Ammonia oxidation capacity of bacillus bacteria in swine wastewater after biogas treatment

Nitrogen removal with biological methods plays a crucial role in wastewater treatment technology. The treatment begins with the oxidation of ammonia to nitrite to facilitate the subsequent nitrification and denitrification. Various strains of ammonia-oxidising bacteria have been reported. In this study, we use three Bacillus bacteria isolated from swine wastewater to oxidise ammonia. Different initial densities (103, 104, 105, and 106 CFU·mL–1) of each strain were examined. The results show that the combination of all the bacteria at a ratio of 1:1:1 and a density of 105 CFU·mL–1 exhibits the most effect. The findings contribute to the diversity of ammonia-oxidising bacterial species and pose a great potential for applying these strains in wastewater treatment

Nitrite metabolism of several bacterial strains isolated from abattoir and swine wastewater after biogas treatment

In nitrogen treatment with biological methods, nitrite metabolism is an intermediate process that facilitates other processes involving different bacteria strains. In this study, we isolated two nitrite-oxidising bacteria strains from abattoir wastewater and wastewater from biogas tanks of an industrial pig farm in Ha Tinh province. The bacteria strains grow, develop, and metabolise nitrite at pH 6–8 and 30–37 °C. The samples with the nitrite concentration up to 750 mg·L–1 were oxidised within four days of incubation, and the nitrite metabolism rate was proportional to the concentration of nitrite tested. Under severe conditions (salinity up to 3% NaCl, a low dissolved oxygen level of 0.1 mg·L–1), the two isolated bacterial strains exhibited their effective growth and nitrite metabolism capacity. The results enrich the database of nitrite-oxidising bacteria and are prospective in wastewater treatment

Biotransformation von Chlorbenzolen durch anaerobe Mischkulturen und einen bakteriellen Reinstamm

