The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Damien John Batstone - One of the best experts on this subject based on the ideXlab platform.
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purple Phototrophic Bacteria are outcompeted by aerobic heterotrophs in the presence of oxygen
Water Research, 2021Co-Authors: Gabriel Capsontojo, Damien John Batstone, Shengli Lin, Tim HulsenAbstract:Abstract There is an ongoing debate around the effect of microaerobic/aerobic conditions on the wastewater treatment performance and stability of enriched purple Phototrophic Bacteria (PPB) cultures. It is well known that oxygen-induced oxidative conditions inhibit the synthesis of light harvesting complexes, required for photoheterotrophy. However, in applied research, several publications have reported efficient wastewater treatment at high dissolved oxygen (DO) levels. This study evaluated the impact of different DO concentrations (0-0.25 mg·L−1, 0-0.5 mg·L−1 and 0-4.5 mg·L−1) on the COD, nitrogen and phosphorus removal performances, the biomass yields, and the final microbial communities of PPB-enriched cultures, treating real wastewaters (domestic and poultry processing wastewater). The results show that the presence of oxygen suppressed photoheterotrophic growth, which led to a complete pigment and colour loss in a matter of 20-30 h after starting the batch. Under aerobic conditions, chemoheterotrophy was the dominant catabolic pathway, with wastewater treatment performances similar to those achieved in common aerobic reactors, rather than those corresponding to Phototrophic systems (i.e. considerable total COD decrease (45-57% aerobically vs. ± 10% anaerobically). This includes faster consumption of COD and nutrients, lower nutrient removal efficiencies (50-58% vs. 72-99% for NH4+-N), lower COD:N:P substrate ratios (100:4.5-5.0:0.4-0.8 vs. 100:6.7-12:0.9-1.2), and lower apparent biomass yields (0.15-0.31 vs. 0.8-1.2 g CODbiomass·g CODremoved−1)). The suppression of photoheterotrophy inevitably resulted in a reduction of the relative PPB abundances in all the aerated tests (below 20% at the end of the tests), as PPB lost their main competitive advantage against competing aerobic heterotrophic microbes. This was explained by the lower aerobic PPB growth rates (2.4 d−1 at 35 °C) when compared to common growth rates for aerobic heterotrophs (6.0 d−1 at 20 °C). Therefore, PPB effectively outcompete other microbes under illuminated-anaerobic conditions, but not under aerobic or even micro-aerobic conditions, as shown by continuously aerated tests controlled at undetectable DO levels. While their aerobic heterotrophic capabilities provide some resilience, at non-sterile conditions PPB cannot dominate when growing chemoheterotrophically, and will be outcompeted.
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purple Phototrophic Bacteria granules under high and low upflow velocities
Water Research, 2021Co-Authors: Samuel Stegman, Damien John Batstone, Rene A Rozendal, Paul Jensen, Tim HulsenAbstract:Abstract The application of granular biomass has enabled energy efficient, high-rate wastewater treatment systems. While initially designed for high-strength wastewater treatment, granular systems can also play a major role in resource recovery. This study focused on the formation of purple Phototrophic Bacteria (PPB) granular biomass during synthetic wastewater treatment. Liquid upflow velocity was applied as the driving force for granulation. Separate reactors were operated at either low (2-5m h−1) or high (6-9m h−1) upflow velocities, with sludge retention times (SRTs) ranging from 5-15d. Reactors produced anaerobic, photo-granules within ~50d. The sludge volume index (SVI30) of the granules was 10mL g−1 and average settling rates were greater than 30m h−1, both metrics being similar to existing granular technologies. Granule sizes of 2-3mm were recorded, however the particle size distribution was bimodal with a large floc fraction (70-80% volume fraction). The extracellular polymeric substance (EPS) and alginate-like extract (ALE) contents were similar to those in aerobic granular biomass. Fluorescence in-situ hybridisation (FISH) imaging identified PPB Bacteria dispersed throughout the granules with very few methanogens and an active core. Outer layer morphology was substantially different in the two reactors. The high-upflow reactor had an outer layer of Chromatiales and an inner layer of RhodoBacteriales, while the low-upflow reactor had lower abundances of both, and limited layering. According to 16s gene sequencing, PPB were a similar fraction of the microbial community in both reactors (40-70%), but the high upflow granules were dominated by Chromatiales (supporting FISH results), while the low upflow velocity reactor had a more diverse PPB community. Methanogens were seen only in the low upflow granules and only in small amounts (≤8%). Granule crude protein content was ~0.60gCP gVS−1 (~0.45gCP gTS−1), similar to that from other PPB production technologies. The growth of a rapid settling and discrete PPB granular biomass on synthetic wastewater suggests methods for resource recovery using PPB can be diversified to also include granular biomass.
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anaerobic digestion of purple Phototrophic Bacteria the release step of the partition release recover concept
Bioresource Technology, 2020Co-Authors: Tim Hulsen, Daniel Puyol, Ivan Rodriguez, Yolanda Segura, Fernando J Martinez, Damien John BatstoneAbstract:Purple Phototrophic Bacteria (PPB) have been proposed as a high-growth, assimilative option for wastewater treatment. The original partition-release-recover concept proposal requires their near complete digestion and release (and subsequent recovery) of energy and nutrients in an anaerobic digester. While the growth (partition) step has been extensively assessed, no work has been done on their anaerobic digestion characteristics (release). Continuous mesophilic (20d) and thermophilic (10d) digestion could achieve around 55% volatile solids degradation (VSD), with 35% (mesophilic) and 20% (thermophilic) nitrogen solubilisation. Post digestion (with/without pretreatment) could increase the VSD to 70% and nitrogen solubilisation to 43%. A number of pretreatment options were tested, with high temperature and sonication being relatively effective, and chemical treatment, and temperature phased digestion being relatively ineffective vs controls. Overall, anaerobic digestion of PPB results in substantial residual particulate material, with an increased nitrogen content, and avenues to effectively utilise this residue should be identified.
