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Estrada M, Navarrete C, Møller S, Procentese A, Martínez JL. Utilization of salt-rich by-products from the dairy industry as feedstock for recombinant protein production by Debaryomyces hansenii. Microb Biotechnol 2022; 16:404-417. [PMID: 36420701 PMCID: PMC9871522 DOI: 10.1111/1751-7915.14179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/26/2022] [Accepted: 10/30/2022] [Indexed: 11/27/2022] Open
Abstract
The dairy industry processes vast amounts of milk and generates high amounts of secondary by-products, which are still rich in nutrients (high Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) levels) but contain high concentrations of salt. The current European legislation only allows disposing of these effluents directly into the waterways with previous treatment, which is laborious and expensive. Therefore, as much as possible, these by-products are reutilized as animal feed material and, if not applicable, used as fertilizers adding phosphorus, potassium, nitrogen, and other nutrients to the soil. Finding biological alternatives to revalue dairy by-products is of crucial interest in order to improve the utilization of dry dairy matter and reduce the environmental impact of every litre of milk produced. Debaryomyces hansenii is a halotolerant non-conventional yeast with high potential for this purpose. It presents some beneficial traits - capacity to metabolize a variety of sugars, tolerance to high osmotic environments, resistance to extreme temperatures and pHs - that make this yeast a well-suited option to grow using complex feedstock, such as industrial waste, instead of the traditional commercial media. In this work, we study for the first time D. hansenii's ability to grow and produce a recombinant protein (YFP) from dairy saline whey by-products. Cultivations at different scales (1.5, 100 and 500 ml) were performed without neither sterilizing the medium nor using pure water. Our results conclude that D. hansenii is able to perform well and produce YFP in the aforementioned salty substrate. Interestingly, it is able to outcompete other microorganisms present in the waste without altering its cell performance or protein production capacity.
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Affiliation(s)
- Mònica Estrada
- Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
| | - Clara Navarrete
- Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
| | - Sønke Møller
- SBU Food, Arla Food Ingredients Group P/SViby JDenmark
| | - Alessandra Procentese
- Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark,Department of Industrial EngineeringUniversity of SalernoSalernoItaly
| | - José L. Martínez
- Department of Biotechnology and BiomedicineTechnical University of DenmarkKgs. LyngbyDenmark
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Past, Present, and Future Perspectives on Whey as a Promising Feedstock for Bioethanol Production by Yeast. J Fungi (Basel) 2022; 8:jof8040395. [PMID: 35448626 PMCID: PMC9031875 DOI: 10.3390/jof8040395] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 04/02/2022] [Accepted: 04/11/2022] [Indexed: 12/10/2022] Open
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.
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Uncoupling glucose sensing from GAL metabolism for heterologous lactose fermentation in Saccharomyces cerevisiae. Biotechnol Lett 2021; 43:1607-1616. [PMID: 33937967 DOI: 10.1007/s10529-021-03136-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 04/20/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES Development of a system for direct lactose to ethanol fermentation provides a market for the massive amounts of underutilized whey permeate made by the dairy industry. For this system, glucose and galactose metabolism were uncoupled in Saccharomyces cerevisiae by deleting two negative regulatory genes, GAL80 and MIG1, and introducing the essential lactose hydrolase LAC4 and lactose transporter LAC12, from the native but inefficient lactose fermenting yeast Kluyveromyces marxianus. RESULTS Previously, integration of the LAC4 and LAC12 genes into the MIG1 and NTH1 loci was achieved to construct strain AY-51024M. Low rates of lactose conversion led us to generate the Δmig1Δgal80 diploid mutant strain AY-GM from AY-5, which exhibited loss of diauxic growth and glucose repression, subsequently taking up galactose for consumption at a significantly higher rate and yielding higher ethanol concentrations than strain AY-51024M. Similarly, in cheese whey permeate powder solution (CWPS) during three, repeated, batch processes in a 5L bioreactor containing either 100 g/L or 150 g/L lactose, the lactose uptake and ethanol productivity rates were both significantly greater than that of AY-51024M, while the overall fermentation times were considerably lower. CONCLUSIONS Using the Cre-loxp system for deletion of the MIG1 and GAL80 genes to relieve glucose repression, and LAC4 and LAC12 overexpression to increase lactose uptake and conversion provides an efficient basis for yeast fermentation of whey permeate by-product into ethanol.
