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Carboni G, Marova I, Zara G, Zara S, Budroni M, Mannazzu I. Evaluation of Recombinant Kpkt Cytotoxicity on HaCaT Cells: Further Steps towards the Biotechnological Exploitation Yeast Killer Toxins. Foods 2021; 10:foods10030556. [PMID: 33800189 PMCID: PMC8000969 DOI: 10.3390/foods10030556] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/24/2021] [Accepted: 02/28/2021] [Indexed: 11/16/2022] Open
Abstract
The soil yeast Tetrapisispora phaffii secretes a killer toxin, named Kpkt, that shows β-glucanase activity and is lethal to wine spoilage yeasts belonging to Kloeckera/Hanseniaspora, Saccharomycodes and Zygosaccharomyces. When expressed in Komagataella phaffii, recombinant Kpkt displays a wider spectrum of action as compared to its native counterpart, being active on a vast array of wine yeasts and food-related bacteria. Here, to gather information on recombinant Kpkt cytotoxicity, lyophilized preparations of this toxin (LrKpkt) were obtained and tested on immortalized human keratinocyte HaCaT cells, a model for the stratified squamous epithelium of the oral cavity and esophagus. LrKpkt proved harmless to HaCaT cells at concentrations up to 36 AU/mL, which are largely above those required to kill food-related yeasts and bacteria in vitro (0.25-2 AU/mL). At higher concentrations, it showed a dose dependent effect that was comparable to that of the negative control and therefore could be ascribed to compounds, other than the toxin, occurring in the lyophilized preparations. Considering the dearth of studies regarding the effects of yeast killer toxins on human cell lines, these results represent a first mandatory step towards the evaluation the possible risks associated to human intake. Moreover, in accordance with that observed on Ceratitis capitata and Musca domestica, they support the lack of toxicity of this toxin on non-target eukaryotic models and corroborate the possible exploitation of killer toxins as natural antimicrobials in the food and beverages industries.
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Affiliation(s)
- Gavino Carboni
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100 Sassari, Italy; (G.C.); (G.Z.); (S.Z.); (M.B.)
- Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Královo Pole, 61200 Brno, Czech Republic
| | - Ivana Marova
- Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Královo Pole, 61200 Brno, Czech Republic
- Correspondence: (I.M.); (I.M.)
| | - Giacomo Zara
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100 Sassari, Italy; (G.C.); (G.Z.); (S.Z.); (M.B.)
| | - Severino Zara
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100 Sassari, Italy; (G.C.); (G.Z.); (S.Z.); (M.B.)
| | - Marilena Budroni
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100 Sassari, Italy; (G.C.); (G.Z.); (S.Z.); (M.B.)
| | - Ilaria Mannazzu
- Department of Agricultural Sciences, University of Sassari, Viale Italia 39, 07100 Sassari, Italy; (G.C.); (G.Z.); (S.Z.); (M.B.)
- Correspondence: (I.M.); (I.M.)
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Carboni G, Fancello F, Zara G, Zara S, Ruiu L, Marova I, Pinna G, Budroni M, Mannazzu I. Production of a lyophilized ready-to-use yeast killer toxin with possible applications in the wine and food industries. Int J Food Microbiol 2020; 335:108883. [PMID: 32956955 DOI: 10.1016/j.ijfoodmicro.2020.108883] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/01/2020] [Accepted: 09/02/2020] [Indexed: 11/24/2022]
Abstract
Kpkt is a yeast killer toxin, naturally produced by Tetrapisispora phaffii, with possible applications in winemaking due to its antimicrobial activity on wine-related yeasts including Kloeckera/Hanseniaspora, Saccharomycodes and Zygosaccharomyces. Here, Kpkt coding gene was expressed in Komagataella phaffii (formerly Pichia pastoris) and the bioreactor production of the recombinant toxin (rKpkt) was obtained. Moreover, to produce a ready-to-use preparation of rKpkt, the cell-free supernatant of the K. phaffii recombinant killer clone was 80-fold concentrated and lyophilized. The resulting preparation could be easily solubilized in sterile distilled water and maintained its killer activity for up to six months at 4 °C. When applied to grape must, it exerted an extensive killer activity on wild wine-related yeasts while proving compatible with the fermentative activity of actively growing Saccharomyces cerevisiae starter strains. Moreover, it displayed a strong microbicidal effect on a variety of bacterial species including lactic acid bacteria and food-borne pathogens. On the contrary it showed no lethal effect on filamentous fungi and on Ceratitis capitata and Musca domestica, two insect species that may serve as non-mammalian model for biomedical research. Based on these results, bioreactor production and lyophilization represent an interesting option for the exploitation of this killer toxin that, due to its spectrum of action, may find application in the control of microbial contaminations in the wine and food industries.
