Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity Treatments
Contaminations are challenging for monocultures, as they impact the culture conditions and thus influence the growth of the target organism and the overall biomass composition. In phycology, axenic cultures comprising a single living species are commonly strived for both basic research and industria...
Saved in:
| Main Authors: | , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
|
| Series: | Cells |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4409/14/2/136 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832588826185302016 |
|---|---|
| author | Michael Schagerl Alexander Kaptejna Fabian Polz Sameh S. Ali Shuhao Huo Joana Seneca Petra Pjevac Vera Hechtl |
| author_facet | Michael Schagerl Alexander Kaptejna Fabian Polz Sameh S. Ali Shuhao Huo Joana Seneca Petra Pjevac Vera Hechtl |
| author_sort | Michael Schagerl |
| collection | DOAJ |
| description | Contaminations are challenging for monocultures, as they impact the culture conditions and thus influence the growth of the target organism and the overall biomass composition. In phycology, axenic cultures comprising a single living species are commonly strived for both basic research and industrial applications, because contaminants reduce significance for analytic purposes and interfere with the safety and quality of commercial products. We aimed to establish axenic cultures of <i>Limnospira fusiformis</i>, known as the food additive “Spirulina”. Axenicity is strived because it ensures that pathogens or harmful microorganisms are absent and that the harvested biomass is consistent in terms of quality and composition. For the axenic treatment, we applied sterile filtration, ultrasonication, pH treatment, repeated centrifugation, and administration of antibiotics. For testing axenicity, we considered the most common verification method plate tests with Lysogeny Broth (LB) medium, which indicated axenicity after treatments were performed. In addition, we included plate tests with Reasoner’s 2A (R2A) agar and modified Zarrouk+ medium, the latter comparable to the biochemical properties of <i>L. fusiformis</i>’ cultivation medium. In contrast to LB plates, the other media, particularly Zarrouk+, indicated bacterial contamination. We conclude that LB-agar plates are inappropriate for contamination screening of extremophiles. Contamination was also verified by cultivation-independent methods like flow cytometry and 16S rRNA genome amplicon sequencing. We detected taxa of the phyla Proteobacteria, Bacteriodota, Firmicutes and to a lesser extent Verrucomicrobiota. Contaminants are robust taxa, as they survived aggressive treatments. Sequencing data suggest that some of them are promising candidates for in-depth studies to commercially exploit them. |
| format | Article |
| id | doaj-art-19bf77b69d8a44b6a3cd2869cfbc6732 |
| institution | Kabale University |
| issn | 2073-4409 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Cells |
| spelling | doaj-art-19bf77b69d8a44b6a3cd2869cfbc67322025-01-24T13:26:48ZengMDPI AGCells2073-44092025-01-0114213610.3390/cells14020136Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity TreatmentsMichael Schagerl0Alexander Kaptejna1Fabian Polz2Sameh S. Ali3Shuhao Huo4Joana Seneca5Petra Pjevac6Vera Hechtl7Department of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, A-1030 Vienna, AustriaDepartment of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, A-1030 Vienna, AustriaDepartment of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, A-1030 Vienna, AustriaBotany Department, Faculty of Science, Tanta University, Tanta 31527, EgyptSchool of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, ChinaJoint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Djerassiplatz 1, A-1030 Vienna, AustriaJoint Microbiome Facility of the Medical University of Vienna and the University of Vienna, Djerassiplatz 1, A-1030 Vienna, AustriaDepartment of Functional and Evolutionary Ecology, University of Vienna, Djerassiplatz 1, A-1030 Vienna, AustriaContaminations are challenging for monocultures, as they impact the culture conditions and thus influence the growth of the target organism and the overall biomass composition. In phycology, axenic cultures comprising a single living species are commonly strived for both basic research and industrial applications, because contaminants reduce significance for analytic purposes and interfere with the safety and quality of commercial products. We aimed to establish axenic cultures of <i>Limnospira fusiformis</i>, known as the food additive “Spirulina”. Axenicity is strived because it ensures that pathogens or harmful microorganisms are absent and that the harvested biomass is consistent in terms of quality and composition. For the axenic treatment, we applied sterile filtration, ultrasonication, pH treatment, repeated centrifugation, and administration of antibiotics. For testing axenicity, we considered the most common verification method plate tests with Lysogeny Broth (LB) medium, which indicated axenicity after treatments were performed. In addition, we included plate tests with Reasoner’s 2A (R2A) agar and modified Zarrouk+ medium, the latter comparable to the biochemical properties of <i>L. fusiformis</i>’ cultivation medium. In contrast to LB plates, the other media, particularly Zarrouk+, indicated bacterial contamination. We conclude that LB-agar plates are inappropriate for contamination screening of extremophiles. Contamination was also verified by cultivation-independent methods like flow cytometry and 16S rRNA genome amplicon sequencing. We detected taxa of the phyla Proteobacteria, Bacteriodota, Firmicutes and to a lesser extent Verrucomicrobiota. Contaminants are robust taxa, as they survived aggressive treatments. Sequencing data suggest that some of them are promising candidates for in-depth studies to commercially exploit them.https://www.mdpi.com/2073-4409/14/2/136algal culturebacterial contaminationsterilecultivationplate test |
| spellingShingle | Michael Schagerl Alexander Kaptejna Fabian Polz Sameh S. Ali Shuhao Huo Joana Seneca Petra Pjevac Vera Hechtl Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity Treatments Cells algal culture bacterial contamination sterile cultivation plate test |
| title | Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity Treatments |
| title_full | Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity Treatments |
| title_fullStr | Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity Treatments |
| title_full_unstemmed | Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity Treatments |
| title_short | Testing the Purity of <i>Limnospira fusiformis</i> Cultures After Axenicity Treatments |
| title_sort | testing the purity of i limnospira fusiformis i cultures after axenicity treatments |
| topic | algal culture bacterial contamination sterile cultivation plate test |
| url | https://www.mdpi.com/2073-4409/14/2/136 |
| work_keys_str_mv | AT michaelschagerl testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments AT alexanderkaptejna testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments AT fabianpolz testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments AT samehsali testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments AT shuhaohuo testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments AT joanaseneca testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments AT petrapjevac testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments AT verahechtl testingthepurityofilimnospirafusiformisiculturesafteraxenicitytreatments |