Histamine-degrading halophilic bacteria from traditional fish sauce: Characterization of Virgibacillus campisalis TT8.5 for histamine reduction

• Published in: Journal of biotechnology 2023-03, Vol.366, p.46-53
• Main Authors: Tran, Thi Thu Hang, Nguyen, Thi Phuong Anh, Pham, Thi Diu, Nguyen, Thi Hong, Nguyen, Thi Lam Doan, Nguyen, Thi Thanh Thuy, Tran, Thi Lan Huong, Giang, Trung Khoa, Bui, Thi Thu Hien, Do, Bien-Cuong, Nguyen, Tien-Thanh, Haltrich, Dietmar, Nguyen, Hoang Anh
• Format: Article
• Language: English
• Subjects: Animals; Archaea; Archaea - metabolism; biotechnology; Codex Alimentarius; Fermentation; Fish sauce; Fishes - metabolism; Histamine; Histamine - metabolism; Histamine degradation; oxidoreductases; Sodium Chloride - pharmacology; Virgibacillus; Virgibacillus - metabolism; Virgibacillus campisalis TT8.5
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2023.03.002

Traditionally produced fish sauce can contain significant amounts of histamine. In some instances, the histamine concentration may be well above the limit recommended by the Codex Alimentarius Commission. The aim of this study was to discover new bacterial strains capable of growing under the stressful environmental conditions of fish sauce fermentation and metabolizing histamine. In this study, 28 bacterial strains were isolated from Vietnamese fish sauce products based on their ability to grow at high salt concentrations (23% NaCl) and tested for their ability to degrade histamine. Strain TT8.5 showed the highest histamine-degradation (45.1 ± 0.2% of initially 5 mM histamine within 7 days) and was identified as Virgibacillus campisalis TT8.5. Its histamine-degrading activity was shown to be localized intracellularly and the enzyme is a putative histamine dehydrogenase. The strain exhibited optimal growth and histamine-degrading activity at 37°C, pH 7%, and 5% NaCl in halophilic archaea (HA) histamine broth. It also showed pronounced histamine-degrading activity in HA histamine broth when cultivated at temperatures of up to 40 °C as well as in the presence of up to 23% NaCl. After treatment with immobilized cells, 17.6–26.9% of the initial histamine in various fish sauce products were reduced within 24 h of incubation, while no significant changes in other parameters of fish sauce quality were observed after this treatment. Our results indicate that V. campisalis TT8.5 is of potential interest to be applied in histamine degradation of traditional fish sauce. •28 bacterial strains were isolated from Vietnamese fish sauce products, in which the strain TT8.5 showed the highest histamine degrading efficiency and was identified as Virgibacillus campisalis TT8.5.•After treatment with immobilized cells of V. campisalis TT8.5, 17.6–26.9% of the initial histamine in various fish sauce products were reduced within 24 h of incubation.•Immobilized V. campisalis TT8.5 cells is of potential interest to be applied in histamine degradation of traditional fish sauce.