| 1. |
- Daga-Quisbert, Jeanett, et al.
(författare)
-
Analysis of the microbiome of the Bolivian high-altitude Lake Pastos Grandes
- 2023
-
Ingår i: FEMS Microbiology Ecology. - : Oxford University Press (OUP). - 0168-6496 .- 1574-6941. ; 99:8
-
Tidskriftsartikel (refereegranskat)abstract
- Lake Pastos Grandes in Bolivia is mainly composed of salt flats, which are sporadically and only partially submerged during the wet season. In the present study, the chemical composition of water samples of the lake and some influent rivers was determined. We found that it is likely that the lake was influenced by the dilution of metals from ancient evaporites. We performed the first metagenomic studies of this lake. Analyses of shotgun metagenomics revealed that the relative abundances of Burkholderiales and Pseudomonadales were noteworthy in the water samples, whereas the archaea belonging to the Halobacteriales and Cyanobacteria from subsection III had high abundances in the salt flat. The eukaryotes Crustacea and Diatomea exhibited the highest abundances in the water samples. We investigated further the potential effect of human activities on the nitrogen cycle mobilization in the lake and the propagation of antimicrobial resistance genes. This is the first report about the cycle in the lake. Additionally, rifamycin resistance genes and genes related to efflux pumps, which are not considered a hazard when identified in metagenomes, had the uppermost relative abundances in all sampling points. We found that Lake Pastos Grandes hitherto does not show an appreciable influence by anthropogenic actions. The microbiome of Lake Pastos Grandes, including microbial distribution, the nitrogen cycle and antibiotic resistance genes, was analyzed.
|
|
| 2. |
- Daga-Quisbert, Jeanett, et al.
(författare)
-
Assessing water quality of a hypereutrophic alkaline urban lake and its coagulation-treated water using metagenomic analysis
- 2024
-
Ingår i: Water, Air and Soil Pollution. - : Springer Nature. - 0049-6979 .- 1573-2932. ; 235:6
-
Tidskriftsartikel (refereegranskat)abstract
- The study on Lake Alalay, an urban alkaline lake facing increasing pollution, focused on the impact of coagulation treatment on its water quality and microbiome. The findings revealed higher nutrient concentrations, specifically phosphate and ammonium, compared to the 2019 benchmark. The lake was found to be dominated by Proteobacteria, followed by Cyanobacteria, with Desulfobacterota thriving in areas with low dissolved oxygen. Arthrospira and Roseobacter, halo-alkali-tolerant photosynthetic bacterial genera, were detected at all sampling points. Local phosphate and oxygen concentration variations led to distinct microbial communities on the lake's surface. Despite these differences, long-term ex-situ studies on water treatment with iron chloride and poly-aluminum chloride reduced the relative abundance of Cyanobacteria, promoting the presence of Proteobacteria and Bacteroidota. However, the coagulants required higher quantities than those typically used in small shallow lakes to precipitate phosphate and improve water quality effectively. Furthermore, the large-scale assay of lake water treatment with coagulants failed to eliminate Vibrio and Acinetobacter multidrug-resistant bacteria. In conclusion, the study underscores the need to prevent the inflow of polluted water into Lake Alalay and implement effective measures to deal with the existing chemical and biological contamination.
|
|
| 3. |
- Ljungqvist, Emil E., et al.
(författare)
-
Insights into the rapid metabolism of Geobacillus sp. LC300 : unraveling metabolic requirements and optimal growth conditions
- 2024
-
Ingår i: Extremophiles. - : Springer Nature. - 1431-0651 .- 1433-4909. ; 28:1
-
Tidskriftsartikel (refereegranskat)abstract
- This study investigated the metabolism of Geobacillus sp. LC300, a promising biorefinery host organism with high substrate utilization rates. A new defined medium was designed and tested that allows for exponential growth to elevated cell densities suitable for quantitative physiological studies. Screening of the metabolic requirements of G. sp. LC300 revealed prototrophy for all essential amino acids and most vitamins and only showed auxotrophy for vitamin B12 and biotin. The effect of temperature and pH on growth rate was investigated, adjusting the optimal growth temperature to several degrees lower than previously reported. Lastly, studies on carbon source utilization revealed a capability for fast growth on several common carbon sources, including monosaccharides, oligosaccharides, and polysaccharides, and the highest ever reported growth rate in defined medium on glucose (2.20 h(-1)) or glycerol (1.95 h(-1)). These findings provide a foundation for further exploration of G. sp. LC300's physiology and metabolic regulation, and its potential use in bioproduction processes.
|
|
| 4. |
- Ortiz-Veizan, Nancy, et al.
(författare)
-
Improvements of poly(3-hydroxybutyrate) production in an air-lift reactor using simple production media
- 2020
-
Ingår i: Bioresources And Bioprocessing. - : Springer. - 2197-4365. ; 7:1
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Halomonas boliviensis is a halophilic microorganism that accumulates poly(3-hydroxybutyrate) (PHB) using different carbons sources when nitrogen is depleted from the culture medium. This work presents an improved production of PHB using an air-lift reactor (ALR) that was fed with a concentrated solution of a carbon source, and was supplemented with an adequate airflow rate. Results: Simple production media were used to study PHB production by H. boliviensis in an ALR. Glucose was first used as the main carbon source and was fed during the exponential phase of cell growth. The maximum CDW and PHB content were 31.7 g/L and 51 wt%, respectively, when the airflow rate entering the reactor varied between 0.5 and 1.2 L/min. Changing the air inflow to 0.5-0.9 L/min resulted in an improvement in PHB accumulation (62 wt%). A cultivation was performed by using the latter range of airflow rate and feeding glucose only when nitrogen was depleted from the medium; a considerable enhancement in PHB content (72 wt%) and CDW (27 g/L) was achieved under these conditions. Moreover, PHB was also produced using molasses as the main carbon source. Residual cell mass was about the same to that achieved with glucose, however the PHB content (52 wt%) was lower. Conclusions: PHB production by H. boliviensis in an ALR using a simple medium is possible. CDW and PHB content in H. boliviensis can be improved with respect to batch cultivations previously reported when a carbon source is fed to the reactor. The best strategy for the production of PHB consisted of starting the cultivation in a batch mode while glutamate was present in the medium; glucose should be fed when glutamate is depleted from the medium to keep an excess of the carbon source during the synthesis of PHB.
|
|
