Microbiological analysis of the population of extremely haloalkaliphilic sulfur-oxidizing bacteria dominating in lab-scale sulfide-removing bioreactors (original) (raw)
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Environmental science & technology, 2016
After the first commercial applications of a new biological process for the removal of hydrogen sulfide (H2S) from low pressure biogas, the need arose to broaden the operating window to also enable the removal of organosulfur compounds from high pressure sour gases. In this study we have selected microorganisms from a full-scale biodesulfurization system that are capable of withstanding the presence of thiols. This full-scale unit has been in stable operation for more than 10 years. We investigated the microbial community by using high-throughput sequencing of 16S rRNA gene amplicons which showed that methanethiol gave a competitive advantage to bacteria belonging to the genera Thioalkalibacter (Halothiobacillaceae family) and Alkalilimnicola (Ectothiorhosdospiraceae family). The sulfide-oxidizing potential of the acclimatized population was investigated under elevated thiol loading rates (4.5-9.1 mM d(-1)), consisting of a mix of methanethiol, ethanethiol, and propanethiol. With th...
AMB Express, 2019
Chemolithoautotrophic sulfur-oxidizing bacteria (SOB) are crucial key players in biotechnological processes to remove hydrogen sulfide from sour gas streams. Several different haloalkaliphilic SOB have been detected and isolated from lab-and full-scale facilities, which all performed differently considering end product yields (sulfur and sulfate) and conversion rates. Understanding and regulating bacterial community dynamics in biodesulfurization processes will enable optimization of the process operation. We developed quantitative PCR (qPCR) assays to quantify haloalkaliphilic sulfur-oxidizing gammaproteobacterial species Alkalilimnicola ehrlichii, Thioalkalivibrio sulfidiphilus, and Thioalkalibacter halophilus that dominate bacterial communities of biodesulfurization lab-and full-scale installations at haloalkaline conditions. The specificity and PCR efficiency of novel primer sets were evaluated using pure cultures of these target species. We further validated the qPCR assays by quantification of target organisms in five globally distributed full-scale biodesulfurization installations. The qPCR assays perform a sensitive and accurate quantification of Alkalilimnicola ehrlichii, Thioalkalivibrio sulfidiphilus and Thioalkalibacter halophilus, thus providing rapid and valuable insights into process performance and SOB growth dynamics in gas biodesulfurization systems.
Water
A new halo-alkaline sulfur-oxidising bacterial strain was isolated from brackish estuary sediments contaminated by total petroleum hydrocarbon. The isolate was classified as a new strain of Thioalkalivibrio sulfidiphilus sp., showing a higher capability of adaptation to pH and a higher optimal sodium concentration for growth, when compared to Thioalkalivibrio sulfidiphilus sp. HL-EbGr7, type strain of the species. The strain was capable to grow in saline concentrations up to 1.5 M Na+ and pH up to 10. The genome of the new isolate was sequenced and annotated. The comparison with the genome of Thioalkalivibrio sulfidiphilus sp. HL-EbGr7 showed a duplication of an operon encoding for a putative primary sodium extruding pump and the presence of a sodium/proton antiporter with optimal efficiency at halo-alkaline conditions. The new strain was able to oxidize sulfide at halo-alkaline conditions at the rate of 1 mmol/mg-N/h, suitable for industrial applications dedicated to the recovery o...
Scientific Reports
Hydrogen sulfide (H2S) is a super toxic substance that produces SOx gases when combusted. Therefore, it should be removed from gas streams. Biodesulfurization is one of the developing methods for removing sulfide. Gas biodesulfurization must be accelerated to be competitive with chemical processes. This process has two sides: biotic and abiotic sides. To increase the rate of sulfide removal, this substance should be given to the bacteria in the maximum amount (Max. − RHS B). Therefore, it is necessary to minimize the rate of adverse abiotic reactions of sulfide (Min. − RHS A). Minimizing the sulfide reaction with biosulfur and oxygen and thiosulfate generation (Min. − RHS thio2) was assessed in de-microbized medium. It was concluded that the pH should be kept as low as possible. The kinetics of thiosulfate formation from sulfide oxidation (− RHS thio1) are strongly dependent on the sulfide concentration, and to minimize this reaction rate, sulfide should be gently injected into the ...
Extremophiles, 2004
The chemolithoautotrophic, sulfur-oxidizing bacterium Thioalkalivibrio versutus strain ALJ 15, isolated from a soda lake in Kenya, was grown in a continuous culture, with thiosulfate or polysulfide as growth-limiting energy source and oxygen as electron acceptor, at pH 10 and at pH 0.6, 2 M and 4 M total sodium. The end product of the sulfur-compound oxidation was sulfate. Elemental sulfur and a cell-bound, polysulfide-like compound appeared as intermediates during substrate oxidation. In the thiosulfate-limited culture, the biomass yields and maximum specific growth rates decreased two and three times, respectively, with increasing sodium concentration. The apparent affinity constant measured for thiosulfate and polysulfide was in the micromolar range (K s =6±3 lM). The maintenance requirement (m s =8±5 mmol S 2 O 3 2 /g dry weight h )1 ) was in the range of values found for other autotrophic sulfur-oxidizing bacteria. The organism had a comparable maximum specific rate of oxygen uptake with thiosulfate, polysulfide, and sulfide, while elemental sulfur was oxidized at a lower rate. Glycine betaine was the main organic compatible solute. The respiration rates with different species of polysulfides (S n 2) ) were tested. All polysulfide species were completely oxidized at high rates to sulfate. Overall data demonstrated efficient growth and sulfur compounds oxidation of haloalkaliphilic chemolithoautotrophic bacteria from soda lakes.