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Panagopoulos V, Dima A, Boura K, Bosnea L, Nigam PS, Kanellaki M, Koutinas AA. Cell factory models of non-engineered S. cerevisiae containing lactase in a second layer for lactose fermentation in one batch. Enzyme Microb Technol 2021; 145:109750. [PMID: 33750540 DOI: 10.1016/j.enzmictec.2021.109750] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 01/20/2021] [Accepted: 01/24/2021] [Indexed: 11/29/2022]
Abstract
The objective of this project was to ferment lactose and whey to ethanol in one-step process. Models of cell factory of non-engineered S.cerevisiae have been proposed to ferment lactose. The cell factory of non-engineered S. cerevisiae/SG-lactase was prepared by the addition, of a starch gel solution containing lactase on non-engineered S. cerevisiae, and freeze drying of it. The 2-layer non engineered S.cerevisiae-TC/SG-lactase factory was prepared by immobilizing S. cerevisiae on the internal layer of tubular cellulose (TC), and the lactase enzyme was contained in the upper layer of starch gel (SG) covering cells of S. cerevisiae. Using such cell factory for the fermentation of lactose, alcohol yield of 23-32 mL/L at lactose conversion of 71-100%. The improvement in alcohol yield by cell factory versus co-immobilization of lactase enzyme and S. cerevisiae on alginates, was found in the range of 28-78%. Likewise, the cell factories are more effective than engineered S. cerevisiae. The fermentation of whey instead of lactose resulted in a significant reduction of the fermentation time. Freeze-dried cell factories led to improved results as compared with non-freeze dried. When lactase was substituted with L. casei, ethanol and lactic acid were produced simultaneously at high concentrations, but in a much longer fermentation time. The cell factories can be considered as models for white biotechnology using lactose containing raw materials. This suggested cell factory model can be applied for other bioconversions using the appropriate enzymes and cells, in the frame of White Biotechnology without genetic modification.
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Affiliation(s)
- Vassilios Panagopoulos
- Food Biotechnology Group, Department of Chemistry, University of Patras, 26504, Patras, Greece
| | - Agapi Dima
- Food Biotechnology Group, Department of Chemistry, University of Patras, 26504, Patras, Greece
| | - Konstantina Boura
- Food Biotechnology Group, Department of Chemistry, University of Patras, 26504, Patras, Greece
| | - Loulouda Bosnea
- Food Biotechnology Group, Department of Chemistry, University of Patras, 26504, Patras, Greece
| | - Poonam S Nigam
- Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, UK
| | - Maria Kanellaki
- Food Biotechnology Group, Department of Chemistry, University of Patras, 26504, Patras, Greece
| | - Athanasios A Koutinas
- Food Biotechnology Group, Department of Chemistry, University of Patras, 26504, Patras, Greece.
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Shen J, Chen J, Jensen PR, Solem C. Development of a novel, robust and cost-efficient process for valorizing dairy waste exemplified by ethanol production. Microb Cell Fact 2019; 18:51. [PMID: 30857537 PMCID: PMC6410493 DOI: 10.1186/s12934-019-1091-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/20/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Delactosed whey permeate (DWP) is a side stream of whey processing, which often is discarded as waste, despite of its high residual content of lactose, typically 10-20%. Microbial fermentation is one of the most promising approaches for valorizing nutrient rich industrial waste streams, including those generated by the dairies. Here we present a novel microbial platform specifically designed to generate useful compounds from dairy waste. As a starting point we use Corynebacterium glutamicum, an important workhorse used for production of amino acids and other important compounds, which we have rewired and complemented with genes needed for lactose utilization. To demonstrate the potential of this novel platform we produce ethanol from lactose in DWP. RESULTS First, we introduced the lacSZ operon from Streptococcus thermophilus, encoding a lactose transporter and a β-galactosidase, and achieved slow growth on lactose. The strain could metabolize the glucose moiety of lactose, and galactose accumulated in the medium. After complementing with the Leloir pathway (galMKTE) from Lactococcus lactis, co-metabolization of galactose and glucose was accomplished. To further improve the growth and increase the sugar utilization rate, the strain underwent adaptive evolution in lactose minimal medium for 100 generations. The outcome was strain JS95 that grew fast in lactose mineral medium. Nevertheless, JS95 still grew poorly in DWP. The growth and final biomass accumulation were greatly stimulated after supplementation with NH4+, Mn2+, Fe2+ and trace minerals. In only 24 h of cultivation, a high cell density (OD600 of 56.8 ± 1.3) was attained. To demonstrate the usefulness of the platform, we introduced a plasmid expressing pyruvate decarboxylase and alcohol dehydrogenase, and managed to channel the metabolic flux towards ethanol. Under oxygen-deprived conditions, non-growing suspended cells could convert 100 g/L lactose into 46.1 ± 1.4 g/L ethanol in DWP, a yield of 88% of the theoretical. The resting cells could be re-used at least three times, and the ethanol productivities obtained were 0.96 g/L/h, 2.2 g/L/h, and 1.6 g/L/h, respectively. CONCLUSIONS An efficient process for producing ethanol from DWP, based on C. glutamicum, was demonstrated. The results obtained clearly show a great potential for this newly developed platform for producing value-added chemicals from dairy waste.
