Nitrogen-fixing bacteria capable of utilising kerosene hydrocarbons as a sole carbon source

2000 ◽  
Vol 42 (5-6) ◽  
pp. 407-410 ◽  
Author(s):  
J. Pérez-Vargas ◽  
H.M. Poggi-Varaldo ◽  
G. Calva-Calva ◽  
E. Ríos-Leal ◽  
R. Rodríguez-Vázquez ◽  
...  

Several nitrogen fixing consortia (NFC) were isolated from kerosene contaminated soil, where Phaseolus vulgaris plants were being cultivated. The capability of these consortia for kerosene hydrocarbons removal was investigated and demonstrated. The NFC cultivated under aerobic conditions, and kerosene as sole carbon source, effected a maximum of 75% of reduction of the total kerosene hydrocarbons. Also, from experiments conducted to evaluate their atmospheric nitrogen fixing capability, all consortia showed nitrogenase activity: from 4 to 183 nmol N2/3E09 bacteria.day. To our knowledge, this is the first report that shows a group of bacteria with the dual characteristic of fixing atmospheric nitrogen and capability to use kerosene hydrocarbons as a sole carbon source. Application of these microorganisms to soil bioremediation processes is discussed.

2002 ◽  
Vol 15 (3) ◽  
pp. 225-232 ◽  
Author(s):  
Joaquina Nogales ◽  
Rosario Campos ◽  
Hanaa BenAbdelkhalek ◽  
José Olivares ◽  
Carmen Lluch ◽  
...  

Characterization of nine transposon-induced mutants of Rhizobium tropici with decreased salt tolerance (DST) allowed the identification of eight gene loci required for adaptation to high external NaCl. Most of the genes also were involved in adaptation to hyperosmotic media and were required to overcome the toxicity of LiCl. According to their possible functions, genes identified could be classified into three groups. The first group included two genes involved in regulation of gene expression, such as ntrY, the sensor element of the bacterial ntrY/ntrX two-component regulatory system involved in regulation of nitrogen metabolism, and greA, which encodes a transcription elongation factor. The second group included genes related to synthesis, assembly, or maturation of proteins, such as alaS coding for alanine-tRNA synthetase, dnaJ, which encodes a molecular chaperone, and a nifS homolog probably encoding a cysteine desulfurase involved in the maturation of Fe-S proteins. Genes related with cellular build-up and maintenance were in the third group, such as a noeJ-homolog, encoding a mannose-1-phosphate guanylyltransferase likely involved in lipopolysaccharide biosynthesis, and kup, specifying an inner-membrane protein involved in potassium uptake. Another gene was identified that had no homology to known genes but that could be conserved in other rhizobia. When inoculated on Phaseolus vulgaris growing under nonsaline conditions, all DST mutants displayed severe symbiotic defects: ntrY and noeJ mutants were impaired in nodulation, and the remaining mutants formed symbiosis with very reduced nitrogenase activity. The results suggest that bacterial ability to adapt to hyper-osmotic and salt stress is important for the bacteroid nitrogen-fixing function inside the legume nodule and provide genetic evidence supporting the suggestion that rhizobia face severe environmental changes after their release into plant cells.


2021 ◽  
Vol 43 (3) ◽  
pp. 27-35
Author(s):  
Pham Viet Cuong ◽  
Nguyen Phuong Hoa

The bacteria capable of fixing atmospheric nitrogen were isolated from cassava cultivated soils of Vietnam. The potential isolates were identified by analyzing the 16S rRNA gene and by morphological, biochemical, cultural characteristics. The selected isolates were assigned to the species Bacillus sp. DQT2 M17, Bacillus subtilis DTAN6 M17, and Bacillus megaterium DSHB I8. The effect of culture conditions on the nitrogen-fixing activity of three selected isolates were studied and the obtained results showed that the highest amount of accumulated ammonia was detected after 6 days of incubation at 35 oC, pH 7.0 with sucrose as a carbon source. The selected strains could be exploited as inoculants for microbial fertilizer production.


Author(s):  
Y. Murtala ◽  
B. C. Nwanguma ◽  
L. U. S. Ezeanyika

Background: Despite the banned on the use of dichlorodiphenyltrichloroethane (DDT) and other Persistent Organic Pollutants (POPs) by the Stockholm Convention for their toxicity, emerging shreds of evidence have indicated that DDT is, however, still in use in developing countries. This might increase the global burden of DDT contamination and its hazardous effects. Aim: This study focused on the isolation and characterization of p,p’-DDT-degrading bacterium from a tropical agricultural soil. Methodology: Standard isolation procedure was used for the screening and isolation of the strain. The 16S rRNA and phylogenetic analyses were used to identify the isolate and established protocols were followed to characterize the strain. Results: A new strain belonging to the genus Aeromonas was isolated from agricultural soil using minimal salt-p,p’-DDT enrichment medium. The 16S rRNA sequencing was used to identify the strain and the partial sequence was deposited in the NCBI GenBank as Aeromonas sp. Strain MY1. This mesophilic isolate was capable of utilizing up to 50 mgL-1 of p,p’-DDT as the sole carbon source at an optimum pH of 7.5 and optimum temperature of 35 °C within 120 h under aerobic conditions. Fe2+ (0.2 mgL-1) demonstrated a stimulatory effect on the p,p’-DDT degradation capacity by the strain MY1. However, Zn, Cu, Pb, Hg, Ag and Cr ions have demonstrated various patterns of inhibitory effect on the p,p’-DDT degradation capacity of the isolate at 0.2 mgL-1. The strain MY1 could be a promising candidate for the bioremediation of p,p’-DDT contaminant. Conclusion: Aeromonas sp. strain MY1 was capable of utilizing p,p’-DDT as a sole carbon source under aerobic conditions. The utilization capacity of the strain was influenced by some heavy metals. Fe was found to enhance the p,p’-DDT utilization capacity of the isolate at a lower concentration. While Zn, Cu, Pb, Hg, Ag and Cr showed various patterns of inhibitory effect.


