Metabolic engineering of<i>Saccharomyces cerevisiae</i>for lactose/whey fermentation

Domingues, Lucı́lia; Guimarães, Pedro M. R.; Oliveira, Carla Cristina Marques de

doi:10.4161/bbug.1.3.10619

Cited by 68 publications

(34 citation statements)

References 83 publications

(83 reference statements)

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“…Genetic manipulations that allow S. cerevisiae to metabolise lactose (such as cloning the genes that encode b-galactosidase and lactose permease) have been attempted, but the results are often inferior to the results from yeasts that are able to ferment lactose naturally (Domingues et al 2010). The identification of yeasts that present new traits or properties can be useful for ethanol production from low cost feedstocks, such as cheese whey.…”

Section: Introductionmentioning

confidence: 99%

The high fermentative metabolism of Kluyveromyces marxianus UFV-3 relies on the increased expression of key lactose metabolic enzymes

Diniz

Silveira

Fietto

et al. 2011

Antonie van Leeuwenhoek

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The aim of this work was to obtain insights about the factors that determine the lactose fermentative metabolism of Kluyveromyces marxianus UFV-3. K. marxianus UFV-3 and Kluyveromyces lactis JA6 were cultured in a minimal medium containing different lactose concentrations (ranging from 0.25 to 64 mmol l(-1)) under aerobic and hypoxic conditions to evaluate their growth kinetics, gene expression and enzymatic activity. The increase in lactose concentration and the decrease in oxygen level favoured ethanol yield for both yeasts but in K. marxianus UFV-3 the effect was more pronounced. Under hypoxic conditions, the activities of β-galactosidase and pyruvate decarboxylase from K. marxianus UFV-3 were significantly higher than those in K. lactis JA6. The expression of the LAC4 (β-galactosidase), RAG6 (pyruvate decarboxylase), GAL7 (galactose-1-phosphate uridylyltransferase) and GAL10 (epimerase) genes in K. marxianus UFV-3 was higher under hypoxic conditions than under aerobic conditions. The high expression of genes of the Leloir pathway, LAC4 and RAG6, associated with the high activity of β-galactosidase and pyruvate decarboxylase contribute to the high fermentative flux in K. marxianus UFV-3. These data on the fermentative metabolism of K. marxianus UFV-3 will be useful for optimising the conversion of cheese whey lactose to ethanol.

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Section: Introductionmentioning

confidence: 99%

The high fermentative metabolism of Kluyveromyces marxianus UFV-3 relies on the increased expression of key lactose metabolic enzymes

Diniz

Silveira

Fietto

et al. 2011

Antonie van Leeuwenhoek

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“…The lactose utilization is modelled by assuming that substrate is consumed only for biomass conversion, and by combining with Monod equation, the substrate utilization can be predicted by Equation 3. While ethanol as a product of fermentation was strongly linked to biomass production.…”

Section: Kinetic Model Predictionmentioning

confidence: 99%

“…Lactose can be converted into ethanol through fermentation process using yeast, especially species of Kluyveromyces [3]. The presence of lactose in whey as the sole carbohydrate can limit the growth of other microorganisms.…”

mentioning

confidence: 99%

Ethanol Production from Whey by Kluyveromyces marxianus in Batch Fermentation System: Kinetics Parameters Estimation

Ariyanti

Hadiyanto

2012

Bull. Chem. React. Eng. Catal.

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Whey is the liquid remaining after milk has been curdled and strained. It is a by-product of the manufacture of cheese or casein and has several commercial uses. In environmental point of view, whey is kind of waste which has high pollution level due to it's contain high organic compound with BOD and COD value 50 and 80 g/L respectively. On the other side, whey also contain an amount of lactose (4.5%-5%); lactose can be used as carbon source and raw material for producing ethanol via fermentation using yeast strain Kluyveromyces marxianus. The objective of this research is to investigate the kinetics of ethanol production from crude whey through fermentation using Kluyveromyces marxianus and to estimate the kinetics parameter using available model. The yeast was able to metabolize most of the lactose within 16 h to give 8.64 g/L ethanol, 4.43 g/L biomass, and remain the 3.122 g/L residual lactose. From the results presented it also can be concluded that common kinetic model for microbial growth, substrate consumption, and product formation is a good alternative to describe an experimental batch fermentation of Kluyveromyces marxianus grown on a medium composed of whey. The model was found to be capable of reflecting all batch culture phases to a certain degree of accuracy, giving the parameter value: µmax, Ks, YX/S, α, β : 0.32, 10.52, 0.095, 1.52, and 0.11 respectively.

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“…Moreover, several process engineering and/or genetic engineering strategies have been devised in order to accomplish lactose fermentation using Saccharomyces cerevisiae, whose wild strains lack a lactose metabolization system (for reviews see [6,15]). We have transferred the LAC12 (encoding the lactose permease) and LAC4 (encoding the intracellular ß-galactosidase) genes of Kluyveromyces lactis into a strongly flocculent S. cerevisiae host strain, obtaining a slow lactose-fermenting recombinant strain [8].…”

Section: Introductionmentioning

confidence: 99%

Fermentation of deproteinized cheese whey powder solutions to ethanol by engineered Saccharomyces cerevisiae: effect of supplementation with corn steep liquor and repeated-batch operation with biomass recycling by flocculation

Silva¹,

Guimarães²,

Teixeira³

et al. 2010

J Ind Microbiol Biotechnol

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The lactose in cheese whey is an interesting substrate for the production of bulk commodities such as bio-ethanol, due to the large amounts of whey surplus generated globally. In this work, we studied the performance of a recombinant Saccharomyces cerevisiae strain expressing the lactose permease and intracellular beta-galactosidase from Kluyveromyces lactis in fermentations of deproteinized concentrated cheese whey powder solutions. Supplementation with 10 g/l of corn steep liquor significantly enhanced whey fermentation, resulting in the production of 7.4% (v/v) ethanol from 150 g/l initial lactose in shake-flask fermentations, with a corresponding productivity of 1.2 g/l/h. The flocculation capacity of the yeast strain enabled stable operation of a repeated-batch process in a 5.5-l air-lift bioreactor, with simple biomass recycling by sedimentation of the yeast flocs. During five consecutive batches, the average ethanol productivity was 0.65 g/l/h and ethanol accumulated up to 8% (v/v) with lactose-to-ethanol conversion yields over 80% of theoretical. Yeast viability (>97%) and plasmid retention (>84%) remained high throughout the operation, demonstrating the stability and robustness of the strain. In addition, the easy and inexpensive recycle of the yeast biomass for repeated utilization makes this process economically attractive for industrial implementation.

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Metabolic engineering ofSaccharomyces cerevisiaefor lactose/whey fermentation

Cited by 68 publications

References 83 publications

The high fermentative metabolism of Kluyveromyces marxianus UFV-3 relies on the increased expression of key lactose metabolic enzymes

The high fermentative metabolism of Kluyveromyces marxianus UFV-3 relies on the increased expression of key lactose metabolic enzymes

Ethanol Production from Whey by Kluyveromyces marxianus in Batch Fermentation System: Kinetics Parameters Estimation

Fermentation of deproteinized cheese whey powder solutions to ethanol by engineered Saccharomyces cerevisiae: effect of supplementation with corn steep liquor and repeated-batch operation with biomass recycling by flocculation

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