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Affiliation(s)
- Jing Shen
- National Food Institute, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Jun Chen
- National Food Institute, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Peter Ruhdal Jensen
- National Food Institute, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
| | - Christian Solem
- National Food Institute, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
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Naumova ES, Sadykova AZ, Michailova YV, Naumov GI. Polymorphism of lactose genes in the dairy yeasts Kluyveromyces marxianus, potential probiotic microorganisms. Microbiology (Reading) 2017. [DOI: 10.1134/s0026261717030122] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Medium optimization and kinetics modeling for the fermentation of hydrolyzed cheese whey permeate as a substrate for Saccharomyces cerevisiae var. boulardii. Biochem Eng J 2016. [DOI: 10.1016/j.bej.2016.02.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Becerra M, Cerdán ME, González-Siso MI. Biobutanol from cheese whey. Microb Cell Fact 2015; 14:27. [PMID: 25889728 PMCID: PMC4404668 DOI: 10.1186/s12934-015-0200-1] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Accepted: 01/26/2015] [Indexed: 11/17/2022] Open
Abstract
At present, due to environmental and economic concerns, it is urgent to evolve efficient, clean and secure systems for the production of advanced biofuels from sustainable cheap sources. Biobutanol has proved better characteristics than the more widely used bioethanol, however the main disadvantage of biobutanol is that it is produced in low yield and titer by ABE (acetone-butanol-ethanol) fermentation, this process being not competitive from the economic point of view. In this review we summarize the natural metabolic pathways for biobutanol production by Clostridia and yeasts, together with the metabolic engineering efforts performed up to date with the aim of either enhancing the yield of the natural producer Clostridia or transferring the butanol production ability to other hosts with better attributes for industrial use and facilities for genetic manipulation. Molasses and starch-based feedstocks are main sources for biobutanol production at industrial scale hitherto. We also review herewith (and for the first time up to our knowledge) the research performed for the use of whey, the subproduct of cheese making, as another sustainable source for biobutanol production. This represents a promising alternative that still needs further research. The use of an abundant waste material like cheese whey, that would otherwise be considered an environmental pollutant, for biobutanol production, makes economy of the process more profitable.
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Affiliation(s)
- Manuel Becerra
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía Celular e Molecular, Facultade de Ciencias, Universidade da Coruña, Campus de A Coruña, 15071, A Coruña, Spain.
| | - María Esperanza Cerdán
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía Celular e Molecular, Facultade de Ciencias, Universidade da Coruña, Campus de A Coruña, 15071, A Coruña, Spain.
| | - María Isabel González-Siso
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Departamento de Bioloxía Celular e Molecular, Facultade de Ciencias, Universidade da Coruña, Campus de A Coruña, 15071, A Coruña, Spain.
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Maicas S, Moukadiri I, Nieto A, Valentín E. Construction of an expression vector for production and purification of human somatostatin in Escherichia coli. Mol Biotechnol 2014; 55:150-8. [PMID: 23640683 DOI: 10.1007/s12033-013-9667-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Somatostatin/growth hormone-inhibiting hormone is the peptide that inhibits secretion of somatotropin/growth hormone. Solid-phase synthesis methods are being currently used to produce somatostatin. Recombinant peptide synthesis is widely described for the production of small proteins and peptides; however, the production at industrial scale of peptides for biopharmaceutical applications is limited for economic reasons. Here, we propose the use of a new pGB-SMT plasmid to produce Somatostatin, as a C-terminal fusion protein with a Kluyveromyces lactis β-galactosidase fragment. To facilitate removal of that fragment by CNBr cleavage, a methionine residue was introduced at the N-terminal of the hormone peptide. The use of this construction enables an IPTG-free expression system. The suitability of this procedure has been assessed in a 15 l scale-up experiment yielding almost 300 mg, with purity >99 % and it is being implemented for commercial scale. The plasmid pGB-SMT here described is an alternative option for a cheap and high expression of other short peptide hormones.