2010 ◽  
Vol 76 (24) ◽  
pp. 7972-7980 ◽  
Author(s):  
Petra R. A. Kohler ◽  
Jasmine Y. Zheng ◽  
Elke Schoffers ◽  
Silvia Rossbach

ABSTRACT The nitrogen-fixing symbiont of alfalfa, Sinorhizobium meliloti, is able to use myo-inositol as the sole carbon source. Putative inositol catabolism genes (iolA and iolRCDEB) have been identified in the S. meliloti genome based on their similarities with the Bacillus subtilis iol genes. In this study, functional mutational analysis revealed that the iolA and iolCDEB genes are required for growth not only with the myo-isomer but also for growth with scyllo- and d-chiro-inositol as the sole carbon source. An additional, hypothetical dehydrogenase of the IdhA/MocA/GFO family encoded by the smc01163 gene was found to be essential for growth with scyllo-inositol, whereas the idhA-encoded myo-inositol dehydrogenase was responsible for the oxidation of d-chiro-inositol. The putative regulatory iolR gene, located upstream of iolCDEB, encodes a repressor of the iol genes, negatively regulating the activity of the myo- and the scyllo-inositol dehydrogenases. Mutants with insertions in the iolA, smc01163, and individual iolRCDE genes could not compete against the wild type in a nodule occupancy assay on alfalfa plants. Thus, a functional inositol catabolic pathway and its proper regulation are important nutritional or signaling factors in the S. meliloti-alfalfa symbiosis.


2003 ◽  
Vol 9 (1) ◽  
pp. 27-31
Author(s):  
I Made Sudiana

Detergent contained of Linear Alkyl Sulfonate (LAS) is toxic material to human, animal and microorganism. Strain S1 isolated from detergent contaminated soil was able to grow in media with LAS as a sole carbon source. LAS degradation took place under aerobic condition, with μmax of 0.31-h, Ks = 7.75 mg/L, Vmax = 1.04 mg/L.hour-1and Km = 8.119 mg/L. Analyses of 16s rDNA revealed that S1 is belonging to Pseudomonas aeruginosa.


2004 ◽  
Vol 70 (2) ◽  
pp. 1222-1225 ◽  
Author(s):  
Carla A. Nicholson ◽  
Babu Z. Fathepure

ABSTRACT A highly enriched halophilic culture was established with benzene as the sole carbon source by using a brine soil obtained from an oil production facility in Oklahoma. The enrichment completely degraded benzene, toluene, ethylbenzene, and xylenes within 1 to 2 weeks. Also, [14C]benzene was converted to 14CO2, suggesting the culture's ability to mineralize benzene. Community structure analysis revealed that Marinobacter spp. were the dominant members of the enrichment.


1986 ◽  
Vol 32 (4) ◽  
pp. 353-358 ◽  
Author(s):  
Mary F. Lopez ◽  
Patricia Young ◽  
John G. Torrey

The carbon source requirements for the growth and nitrogen fixation of two morphologically distinct Frankia isolates were examined. Isolate ArI3 (from Alnus rubra) grew well on propionate, malate, acetate, and trehalose, and isolate CcI2 (from Casuarina cunninghamiana) grew best on pyruvate, acetate, and propionate. In general, the same carbon sources that supported growth supported both the development of vesicles and nitrogenase activity in long-term induction experiments in both isolates. However, ArI3 cultures induced on proprionate had 7 to 26 times the activity of other carbon sources and ArI3 cultures induced on acetate did not develop any detectable acetylene reduction. In a parallel set of experiments, cultures of both isolates were induced for nitrogenase activity on propionate and the resulting nitrogen fixing cultures were washed free of the organic acid by centrifugation. The washed cultures were incubated in the presence of various carbon sources to determine the ability of a particular substrate to supply energy directly for nitrogen fixation when vesicles and nitrogenase were already present. As was observed in the long-term induction experiments, pyruvate, propionate, and acetate supported the greatest activity in CcI2. Succinate and malate supported the greatest activity in ArI3, and propionate had very little stimulation of acetylene reduction. The reason for the lack of stimulation by propionate for washed cells of ArI3 was unclear but may have been due to toxic concentrations of the organic acid. In an attempt to compare the carbon utilization of ArI3 in pure culture with that in the alder symbiosis, oxygen uptake in the presence of various carbon sources of vesicles clusters isolate from Alnus rubra nodules inoculated with ArI3 was compared with the oxygen uptake of nitrogen-fixing pure cultures of ArI3. The oxygen uptake of the isolated vesicle clusters was stimulated by sucrose, trehalose, and glucose, but not by a variety of organic acids. In comparison, nitrogen-fixing pure cultures of ArI3 readily oxidized sugars and organic acids.


1991 ◽  
Vol 25 (9) ◽  
pp. 1121-1130 ◽  
Author(s):  
Srinivasa M. Dasappa ◽  
Raymond C. Loehr

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