Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy

Carvalho, Patrícia; Costa, Carlos E.; Baptista, Sara Isabel Leite; Domingues, Lucı́lia

doi:10.18331/brj2021.8.4.4

Cited by 15 publications

(3 citation statements)

References 132 publications

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“…Cultures are also less prone to contaminations, as they ferment at an acidic pH. S. cerevisiae is considered the favorite species for ethanol production because of its high ethanol yield in media with glucose and ethanol tolerance, and is expected to play a central role in multi-waste valorization approaches [47]. However, its main drawback is its incapacity to ferment the xylose that is released during hydrolysis pretreatment of lignocellulosic biomass [2].…”

Section: Discussionmentioning

confidence: 99%

Saccharomyces cerevisiae Cells Lacking the Zinc Vacuolar Transporter Zrt3 Display Improved Ethanol Productivity in Lignocellulosic Hydrolysates

Terra-Matos

Teixeira

Santos-Pereira

et al. 2022

JoF

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Yeast-based bioethanol production from lignocellulosic hydrolysates (LH) is an attractive and sustainable alternative for biofuel production. However, the presence of acetic acid (AA) in LH is still a major problem. Indeed, above certain concentrations, AA inhibits yeast fermentation and triggers a regulated cell death (RCD) process mediated by the mitochondria and vacuole. Understanding the mechanisms involved in AA-induced RCD (AA-RCD) may thus help select robust fermentative yeast strains, providing novel insights to improve lignocellulosic ethanol (LE) production. Herein, we hypothesized that zinc vacuolar transporters are involved in vacuole-mediated AA-RCD, since zinc enhances ethanol production and zinc-dependent catalase and superoxide dismutase protect from AA-RCD. In this work, zinc limitation sensitized wild-type cells to AA-RCD, while zinc supplementation resulted in a small protective effect. Cells lacking the vacuolar zinc transporter Zrt3 were highly resistant to AA-RCD, exhibiting reduced vacuolar dysfunction. Moreover, zrt3Δ cells displayed higher ethanol productivity than their wild-type counterparts, both when cultivated in rich medium with AA (0.29 g L−1 h−1 versus 0.11 g L−1 h−1) and in an LH (0.73 g L−1 h−1 versus 0.55 g L−1 h−1). Overall, the deletion of ZRT3 emerges as a promising strategy to increase strain robustness in LE industrial production.

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Section: Discussionmentioning

confidence: 99%

Saccharomyces cerevisiae Cells Lacking the Zinc Vacuolar Transporter Zrt3 Display Improved Ethanol Productivity in Lignocellulosic Hydrolysates

Terra-Matos

Teixeira

Santos-Pereira

et al. 2022

JoF

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“…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 ].…”

Section: Introductionmentioning

confidence: 99%

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

Pasotti

Marchi

Casanova

et al. 2023

Biotechnol Biofuels

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Engineering sustainable bioprocesses that convert abundant waste into fuels is pivotal for efficient production of renewable energy. We previously engineered an Escherichia coli strain for optimized bioethanol production from lactose-rich wastewater like concentrated whey permeate (CWP), a dairy effluent obtained from whey valorization processes. Although attractive fermentation performances were reached, significant improvements are required to eliminate recombinant plasmids, antibiotic resistances and inducible promoters, and increase ethanol tolerance. Here, we report a new strain with chromosomally integrated ethanologenic pathway under the control of a constitutive promoter, without recombinant plasmids and resistance genes. The strain showed extreme stability in 1-month subculturing, with CWP fermentation performances similar to the ethanologenic plasmid-bearing strain. We then investigated conditions enabling efficient ethanol production and sugar consumption by changing inoculum size and CWP concentration, revealing toxicity- and nutritional-related bottlenecks. The joint increase of ethanol tolerance, via adaptive evolution, and supplementation of small ammonium sulphate amounts (0.05% w/v) enabled a fermentation boost with 6.6% v/v ethanol titer, 1.2 g/L/h rate, 82.5% yield, and cell viability increased by three orders of magnitude. Our strain has attractive features for industrial settings and represents a relevant improvement in the existing ethanol production biotechnologies.

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“…and a source of value-added products such as organic acids, bacterial cellulose, polymers, bioethanol, etc. [5,6] In addition, bioethanol produced mostly from plant biomass, such as starchy and cellulosic substrates [7,8] shows considerable promise because to its renewable nature. This alternative fuel has the potential to partially substitute fossil fuels and reduce the greenhouse effect by emitting low levels of carbon.…”

Section: Introductionmentioning

confidence: 99%

Bacterial Nanocellulose‐Based Composite Biocatalysts for Starch‐to‐Bioethanol Valorization under Simultaneous Saccharification and Fermentation

Drosos,

Dima,

Kandylis

et al. 2023

Starch Stärke

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Composite biocatalysts (CB) consisting of amylases and Saccharomyces cerevisiae immobilized separately on bacterial nanocellulose (BNC) are used for the process of simultaneous saccharification and fermentation (SSF) of starch (5%, w/v) for bioethanol production. Parameters such as: i) addition of phosphates and/or divalent metal‐ions salts during the co‐immobilization process of the amylases, ii) required co‐immobilization time, iii) fermentation temperature and initial pH of starch, and iv) CB as single or double freeze‐dried are studied. The utilization of double freeze‐dried CB exhibits fermentation efficiency 89.9% and ethanol yield 0.51 g ethanol g−1 starch while the single freeze‐dried CB 81.1% and 0.46 g ethanol g−1 starch, respectively. In the case of double freeze‐dried CB, the fermentation efficiency decreases by only 27.1% in two‐recycling batches, while in the single freeze‐dried one decreases by 51.3%. The application of double freeze‐dried CB can be used for: i) the eco‐friendly biosynthesis of value‐added bioproducts; ii) the promising option for fuel‐grade bioethanol through starchy wastes or foodstuff starchy residues treatment, and iii) the implementation of industrialization. Finally, to simulate an industrial process of one‐step SSF of starch by applying a CB model, a technoeconomic analysis is evaluated, where using BNCs makes the bioprocess cost‐effective and environmentally favorable, simultaneously.

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Yeast cell factories for sustainable whey-to-ethanol valorisation towards a circular economy

Cited by 15 publications

References 132 publications

Saccharomyces cerevisiae Cells Lacking the Zinc Vacuolar Transporter Zrt3 Display Improved Ethanol Productivity in Lignocellulosic Hydrolysates

Saccharomyces cerevisiae Cells Lacking the Zinc Vacuolar Transporter Zrt3 Display Improved Ethanol Productivity in Lignocellulosic Hydrolysates

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

Bacterial Nanocellulose‐Based Composite Biocatalysts for Starch‐to‐Bioethanol Valorization under Simultaneous Saccharification and Fermentation

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