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Affiliation(s)
- Sergi Maicas
- Departament de Microbiologia i Ecologia, Universitat de València, Dr. Moliner, 50, 46100, Burjassot, Spain,
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Fermentation of lactose to bio-ethanol by yeasts as part of integrated solutions for the valorisation of cheese whey. Biotechnol Adv 2010; 28:375-84. [DOI: 10.1016/j.biotechadv.2010.02.002] [Citation(s) in RCA: 278] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Revised: 02/03/2010] [Accepted: 02/04/2010] [Indexed: 11/18/2022]
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Domingues L, Guimarães PMR, Oliveira C. Metabolic engineering of Saccharomyces cerevisiae for lactose/whey fermentation. Bioeng Bugs 2009; 1:164-71. [PMID: 21326922 DOI: 10.4161/bbug.1.3.10619] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2009] [Revised: 11/13/2009] [Accepted: 11/13/2009] [Indexed: 11/19/2022] Open
Abstract
Lactose is an interesting carbon source for the production of several bio-products by fermentation, primarily because it is the major component of cheese whey, the main by-product of dairy activities. However, the microorganism more widely used in industrial fermentation processes, the yeast Saccharomyces cerevisiae, does not have a lactose metabolization system. Therefore, several metabolic engineering approaches have been used to construct lactose-consuming S. cerevisiae strains, particularly involving the expression of the lactose genes of the phylogenetically related yeast Kluyveromyces lactis, but also the lactose genes from Escherichia coli and Aspergillus niger, as reviewed here. Due to the existing large amounts of whey, the production of bio-ethanol from lactose by engineered S. cerevisiae has been considered as a possible route for whey surplus. Emphasis is given in the present review on strain improvement for lactose-to-ethanol bioprocesses, namely flocculent yeast strains for continuous high-cell-density systems with enhanced ethanol productivity.
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Affiliation(s)
- Lucília Domingues
- IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, Braga, Portugal.
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Hildebrandt P, Wanarska M, Kur J. A new cold-adapted beta-D-galactosidase from the Antarctic Arthrobacter sp. 32c - gene cloning, overexpression, purification and properties. BMC Microbiol 2009; 9:151. [PMID: 19631003 PMCID: PMC2723119 DOI: 10.1186/1471-2180-9-151] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2009] [Accepted: 07/27/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The development of a new cold-active beta-D-galactosidases and microorganisms that efficiently ferment lactose is of high biotechnological interest, particularly for lactose removal in milk and dairy products at low temperatures and for cheese whey bioremediation processes with simultaneous bio-ethanol production. RESULTS In this article, we present a new beta-D-galactosidase as a candidate to be applied in the above mentioned biotechnological processes. The gene encoding this beta-D-galactosidase has been isolated from the genomic DNA library of Antarctic bacterium Arthrobacter sp. 32c, sequenced, cloned, expressed in Escherichia coli and Pichia pastoris, purified and characterized. 27 mg of beta-D-galactosidase was purified from 1 L of culture with the use of an intracellular E. coli expression system. The protein was also produced extracellularly by P. pastoris in high amounts giving approximately 137 mg and 97 mg of purified enzyme from 1 L of P. pastoris culture for the AOX1 and a constitutive system, respectively. The enzyme was purified to electrophoretic homogeneity by using either one step- or a fast two step- procedure including protein precipitation and affinity chromatography. The enzyme was found to be active as a homotrimeric protein consisting of 695 amino acid residues in each monomer. Although, the maximum activity of the enzyme was determined at pH 6.5 and 50 degrees C, 60% of the maximum activity of the enzyme was determined at 25 degrees C and 15% of the maximum activity was detected at 0 degrees C. CONCLUSION The properties of Arthrobacter sp. 32cbeta-D-galactosidase suggest that this enzyme could be useful for low-cost, industrial conversion of lactose into galactose and glucose in milk products and could be an interesting alternative for the production of ethanol from lactose-based feedstock.
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Affiliation(s)
- Piotr Hildebrandt
- Department of Microbiology, Chemical Faculty, Gdańsk University of Technology, Narutowicza 11/12, 80-952 Gdańsk, Poland.