Chlorierte Benzole werden in vielen Prozessen angewendet und sind ubiquitär in der Umwelt nachweisbar. Sie stellen durch ihre Toxizität und ihre Persistenz eine Bedrohung für Umwelt und menschliche Gesundheit dar. Biologischer Abbau kann eine wichtige Rolle für ihren den Verbleib in der Umwelt spielen Ein äquimolares Gemisch aus 1,2,3- und 1,2,4-Trichlorbenzol, Hexachlorbenzol und 1,3,5-Trichlorbenzol wurden von Mischkulturen umgesetzt, die aus Böden aus Vietnam und Deutschlang angereichert wurden. Die Mischkulturen transformierten ein Gemisch aus 1,2,3- und 1,2,4-Trichlorbenzol zu allen drei Dichlorbenzolen, Monochlorbenzol und Benzol. Hexachlorbenzol wurde dechloriert, ohne dass dabei das hochpersistente 1,3,5-Trichlorbenzol produziert wurde. Kulturen aus Vietnam dechlorierten außerdem 1,3,5-Tri- zu 1,3-Di- und Monochlorbenzol. Die Dechlorierungsmuster blieben über sieben Transfers stabil. Eine eine kurze Sauerstoffexposition des Inokulums veränderte das Dechlorierungsmuster einer Kultur nicht. Dagegen hemmte Vancomycin in einer Konzentration von 5 mg L-1. Mit Desulfotomaculum guttoideum strain VN1 wurde ein dechlorierender Reinstamm aus den Anreicherungskulturen isoliert. Der Reinstamm dechlorierte 1,2,3-Tri-, 1,2,4-Tri- und 1,2-Dichlorbenzol. Hexa-, 1,2,4-Tri-, alle Di- und Monobrombenzol wurden zu Benzol debromiert. Die optimale Wachstums-temperatur für Stamm VN1 war 30°C, der optimale pH bei 7.3. Der Stamm war tolerant gegenüber kurzzeitiger Sauerstoffexposition aber wuchs nicht in 0.5% NaCl, 0.2 mM Na2S, 10 mg L-1 Gentamycin oder 10 mg L-1 Vancomycin. Stamm VN1 produzierte geringe Mengen H2S aus Thiosulfat aber nicht aus Sulfat oder Sulfit. Vitamine oder Acetat waren für die Kultivierung nicht notwendig. Wasserstoff wurde zur CO2–Reduktion zu Acetat aber nicht zur reduktiven Dehalogenierung verwendet. Pyruvat induzierte starkes Wachstum aber keine Dechlorierung. Glucose wurde nicht metabolisiert. Dagegen wurde Citrat als Elektronendonor für eine reduktive Dechlorierung verwendet, was auf eine kometabolische Nutzung der halogenierten Substrate hinweist.Chlorobenzenes are ubiquitous on Earth and are a big concern for the environment and human health due to their toxicity, their persistence and wide application in chemical processes. Biodegradation can play an important role to determine the fate of chlorobenzenes in the environment. A mixture of 1,2,3- and 1,2,4-trichlorobenzene, hexachlorobenzene and 1,3,5-trichlorobenzene were bio-transformed by mixed cultures enriched from dioxin-contaminated soil and sediments in Vietnam and Germany. Mixed cultures transformed a mixture of 1,2,3- and 1,2,4-trichlorobenzene to all isomers of dichlorobenzene, monochlorobenzene and benzene. Hexachlorobenzene was transformed without accumulating 1,3,5-trichlorobenzene. Only cultures from sediments in Vietnam could convert 1,3,5-trichlorobenzene to 1,3-dichlorobenzene and monochlorobenzene. Cultures were insensitive to oxygen but sensitive to cell wall antibiotics indicating that Dehalococcoides species were not responsible for dechlorination. Desulfotomaculum guttoideum strain VN1, a pure strain was isolated from a 1,2,3- and 1,2,4-trichlorobenzene dechlorinating mixed culture. It dechlorinated 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene and 1,2-dichlorobenzene. Hexabromobenzene, 1,2,4-tribromobenzene, all isomers of dibromobenzene and monobromobenzene were debrominated to benzene. The optimal temperature and pH for strain VN1’s growth were 300C and 7.3, respectively. The strain could grow and dechlorinate when briefly exposed to oxygen. However, it could not grow in medium spiked with 0.5% of NaCl or 0.2 mM of Na2S or with vancomycin or gentamicin at a concentration 10 mg L-1. Strain VN1 produced H2S from thiosulfate but not from sulfate or sulfite. Vitamins and acetate were not necessary for VN1’s growth and dechlorination. Hydrogen was an electron donor for CO2 reduction to acetate but not for dechlorination. Strain VN1 required CO2 as carbon source. Pyruvate supported strong growth of the bacterium but did not support dechlorination activity. Glucose was not used. Reversely, citrate was an electron donor for dechlorination and dechlorination occurred via co-metabolism

Ammonia oxidation capacity of bacillus bacteria in swine wastewater after biogas treatment

Nitrogen removal with biological methods plays a crucial role in wastewater treatment technology. The treatment begins with the oxidation of ammonia to nitrite to facilitate the subsequent nitrification and denitrification. Various strains of ammonia-oxidising bacteria have been reported. In this study, we use three Bacillus bacteria isolated from swine wastewater to oxidise ammonia. Different initial densities (103, 104, 105, and 106 CFU·mL–1) of each strain were examined. The results show that the combination of all the bacteria at a ratio of 1:1:1 and a density of 105 CFU·mL–1 exhibits the most effect. The findings contribute to the diversity of ammonia-oxidising bacterial species and pose a great potential for applying these strains in wastewater treatment

Nitrite metabolism of several bacterial strains isolated from abattoir and swine wastewater after biogas treatment

In nitrogen treatment with biological methods, nitrite metabolism is an intermediate process that facilitates other processes involving different bacteria strains. In this study, we isolated two nitrite-oxidising bacteria strains from abattoir wastewater and wastewater from biogas tanks of an industrial pig farm in Ha Tinh province. The bacteria strains grow, develop, and metabolise nitrite at pH 6–8 and 30–37 °C. The samples with the nitrite concentration up to 750 mg·L–1 were oxidised within four days of incubation, and the nitrite metabolism rate was proportional to the concentration of nitrite tested. Under severe conditions (salinity up to 3% NaCl, a low dissolved oxygen level of 0.1 mg·L–1), the two isolated bacterial strains exhibited their effective growth and nitrite metabolism capacity. The results enrich the database of nitrite-oxidising bacteria and are prospective in wastewater treatment