Chan et al, 2018;Donzella et al, 2022;Dragone et al, 2009;Moon et al, 1978;Sampaio et al, 2020;Trigueros et al, 2016).…”

Design of a stable ethanologenic bacterial strain without heterologous plasmids and antibiotic resistance genes for efficient ethanol production from concentrated dairy waste

“…Several technologies were proposed to further valorize WP and CWP, exploiting their high lactose content to produce prebiotic oligosaccharides, carotenoids, oil, lactic acid, nanoparticles, biogas, biohydrogen and polyhydroxyalkanoate [ 3 , 6 , 9 – 13 ]. WP and CWP were also proposed as co-substrate additives for other fermentation processes [ 14 , 15 ].…”

“…One promising technology is the use of natural or engineered microbial biocatalysts, such as bacteria [ 16 – 18 ] or yeasts [ 19 ], to ferment lactose into ethanol fuel. Although advances in strain performances have been proposed and examples of industrial implementation have also been reported, the dairy waste-to-ethanol conversion technology still needs improvements to guarantee its wide adoption, based on the requirements of different bioeconomic models [ 15 , 20 , 21 ].…”

Application of Ultrafiltration To Produce Sheep’s and Goat’s Whey Based Synbiotic Kefir Products

“…Alongside with the solutions to recover and valorize CW and SCW components by membrane technologies, very promising developments have been made to convert these byproducts into value-added commodities such as biofuels, bioplastics, bacterial cellulose, food colors and flavors, bioactive peptides, and single-cell proteins, as reported by several authors [12][13][14].…”