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Cebollero E, Gonzalez-Ramos D, Gonzalez R. Construction of a recombinant autolytic wine yeast strain overexpressing thecsc1-1allele. Biotechnol Prog 2009; 25:1598-604. [DOI: 10.1002/btpr.269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Overexpression of the glucoamylase-encoding STA1 gene of Saccharomyces cerevisiae var. diastaticus in laboratory and industrial strains of Saccharomyces. World J Microbiol Biotechnol 2008. [DOI: 10.1007/s11274-008-9837-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Fermentation of high concentrations of lactose to ethanol by engineered flocculent Saccharomyces cerevisiae. Biotechnol Lett 2008; 30:1953-8. [DOI: 10.1007/s10529-008-9779-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2008] [Revised: 05/27/2008] [Accepted: 06/04/2008] [Indexed: 10/21/2022]
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Adaptive evolution of a lactose-consuming Saccharomyces cerevisiae recombinant. Appl Environ Microbiol 2008; 74:1748-56. [PMID: 18245248 DOI: 10.1128/aem.00186-08] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The construction of Saccharomyces cerevisiae strains that ferment lactose has biotechnological interest, particularly for cheese whey fermentation. A flocculent lactose-consuming S. cerevisiae recombinant expressing the LAC12 (lactose permease) and LAC4 (beta-galactosidase) genes of Kluyveromyces lactis was constructed previously but showed poor efficiency in lactose fermentation. This strain was therefore subjected to an evolutionary engineering process (serial transfer and dilution in lactose medium), which yielded an evolved recombinant strain that consumed lactose twofold faster, producing 30% more ethanol than the original recombinant. We identified two molecular events that targeted the LAC construct in the evolved strain: a 1,593-bp deletion in the intergenic region (promoter) between LAC4 and LAC12 and a decrease of the plasmid copy number by about 10-fold compared to that in the original recombinant. The results suggest that the intact promoter was unable to mediate the induction of the transcription of LAC4 and LAC12 by lactose in the original recombinant and that the deletion established the transcriptional induction of both genes in the evolved strain. We propose that the tuning of the expression of the heterologous LAC genes in the evolved recombinant was accomplished by the interplay between the decreased copy number of both genes and the different levels of transcriptional induction for LAC4 and LAC12 resulting from the changed promoter structure. Nevertheless, our results do not exclude other possible mutations that may have contributed to the improved lactose fermentation phenotype. This study illustrates the usefulness of simple evolutionary engineering approaches in strain improvement. The evolved strain efficiently fermented threefold-concentrated cheese whey, providing an attractive alternative for the fermentation of lactose-based media.
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Rech R, Ayub MAZ. Fed-batch bioreactor process with recombinant Saccharomyces cerevisiae growing on cheese whey. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2006. [DOI: 10.1590/s0104-66322006000400001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- R. Rech
- Federal University of Rio Grande do Sul State, Brazil
| | - M. A. Z. Ayub
- Federal University of Rio Grande do Sul State, Brazil
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Naumov GI, Naumova ES, Barrio E, Querol A. Genetic and molecular study of the inability of the yeast Kluyveromyces lactis var. drosophilarum to ferment lactose. Microbiology (Reading) 2006. [DOI: 10.1134/s0026261706030027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Rubio-Texeira M. Endless versatility in the biotechnological applications of Kluyveromyces LAC genes. Biotechnol Adv 2006; 24:212-25. [PMID: 16289464 DOI: 10.1016/j.biotechadv.2005.10.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 10/04/2005] [Indexed: 11/20/2022]
Abstract
Most microorganisms adapted to life in milk owe their ability to thrive in this habitat to the evolution of mechanisms for the use of the most abundant sugar present on it, lactose, as a carbon source. Because of their lactose-assimilating ability, Kluyveromyces yeasts have long been used in industrial processes involved in the elimination of this sugar. The identification of the genes conferring Kluyveromyces with a system for permeabilization and intracellular hydrolysis of lactose (LAC genes), along with the current possibilities for their transfer into alternative organisms through genetic engineering, has significantly broadened the industrial profitability of lactic yeasts. This review provides an updated overview of the general properties of Kluyveromyces LAC genes, and the multiple techniques involving their biotechnological utilization. Emphasis is also made on the potential that some of the latest technologies, such as the generation of transgenics, will have for a further benefit in the use of these and related genes.
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Affiliation(s)
- Marta Rubio-Texeira
- 68-541, Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, 02139, USA.