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Affiliation(s)
- Gavino Carboni
- Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Francesco Fancello
- Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Giacomo Zara
- Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Severino Zara
- Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Luca Ruiu
- Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Ivana Marova
- Faculty of Chemistry, Brno University of Technology, Purkyňova 464/118, Královo Pole, 61200, Brno, Czech Republic
| | | | - Marilena Budroni
- Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari, Italy
| | - Ilaria Mannazzu
- Department of Agriculture, University of Sassari, Viale Italia 39, 07100 Sassari, Italy.
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Chessa R, Landolfo S, Ciani M, Budroni M, Zara S, Ustun M, Cakar ZP, Mannazzu I. Biotechnological exploitation of Tetrapisispora phaffii killer toxin: heterologous production in Komagataella phaffii (Pichia pastoris). Appl Microbiol Biotechnol 2016; 101:2931-2942. [PMID: 28032192 DOI: 10.1007/s00253-016-8050-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 01/27/2023]
Abstract
The use of natural antimicrobials from plants, animals and microorganisms to inhibit the growth of pathogenic and spoilage microorganisms is becoming more frequent. This parallels the increased consumer interest towards consumption of minimally processed food and 'greener' food and beverage additives. Among the natural antimicrobials of microbial origin, the killer toxin produced by the yeast Tetrapisispora phaffii, known as Kpkt, appears to be a promising natural antimicrobial agent. Kpkt is a glycoprotein with β-1,3-glucanase and killer activity, which induces ultrastructural modifications to the cell wall of yeast of the genera Kloeckera/Hanseniaspora and Zygosaccharomyces. Moreover, Kpkt maintains its killer activity in grape must for at least 14 days under winemaking conditions, thus suggesting its use against spoilage yeast in wine making and the sweet beverage industry. Here, the aim was to explore the possibility of high production of Kpkt for biotechnological exploitation. Molecular tools for heterologous production of Kpkt in Komagataella phaffii GS115 were developed, and two recombinant clones that produce up to 23 mg/L recombinant Kpkt (rKpkt) were obtained. Similar to native Kpkt, rKpkt has β-glucanase and killer activities. Moreover, it shows a wider spectrum of action with respect to native Kpkt. This includes effects on Dekkera bruxellensis, a spoilage yeast of interest not only in wine making, but also for the biofuel industry, thus widening the potential applications of this rKpkt.
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Affiliation(s)
- Rossella Chessa
- Department of Agriculture, University of Sassari, Sassari, Italy
| | - Sara Landolfo
- Department of Agriculture, University of Sassari, Sassari, Italy
| | - Maurizio Ciani
- Department of Life and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Marilena Budroni
- Department of Agriculture, University of Sassari, Sassari, Italy
- Enology and Viticulture Research Group, University of Sassari, Sassari, Italy
| | - Severino Zara
- Department of Agriculture, University of Sassari, Sassari, Italy
- Enology and Viticulture Research Group, University of Sassari, Sassari, Italy
| | - Murat Ustun
- Department of Agriculture, University of Sassari, Sassari, Italy
- Department of Molecular Biology and Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Ocalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Zeynep Petek Cakar
- Department of Molecular Biology and Genetics, Faculty of Science & Letters, Istanbul Technical University, Istanbul, Turkey
- Dr. Orhan Ocalgiray Molecular Biology, Biotechnology and Genetics Research Center (ITU-MOBGAM), Istanbul Technical University, Istanbul, Turkey
| | - Ilaria Mannazzu
- Department of Agriculture, University of Sassari, Sassari, Italy.
- Enology and Viticulture Research Group, University of Sassari, Sassari, Italy.
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