Table of contents CHAPTER 1 Introduction 1.1 Why do we need gas desulfurization? 1.2 Characteristics of hydrogen sulfide and thiols 1.3 Sulfur recovery technologies 1.4. Biotechnological sulfide removal 1.4.1. Thiopaq process concept 1.4.2. Sulfur-oxidizing bacteria 1.4.3. Thiol toxicity effect on biological sulfide oxidation 1.4.4. Control of oxygen supply to achieve higher sulfur selectivity 1.5 Aims and thesis outline References CHAPTER 2 Development and validation of a physiologically based kinetic model for starting up and operation of the biological gas desulfurization process under haloalkaline conditions 2.1 Introduction 2.2 Materials and Methods 2.2.1 Experimental setup and design 2.2.2 Biomass sources 2.2.3 Medium composition 2.2.4 Respiration test 2.2.5 Application of a physiologically based kinetic model 2.2.6 Analytical techniques 2.2.7 DNA extraction and 16S rRNA sequencing 2.3 Results 2.3.1 Biodesulfurization process performance 2.3.2 Bacterial community analyses 2.4 Discussion 2.5 Conclusions Acknowledgments References Appendix A-Nomenclature. Appendix B-Non-linear least squares estimation of the kinetic model describing biological sulfide oxidation. Appendix C-Non-linear least squares estimation of formation rates. Appendix D-Predicted sulfate and sulfur selectivities 6 | CHAPTER 3 Development of quantitative PCR for the detection of Alkalilimnicola ehrlichii, Thioalkalivibrio sulfidiphilus and Thioalkalibacter halophilus in gas biodesulfurization processes 3.
Biogas Hydrogen sulfide Wastewater treatment plant Desulfurization Oxygen uptake rate a b s t r a c t Operational experiences and strategies to get suitable chemolithoautotrophic sulfideoxidizing biomass from activated sludge wastewater treatment plant for its deploying in a full-scale biogas desulfurization plant are described. An economic nutrient source was applied to foster microbial selection and rapid growth. Respirometry was implemented on full-scale installations to monitor the ability of the specialized bacteria consortium to oxidize reduced sulfur i.e. H 2 S. During the deployment in the full-scale desulfurization reactor, intermittent sulfide feed from biogas scrubbing was performed to accelerate the startup the desulfurization process. ª ScienceDirect ht tp://www.elsevier.com/locate/biombioe b i o m a s s a n d b i o e n e r g y 6 6 ( 2 0 1 4 ) 4 6 0 e4 6 4 http://dx.
Research Article, 2012
A moderately salt-tolerant and obligately alkaliphilic, chemolithoautotrophic sulfur-oxidizing bacterium, strain HL-EbGr7 T, was isolated from a full-scale bioreactor removing H2S from biogas under oxygen-limited conditions. Another strain, ALJ17, closely related to HL-EbGr7 T , was isolated from a Kenyan soda lake. Cells of the isolates were relatively long, slender rods, motile by a polar flagellum. Although both strains were obligately aerobic, micro-oxic conditions were preferred, especially at the beginning of growth. Chemolithoautotrophic growth was observed with sulfide and thiosulfate in a pH range of 8.0–10.5 (optimum at pH 10.0) and a salinity range of 0.2–1.5 M total Na+ (optimum at 0.4 M). The genome sequence of strain HL-EbGr7 T demonstrated the presence of genes encoding the reverse Dsr pathway and a truncated Sox pathway for sulfur oxidation and enzymes of the Calvin–Benson cycle of autotrophic CO2 assimilation with ribulose-bisphosphate carboxylase/oxygenase (RuBisCO) type I. The dominant cellular fatty acids were C18 : 1 v7, C16 : 0 and C19 : 0 cyclo.
Geomicrobiology Journal, 2020
Salinity negatively affects growth of sulfur-oxidizing bacteria (SOB) and their sulfate production ability, meanwhile decreases the available sulfate for plants in soil. The aim of this study was to isolate and characterize the bacteria of genus Halothiobacillus, as a salt-tolerant SOB, from saline and sulfidic habitats of Iran for the first time and evaluating the effect of salinity on their biomass and sulfate production during the oxidation of different sulfur sources. Isolation process and surveying the morphological, biochemical and 16S rRNA gene analysis resulted into identification of three species (eight strains) of Halothiobacillus genus including H. neapolitanus, H. hydrothermalis and H. halophilus. Salinity (0, 0.5, 1, 2 and 4 M NaCl) had a significant impact (p 0.01) on bacterial biomass and sulfate production during the oxidation of thiosulfate and elemental sulfur. Biomass and sulfate production by strains was accompanied by a decrease in residual content of thiosulfate (RCT) in medium. The amount of produced biomass and sulfate in medium supplemented by thiosulfate was much higher than elemental sulfur. The highest amount of biomass and sulfate was produced by H. neapolitanus strain I19 at 0.5 and 1 M NaCl concentration. The results of this study could be the first step to focus on the application of these bacteria to increase sulfate storage of saline soils and crop production.
Disproportionation of elemental sulfur by haloalkaliphilic bacteria from soda lakes
Extremophiles, 2013
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