ABSTRACT
Degradation of 2,4,6-trinitrotoluene (TNT), a nitroaromatic explosive found in the soil and ground water, was investigated using Pseudomonas aeruginosa in in vitro experiments. Biodegradable abilitiy of this bacteria was performed with 50 and 75 mg L−1 TNT concentrations in a defined liquid medium for 96 h time period. Treatment of TNT in supernatant samples taken at 0, 6, 12, 24, 48, 72 and 96 h from agitated vessels was followed by reverse-phase high-performance liquid chromatography (HPLC). In cultures supplemented with 50 and 75 mgL−1 TNT, after 96 h of incubation 46% and 59% reduction were detected respectively. Two metabolites as degradation intermediates with nitrite release into the medium, 2,4-dinitrotoluene (2,4-DNT) and 4-aminodinitrotoluene (4-ADNT), were elucidated by thin layer chromatography (TLC) and gas chromatography-mass spectrometry (GC-MS). These findings clearly indicate that Pseudomonas aeruginosa can be used in bioremediation of TNT contaminated sites.
Subject(s)
Metabolic Networks and Pathways , Pseudomonas aeruginosa/metabolism , Trinitrotoluene/metabolism , Aniline Compounds/analysis , Biotransformation , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , Culture Media , Dinitrobenzenes/analysis , Gas Chromatography-Mass Spectrometry , Time FactorsABSTRACT
The bacterial contamination as the total aerobic bacteria, coliform and fecal coliform numbers were determined and analyzed for temperature, pH, conductivity and dissolved oxygen in seasonally collected water samples from fifteen different stations placed in Adana- Tufanbeyli road line during March 2008- January 2009. In addition, antibiotic resistance profiles of isolates were examined against frequently used antibiotics, and analyzed plasmid DNA of multiple antibiotic resistant (MAR) isolates. Total aerobic bacteria in fountain water samples was determined as 3x103 CFU ml-1 and total and fecal coliforms were determined 460 MPN/100 ml. Results obtained from biochemical analysis showed that 121 of the isolates were Proteus vulgaris, 69 Escherichia coli, 51 Pseudomonas aeruginosa and 28 Citrobacter spp. According to these results, the existence of Vibrio parahaemolyticus in stations 2 and 10, and Streptococcus faecalis in stations 11 and 15 respectively were confirmed. Clostridium perfringens was not detected in water samples. A total of 273 isolates were tested for antimicrobial susceptibility by agar disc diffusion methods. A total of sixteen antibiotics were used for determination of antibiotic resistance of isolates. Resistance to bacitracin, vancomycine, cephalothin and ampicillin was detected in 77, 77, 63 and 50%, respectively. Multiple antibiotic resistance (MAR) value > 0.25 was determined in 68.4% of identified 273 isolates and meaning of this percentage were resistant to four and more antibiotics. Plasmid DNA was isolated from 22 isolates with multiple antibiotic resistance index ranged from 0.3 to 0.6 taken randomly by agarose-gel electrophoresis, some of them contain a high-molecular weight plasmid DNA. Highlight of our study that the appearance of potential antibiotic resistances in fountain drinking water requires increased surveillance for risk assessment and prevention strategies to protect public health.
ABSTRACT
A total of 94 bacteria, associated with wild Achanthobrama marmid (Heckel, 1843) in Sir Dam lake of Turkey identified. Subsequently, selected isolates were characterized and identified to the genus level. The 94 members of Enterobacteriaceae were isolated in the gills and intestines, and among the isolates, E. coli were represented at a rate of 55 %, Shigella spp. at a rate of 21 %, Salmonella spp. at a rate of 9%, Citrobacter spp. at a rate of 9%, Klebsiella spp. at a rate of 3% and Proteus spp., at a rate of 3%. A total of 94 bacteria resistant to antibiotics and heavy metals were isolated from total 47 of A. marmid samples and were investigated. Viable counts of antibiotic resistant bacteria isolated from gill and intestinal content samples showed high frequencies of resistance to Penicilline-G (KP) (68%), CZ (54%), FOX (48%), while the proportion of CRO (39%) and CTX (36%) resistance was low. In this research, heavy metal contamination in Sir Dam lake water samples and resistance frequency against heavy metals in isolated bacteria from gill and intestinal contents in A. marmid were investigated. Heavy metal contamination such as nickel (Ni), cadmium (Cd), copper (Cu) and chromium (Cr) determined diverse rate (except Mn) in water samples. The resistance frequency of the isolates was revealed different rate for the following heavy metals: Ni, Cd, Cu and Cr. When the concentration of heavy metals increased, the resistance against heavy metals in diverse genus of isolates in different rate decreased.
ABSTRACT
An alkaliphilic and highly thermostable alpha-amylase producing Bacillus sp. was isolated from Van soda lake. Enzyme synthesis occurred at temperatures between 25ºC and 40ºC. Analysis of the enzyme by SDS-PAGE revealed a single band which was estimated to be 66 kDa. The enzyme was active in a broad temperature range, between 20ºC and 90ºC, with an optimum at 50ºC; and maximum activity was at pH 10.5. The enzyme was almost completely stable up to 80ºC with a remaining activity over 90 percent after 30 min pre-incubation. Thermostability was not increased in the presence of Ca2+. An average of 75 percent and 60ºC of remaining activity was observed when the enzyme was incubated between pH 5 and 9 for 1 h and for 2 h, respectively. The activity of the enzyme was inhibited by SDS and EDTA by 38 percent and 34 percent, respectively.
Bacillus sp AB68 alcalif¨ªlico produtor de alfa-amilase alcalina termoest¨¢vel foi isolado do lago Van soda. A s¨ªntese da enzima ocorreu entre 25ºC e 40ºC. A an¨¢lise da enzima por SDS-PAGE revelou uma ¨²nica banda estimada em 66 kDa. A enzima foi ativa em uma ampla faixa de temperatura, entre 20ºC e 90ºC, com um ¨®timo a 50ºC. A atividade m¨¢xima foi em pH 10,5. A enzima foi est¨¢vel at¨¦ 80ºC, mantendo 90 por cento de atividade ap¨®s 30 min de pr¨¦-incubação. A termoestabilidade não aumentou na presença de Ca2+. Quando incubada em pH entre 5 e 9 por 1h e por 2h, a enzima manteve 75 por cento e 60 por cento de atividade, respectivamente. SDS e EDTA causaram redução de 38 por cento e 34 por cento na atividade da enzima, respectivamente.