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Rubio-Texeira M. A comparative analysis of the GAL genetic switch between not-so-distant cousins: Saccharomyces cerevisiae versus Kluyveromyces lactis. FEMS Yeast Res 2005; 5:1115-28. [PMID: 16014343 DOI: 10.1016/j.femsyr.2005.05.003] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 05/12/2005] [Accepted: 05/18/2005] [Indexed: 11/21/2022] Open
Abstract
Despite their close phylogenetic relationship, Kluyveromyces lactis and Saccharomyces cerevisiae have adapted their carbon utilization systems to different environments. Although they share identities in the arrangement, sequence and functionality of their GAL gene set, both yeasts have evolved important differences in the GAL genetic switch in accordance to their relative preference for the utilization of galactose as a carbon source. This review provides a comparative overview of the GAL-specific regulatory network in S. cerevisiae and K. lactis, discusses the latest models proposed to explain the transduction of the galactose signal, and describes some of the particularities that both microorganisms display in their regulatory response to different carbon sources. Emphasis is placed on the potential for improved strategies in biotechnological applications using yeasts.
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Affiliation(s)
- Marta Rubio-Texeira
- Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA.
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Adam AC, Rubio-Texeira M, Polaina J. Lactose: The Milk Sugar from a Biotechnological Perspective. Crit Rev Food Sci Nutr 2005; 44:553-7. [PMID: 15969327 DOI: 10.1080/10408690490931411] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Lactose is a very important sugar because of its abundance in the milk of humans and domestic animals. Lactose is a valuable asset as a basic nutrient and the main substrate in fermentative processes that led to the production of fermented milk products, such as yogurt and kefir. In some instances, lactose also can be a problem as the causative agent of some diseases, such as lactose intolerance and galactosemia, or for being a by-product generated in huge amounts by the cheese industry. The study of the biochemical reactions leading to the synthesis and assimilation of lactose has provided valuable models for the understanding of biosynthetic and catabolic processes. Lactose-hydrolyzing enzymes are structurally and phylogenetically related to different types of beta-galactosidases and bacterial cellobiases involved in the enzymatic degradation of cellulose. Biotransformation of lactose, by either enzymatic or fermentative procedures, is important for different types of industrial applications in dairy and pharmaceutical industries.
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Affiliation(s)
- Ana C Adam
- Instituto de Agroquímica y Tecnología de Alimentos, Valencia, Spain
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Battad-Bernardo E, McCrindle SL, Couperwhite I, Neilan BA. Insertion of an E. coli lacZ gene in Acetobacter xylinus for the production of cellulose in whey. FEMS Microbiol Lett 2004; 231:253-60. [PMID: 14987772 DOI: 10.1016/s0378-1097(04)00007-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Revised: 12/16/2003] [Accepted: 12/21/2003] [Indexed: 11/16/2022] Open
Abstract
A mini-Tn10:lacZ:kan was inserted into a wild-type strain of Acetobacter xylinus by random transposon mutagenesis, generating a lactose-utilising and cellulose-producing mutant strain designated ITz3. Antibiotic selection plate assays and Southern hybridisation revealed that the lacZ gene was inserted once into the chromosome of strain ITz3 and was stably maintained in non-selective medium after more than 60 generations. The modified strain had, on the average, a 28-fold increase in cellulose production and a 160-fold increase in beta-galactosidase activity when grown in lactose medium. beta-Galactosidase activity is present in either lactose or sucrose medium indicating that the gene is constitutively expressed. Cellulose and beta-galactosidase production by the modified strain was also evaluated in pure and enriched whey substrates. Utilisation of lactose in whey substrate by ITz3 reached 17 g l(-1) after 4 days incubation.
