sodium-lactate and potassium-nitrate

This study was conducted to develop methods for the application of an immobilized bioluminescence strain (KG1206), preserved by deep-freezing (DF), for the monitoring of contaminated environments. The immobilized cells, preserved by DF, required approximately 2 hr for reconstitution of their activity. A large reduction in bioluminescence was observed due to the DF process; 0.07-0.58 times that of the non deep-frozen (NDF) immobilized strain. The decreased bioluminescence activity induced by the DF process was enhanced by the stimulants, sodium lactate (SL) and KNO3. However, regardless of the inducer chemical tested, the immobilized strain modified with KNO3 consistently produced greater bioluminescence than that treated with SL, in the range of 3.0-10.7 (avg. 6.7 +/- 3.69) and 1.2-4.2 (avg. 2.4 +/- 1.47) times that of control, respectively. All KNO3 treatments of contaminated groundwater samples also resulted in an increase in bioluminescence activity, but the rate of stimulation varied for each sample. Also, no strong linear correlation was observed between the bioluminescence and the total concentration of an inducer, which may related to the complex characteristics of the environmental samples. Overall, the results demonstrated the ability of immobilized genetically engineered bacteria, preserved by DF, to measure a specific group of environmental contaminants using a stimulating agent (KNO3), suggesting the potential for its preliminary application in a field-ready bioassay.

Topics: Environmental Monitoring; Freezing; Nitrates; Potassium Compounds; Pseudomonas putida; Sodium Lactate

Herein the conditions required for the stimulation of bioluminescence activity in a genetically engineered strain of Pseudomonas putida mt-2 KG1206, containing the intact TOL plasmid and a constructed plasmid with the P(m)-lux gene, are reported upon. Both sodium lactate (SL) and potassium nitrate (KNO(3)) were able to stimulate the bioluminescence activity, but a greater increase was observed with nitrogen amendment. This selected stimulant was then tested on reconstituted cells that had been preserved by deep-freezing and mixed with pure inducer solution or groundwater samples. The stimulation of bioluminescence activities for deep-frozen strain was in the range of 101-238% of the control. The effect of KNO(3) was found to be dependent on the type of inducers used and the cell conditions. In general, high bioluminescence activity was observed with groundwater samples, contaminated with high inducer compounds. However, no significant correlation was observed between the bioluminescence intensity and the total inducer concentration in the environmental samples contaminated with complex mixtures with inducers. These results should be useful when other recombinant bioluminescence strains are to be used for environmental monitoring. Overall, the results of this study demonstrate the stimulant conditions for the bioluminescence activity of genetically engineered bacteria, and suggest the potential for preliminary application of this deep-frozen engineered strain in a field-ready bioassay to conveniently detect or monitor a specific group of environmental contaminants.

Topics: Cryopreservation; Environmental Monitoring; Gene Expression Regulation, Bacterial; Genes, Reporter; Luminescent Proteins; Nitrates; Organisms, Genetically Modified; Plasmids; Potassium Compounds; Pseudomonas putida; Sodium Lactate

Studies on the biotransformation of phosphogypsum (a waste product formed in the course of the production of phosphorous fertilizers) with the use of sulfate reducing bacteria (SRB) demonstrated that it is a good source of sulfates and biogenic elements for these bacteria, though the addition of organic carbon and nitrogen is necessary. The aim of this study was to investigate the form of nitrogen and C:N ratio in the medium on the growth of SRB community in cultures containing phosphogypsum. Batch community cultures of sulfate reducing bacteria were maintained in medium with phosphogypsum (5.0 g/l), different concentrations of sodium lactate (1.6 - 9.4 g/l) and different forms (NH4CI, CO(NH2)2, KNO3) and concentrations (0 - 250 mg/l) of nitrogen. The growth of SRB was studied in the C:N ratio of from 2:1 to 300:1. It was found that: 1 - the best source of nitrogen for SRB is urea, followed by ammonium, the worst were nitrates; 2 - the bacteria were also able to grow in medium without nitrogen but their activity was then by approximately 15% lower than in optimal growth conditions; 3 - in medium with KNO3 inhibition of sulfate reduction by approx. 50% was observed; 4 - the highest reduction of nitrates (removal of nitrate) in media with phosphogypsum and nitrates was at limiting concentrations of sodium lactate. This is probably caused by the selection under these conditions (low concentration of hydrogen sulfide) of denitrifying bacteria or sulfate reducing bacteria capable of using nitrates as an electron acceptor.

Topics: Biodegradation, Environmental; Calcium Sulfate; Culture Media; Nitrates; Nitrogen; Phosphorus; Potassium Compounds; Quaternary Ammonium Compounds; Sodium Lactate; Sulfides; Sulfur-Reducing Bacteria; Urea

A synthetic medium, consisting of inorganic salts and any of a number of carbon sources, supported the aerobic growth of Paracoccus halodenitrificans when supplemented with thiamine. The same medium plus an appropriate nitrogenous oxide supported anaerobic growth when additionally supplemented with methionine. The observation that vitamin B12 or betaine replaced methionine suggested that P. halodenitrificans had a defect in the cobalamin-dependent pathway for methionine biosynthesis, as well as the inability to synthesize betaine when growing anaerobically.

Topics: Ammonium Sulfate; Betaine; Carbohydrate Metabolism; Carbohydrates; Culture Media; Ferrous Compounds; Magnesium Sulfate; Methionine; Nitrates; Paracoccus; Phosphates; Potassium Compounds; Sodium Chloride; Sodium Lactate; Thiamine; Vitamin B 12