A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological Analyzes
<i>Ralstonia eutropha</i> H16, a metabolically versatile bacterium, has gained prominence as a microbial platform for sustainable bioproduction. While its capabilities in synthesizing single-cell proteins and biodegradable materials are well documented, comprehensive strain-level safety...
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2025-06-01
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| author | Xiaoyan You Shuxia Song Bing Li Hui Wang Le Zhang Xiangyang Li Junliang Chen Zhiguang Zhu Guoping Zhao |
| author_facet | Xiaoyan You Shuxia Song Bing Li Hui Wang Le Zhang Xiangyang Li Junliang Chen Zhiguang Zhu Guoping Zhao |
| author_sort | Xiaoyan You |
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| description | <i>Ralstonia eutropha</i> H16, a metabolically versatile bacterium, has gained prominence as a microbial platform for sustainable bioproduction. While its capabilities in synthesizing single-cell proteins and biodegradable materials are well documented, comprehensive strain-level safety evaluations remain insufficient for food-grade applications. This study systematically assessed the safety of <i>R. eutropha</i> H16 through genomic, phenotypic, and toxicological analyzes. Genomic analyzes revealed the absence or minimal presence of virulence factors and antibiotic resistance genes, aligning with microbiological safety standards. Phenotypic investigations demonstrated a limited gastric fluid tolerance (pH 2.5, survival rate 25.70% after 3 h) and intestinal fluid persistence (pH 8, 44.67% viability after 3 h), coupled with an exceptional bile salt tolerance (0.2% <i>w</i>/<i>v</i>). Antioxidant assays confirmed the fermentation broth specifically scavenges DPPH free radicals (14.60 ± 1.24 μg Trolox/mL), whereas bacterial suspensions and cell-free supernatants exhibited a strong hydroxyl radical scavenging (>90 U/mL) and superoxide anion inhibition (>100 U/L). Acute toxicity testing indicated no mortality or histopathological abnormalities, with an LD<sub>50</sub> value exceeding 1 × 10¹¹ CFU/kg. Subacute toxicity studies (28-day, 1 × 10<sup>8</sup>–1 × 10<sup>10</sup> CFU/kg) revealed no significant effects on growth, hematology, or organ function. Minor alterations in serum biochemistry might be attributed to physiological adaptation. Subacute exposure induced transient serum ALT fluctuations without hepatorenal dysfunction, while maintaining hematological parameters within physiological ranges. Collectively, these results substantiate the safety of <i>R. eutropha</i> H16 for food-related applications while underscoring the necessity of strain-specific risk assessments for industrial microbial platforms. |
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| institution | Kabale University |
| issn | 2076-2607 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | MDPI AG |
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| series | Microorganisms |
| spelling | doaj-art-4e8d2a05c2c84ffeb1650dd36cab828b2025-08-20T03:29:35ZengMDPI AGMicroorganisms2076-26072025-06-01136132310.3390/microorganisms13061323A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological AnalyzesXiaoyan You0Shuxia Song1Bing Li2Hui Wang3Le Zhang4Xiangyang Li5Junliang Chen6Zhiguang Zhu7Guoping Zhao8Henan Engineering Research Center of Food Microbiology, College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, ChinaHenan Engineering Research Center of Food Microbiology, College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, ChinaNational Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences (CAS), Tianjin 300308, ChinaNational Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences (CAS), Tianjin 300308, ChinaHenan Engineering Research Center of Food Microbiology, College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, ChinaHenan Engineering Research Center of Food Microbiology, College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, ChinaHenan Engineering Research Center of Food Microbiology, College of Food and Bioengineering, Henan University of Science and Technology, Luoyang 471023, ChinaNational Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences (CAS), Tianjin 300308, ChinaNational Center of Technology Innovation for Synthetic Biology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences (CAS), Tianjin 300308, China<i>Ralstonia eutropha</i> H16, a metabolically versatile bacterium, has gained prominence as a microbial platform for sustainable bioproduction. While its capabilities in synthesizing single-cell proteins and biodegradable materials are well documented, comprehensive strain-level safety evaluations remain insufficient for food-grade applications. This study systematically assessed the safety of <i>R. eutropha</i> H16 through genomic, phenotypic, and toxicological analyzes. Genomic analyzes revealed the absence or minimal presence of virulence factors and antibiotic resistance genes, aligning with microbiological safety standards. Phenotypic investigations demonstrated a limited gastric fluid tolerance (pH 2.5, survival rate 25.70% after 3 h) and intestinal fluid persistence (pH 8, 44.67% viability after 3 h), coupled with an exceptional bile salt tolerance (0.2% <i>w</i>/<i>v</i>). Antioxidant assays confirmed the fermentation broth specifically scavenges DPPH free radicals (14.60 ± 1.24 μg Trolox/mL), whereas bacterial suspensions and cell-free supernatants exhibited a strong hydroxyl radical scavenging (>90 U/mL) and superoxide anion inhibition (>100 U/L). Acute toxicity testing indicated no mortality or histopathological abnormalities, with an LD<sub>50</sub> value exceeding 1 × 10¹¹ CFU/kg. Subacute toxicity studies (28-day, 1 × 10<sup>8</sup>–1 × 10<sup>10</sup> CFU/kg) revealed no significant effects on growth, hematology, or organ function. Minor alterations in serum biochemistry might be attributed to physiological adaptation. Subacute exposure induced transient serum ALT fluctuations without hepatorenal dysfunction, while maintaining hematological parameters within physiological ranges. Collectively, these results substantiate the safety of <i>R. eutropha</i> H16 for food-related applications while underscoring the necessity of strain-specific risk assessments for industrial microbial platforms.https://www.mdpi.com/2076-2607/13/6/1323<i>Ralstonia eutropha</i> H16safety assessmentphenotypic analysisacute and subacute toxicity |
| spellingShingle | Xiaoyan You Shuxia Song Bing Li Hui Wang Le Zhang Xiangyang Li Junliang Chen Zhiguang Zhu Guoping Zhao A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological Analyzes Microorganisms <i>Ralstonia eutropha</i> H16 safety assessment phenotypic analysis acute and subacute toxicity |
| title | A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological Analyzes |
| title_full | A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological Analyzes |
| title_fullStr | A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological Analyzes |
| title_full_unstemmed | A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological Analyzes |
| title_short | A Comprehensive Safety Assessment of <i>Ralstonia eutropha</i> H16 for Food Applications: Integrating Genomic, Phenotypic, and Toxicological Analyzes |
| title_sort | comprehensive safety assessment of i ralstonia eutropha i h16 for food applications integrating genomic phenotypic and toxicological analyzes |
| topic | <i>Ralstonia eutropha</i> H16 safety assessment phenotypic analysis acute and subacute toxicity |
| url | https://www.mdpi.com/2076-2607/13/6/1323 |
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