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Affiliation(s)
- Evelyn Battad-Bernardo
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW 2052, Australia
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Jansen MLA, Daran-Lapujade P, de Winde JH, Piper MDW, Pronk JT. Prolonged maltose-limited cultivation of Saccharomyces cerevisiae selects for cells with improved maltose affinity and hypersensitivity. Appl Environ Microbiol 2004; 70:1956-63. [PMID: 15066785 PMCID: PMC383169 DOI: 10.1128/aem.70.4.1956-1963.2004] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2003] [Accepted: 12/22/2003] [Indexed: 11/20/2022] Open
Abstract
Prolonged cultivation (>25 generations) of Saccharomyces cerevisiae in aerobic, maltose-limited chemostat cultures led to profound physiological changes. Maltose hypersensitivity was observed when cells from prolonged cultivations were suddenly exposed to excess maltose. This substrate hypersensitivity was evident from massive cell lysis and loss of viability. During prolonged cultivation at a fixed specific growth rate, the affinity for the growth-limiting nutrient (i.e., maltose) increased, as evident from a decreasing residual maltose concentration. Furthermore, the capacity of maltose-dependent proton uptake increased up to 2.5-fold during prolonged cultivation. Genome-wide transcriptome analysis showed that the increased maltose transport capacity was not primarily due to increased transcript levels of maltose-permease genes upon prolonged cultivation. We propose that selection for improved substrate affinity (ratio of maximum substrate consumption rate and substrate saturation constant) in maltose-limited cultures leads to selection for cells with an increased capacity for maltose uptake. At the same time, the accumulative nature of maltose-proton symport in S. cerevisiae leads to unrestricted uptake when maltose-adapted cells are exposed to a substrate excess. These changes were retained after isolation of individual cell lines from the chemostat cultures and nonselective cultivation, indicating that mutations were involved. The observed trade-off between substrate affinity and substrate tolerance may be relevant for metabolic engineering and strain selection for utilization of substrates that are taken up by proton symport.
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Affiliation(s)
- Mickel L A Jansen
- Department of Biotechnology, Delft University of Technology, 2628 BC Delft, The Netherlands
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Jansen MLA, De Winde JH, Pronk JT. Hxt-carrier-mediated glucose efflux upon exposure of Saccharomyces cerevisiae to excess maltose. Appl Environ Microbiol 2002; 68:4259-65. [PMID: 12200274 PMCID: PMC124116 DOI: 10.1128/aem.68.9.4259-4265.2002] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2002] [Accepted: 06/18/2002] [Indexed: 11/20/2022] Open
Abstract
When wild-type Saccharomyces cerevisiae strains pregrown in maltose-limited chemostat cultures were exposed to excess maltose, release of glucose into the external medium was observed. Control experiments confirmed that glucose release was not caused by cell lysis or extracellular maltose hydrolysis. To test the hypothesis that glucose efflux involved plasma membrane glucose transporters, experiments were performed with an S. cerevisiae strain in which all members of the hexose transporter (HXT) gene family had been eliminated and with an isogenic reference strain. Glucose efflux was virtually eliminated in the hexose-transport-deficient strain. This constitutes experimental proof that Hxt transporters facilitate export of glucose from S. cerevisiae cells. After exposure of the hexose-transport-deficient strain to excess maltose, an increase in the intracellular glucose level was observed, while the concentrations of glucose 6-phosphate and ATP remained relatively low. These results demonstrate that glucose efflux can occur as a result of uncoordinated expression of the initial steps of maltose metabolism and the subsequent reactions in glucose dissimilation. This is a relevant phenomenon for selection of maltose-constitutive strains for baking and brewing.
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Affiliation(s)
- Mickel L A Jansen
- Kluyver Laboratory of Biotechnology, Delft University of Technology, 2628 BC Delft, The Netherlands
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25
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Ugalde U, Castrillo J. Single cell proteins from fungi and yeasts. AGRICULTURE AND FOOD PRODUCTION 2002. [DOI: 10.1016/s1874-5334(02)80008-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Rubio-Texeira M, Arévalo-Rodríguez M, Lequerica JL, Polaina J. Lactose utilization by Saccharomyces cerevisiae strains expressing Kluyveromyces lactis LAC genes. J Biotechnol 2001; 84:97-106. [PMID: 11090681 DOI: 10.1016/s0168-1656(00)00350-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Whey generated in cheese manufacture continues being an industrial problem without a satisfactory solution. Genetic modification of the yeast S. cerevisiae to obtain strains able to utilize lactose, is a prerequisite for the utilization of this yeast to convert cheese whey into useful fermentation products (i.e. biomass, heterologous protein and other recombinant products). Although the construction of S. cerevisiae Lac(+) strains has been achieved by different strategies, most of these strains have unsuitable characteristics, such as genetic instability of the Lac phenotype or diauxic growth. In previous communications we have described the construction of genetically stable strains of S. cerevisiae that assimilate lactose with a high efficiency. These strains carry multiple copies of Kluyveromyces lactis LAC4 and LAC12 genes, which code for a beta-galactosidase and a lactose permease, respectively. In this work we report additional results about the effect of gene dosage, and analyze the performance of a selected strain in the bioconversion of cheese whey. Additionally, we describe the construction of a new strain, which combines the Lac(+) phenotype with additional properties of biotechnological interest: flocculence, and the ability to hydrolyze starch.
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Affiliation(s)
- M Rubio-Texeira
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Apartado de correos 73, E46100, Valencia, Burjassot, Spain.
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Domingues L, Lima N, Teixeira JA. Alcohol production from cheese whey permeate using genetically modified flocculent yeast cells. Biotechnol Bioeng 2001; 72:507-14. [PMID: 11460240 DOI: 10.1002/1097-0290(20010305)72:5<507::aid-bit1014>3.0.co;2-u] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Alcoholic fermentation of cheese whey permeate was investigated using a recombinant flocculating Saccharomyces cerevisiae, expressing the LAC4 (coding for beta-galactosidase) and LAC12 (coding for lactose permease) genes of Kluyveromyces marxianus enabling for lactose metabolization. Data on yeast fermentation and growth on cheese whey permeate from a Portuguese dairy industry is presented. For cheese whey permeate having a lactose concentration of 50 gL(-1), total lactose consumption was observed with a conversion yield of ethanol close to the expected theoretical value. Using a continuously operating 5.5-L bioreactor, ethanol productivity near 10 g L(-1) h(-1) (corresponding to 0.45 h(-1) dilution rate) was obtained, which raises new perspectives for the economic feasibility of whey alcoholic fermentation. The use of 2-times concentrated cheese whey permeate, corresponding to 100 gL(-1) of lactose concentration, was also considered allowing for obtaining a fermentation product with 5% (w/v) alcohol.
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Affiliation(s)
- L Domingues
- Centro de Engenharia Biológica-IBQF, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal
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Adam AC, González-Blasco G, Rubio-Texeira M, Polaina J. Transformation of Escherichia coli with DNA from Saccharomyces cerevisiae cell lysates. Appl Environ Microbiol 1999; 65:5303-6. [PMID: 10583980 PMCID: PMC91720 DOI: 10.1128/aem.65.12.5303-5306.1999] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We developed a system to monitor the transfer of heterologous DNA from a genetically manipulated strain of Saccharomyces cerevisiae to Escherichia coli. This system is based on a yeast strain that carries multiple integrated copies of a pUC-derived plasmid. The bacterial sequences are maintained in the yeast genome by selectable markers for lactose utilization. Lysates of the yeast strain were used to transform E. coli. Transfer of DNA was measured by determining the number of ampicillin-resistant E. coli clones. Our results show that transmission of the Amp(r) gene to E. coli by genetic transformation, caused by DNA released from the yeast, occurs at a very low frequency (about 50 transformants per microg of DNA) under optimal conditions (a highly competent host strain and a highly efficient transformation procedure). These results suggest that under natural conditions, spontaneous transmission of chromosomal genes from genetically modified organisms is likely to be rare.
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Affiliation(s)
- A C Adam
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Apartado de Correos 73, E-46100 Burjassot, Valencia, Spain
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Abstract
A recombinant strain of baker's yeast has been constructed which can assimilate lactose efficiently. This strain has been designed to allow its propagation in whey, the byproduct resulting from cheese-making. The ability to metabolize lactose is conferred by the functional expression of two genes from Kluyveromyces lactis, LAC12 and LAC4, which encode a lactose permease and a beta-galactosidase, respectively. To make the recombinant strain more acceptable for its use in bread-making, the genetic transformation of the host baker's yeast was carried out with linear fragments of DNA of defined sequence, carrying as the only heterologous material the coding regions of the two K. lactis genes. Growth of the new strain on cheese whey affected neither the quality of bread nor the yeast gassing power. The significance of the newly developed strain is two-fold: it affords a cheap alternative to the procedure generally used for the propagation of baker's yeast, and it offers a profitable use for cheese whey.
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Affiliation(s)
- A C Adam
- Instituto de Agroquímica y Tecnología de Alimentos, Consejo Superior de Investigaciones Científicas, Apartado de Correos 73, E46100-Burjasot, Valencia, Spain
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Abstract
Bread making is one of the oldest food-manufacturing processes. However, it is only in the past few years that recombinant-DNA technology has led to dramatic changes in formulation, ingredients or processing conditions. New strains of baker's yeast that produce CO2 more rapidly, are more resistant to stress or produce proteins or metabolites that can modify bread flavour, dough rheology or shelf-life are now emerging.
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Affiliation(s)
- F Randez-Gil
- Departamento de Biotechnolog a, Instituto de Agroqu mica y Tecnolog a de Alimentos, Consejo Superior de Investigaciones Cient ficas, PO Box 73, 46100 Burjassot, Valencia, Spain
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