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purple Phototrophic Bacteria as a platform to create the next generation of wastewater treatment plants energy and resource recovery
2020Co-Authors: Daniel Puyol, Tim Hulsen, Fernando J Martinez, Juan A Melero, V M Monsalvo, E Marin, F Rogalla, Damien John BatstoneAbstract:New trends in wastewater treatment are addressing energy and resource recovery in holistic platforms. These include upstream and downstream procedures, and try to address energy neutrality, or at least economic profitability. Purple Phototrophic Bacteria (PPB) are emerging as a core for photo-assisted biological processes for these purposes. The high metabolic versatility and potential applications of these fascinating microorganisms have turned them into one of the most promising alternatives in wastewater biorefinery platforms. This chapter analyzes the main factors causing the growth of PPB technologies in environmental technology research groups all over the world. The metabolism of these Bacteria is overviewed, including modeling. Finally, the chapter reviews the main achievements in both domestic as well as industrial wastewater treatment with these microorganisms, especially focused on resource recovery and scaling up.
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saline wastewater treatment with purple Phototrophic Bacteria
Water Research, 2019Co-Authors: Tim Hulsen, Kent Hsieh, Damien John BatstoneAbstract:Abstract Biological removal of organics, nitrogen and from saline wastewaters is adversely impacted by high salinity, which can be a major concern for treatment of industrial or domestic saline wastewater. In anaerobic treatment systems, sulfidogensis, especially when treating sulfate-rich saline wastewaters (e.g. seawater has 930 mgSO4-S L−1, or 2800 mg L−1 as SO42−) can cause additional biological, operational, and safety issues, due to H2S toxicity. Here, the use of anaerobic purple Phototrophic Bacteria (PPB) is tested as mediator to treat high salinity domestic wastewater (NaCl), and marine wastewater (Red Sea Salt - high sulfate, potassium, etc.) in a continuous anaerobic infra-red photo bioreactor, operated over 372d. Saline adapted PPB simultaneously removed COD, nitrogen and phosphorus with biomass yields of 0.8 gCOD gCOD−1. Batch activity tests found a broad optimum peak for saline adapted PPB between 30 and 70 mS cm−1, and 50% reduced activity at 140 mS cm−1 (3.5x seawater). For marine wastewater, high sulfate influent concentrations (770 mgSO4-S L−1) did not result in substantial H2S production ( 90 mgS L−1 and the process failed. The results indicate rapid adaptation to high-salt conditions (both NaCl and marine), and the capacity for PPB to form a combined wastewater treatment/resource recovery process, particularly for salty industrial wastewater.
Tim Hulsen - One of the best experts on this subject based on the ideXlab platform.
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purple Phototrophic Bacteria are outcompeted by aerobic heterotrophs in the presence of oxygen
Water Research, 2021Co-Authors: Gabriel Capsontojo, Damien John Batstone, Shengli Lin, Tim HulsenAbstract:Abstract There is an ongoing debate around the effect of microaerobic/aerobic conditions on the wastewater treatment performance and stability of enriched purple Phototrophic Bacteria (PPB) cultures. It is well known that oxygen-induced oxidative conditions inhibit the synthesis of light harvesting complexes, required for photoheterotrophy. However, in applied research, several publications have reported efficient wastewater treatment at high dissolved oxygen (DO) levels. This study evaluated the impact of different DO concentrations (0-0.25 mg·L−1, 0-0.5 mg·L−1 and 0-4.5 mg·L−1) on the COD, nitrogen and phosphorus removal performances, the biomass yields, and the final microbial communities of PPB-enriched cultures, treating real wastewaters (domestic and poultry processing wastewater). The results show that the presence of oxygen suppressed photoheterotrophic growth, which led to a complete pigment and colour loss in a matter of 20-30 h after starting the batch. Under aerobic conditions, chemoheterotrophy was the dominant catabolic pathway, with wastewater treatment performances similar to those achieved in common aerobic reactors, rather than those corresponding to Phototrophic systems (i.e. considerable total COD decrease (45-57% aerobically vs. ± 10% anaerobically). This includes faster consumption of COD and nutrients, lower nutrient removal efficiencies (50-58% vs. 72-99% for NH4+-N), lower COD:N:P substrate ratios (100:4.5-5.0:0.4-0.8 vs. 100:6.7-12:0.9-1.2), and lower apparent biomass yields (0.15-0.31 vs. 0.8-1.2 g CODbiomass·g CODremoved−1)). The suppression of photoheterotrophy inevitably resulted in a reduction of the relative PPB abundances in all the aerated tests (below 20% at the end of the tests), as PPB lost their main competitive advantage against competing aerobic heterotrophic microbes. This was explained by the lower aerobic PPB growth rates (2.4 d−1 at 35 °C) when compared to common growth rates for aerobic heterotrophs (6.0 d−1 at 20 °C). Therefore, PPB effectively outcompete other microbes under illuminated-anaerobic conditions, but not under aerobic or even micro-aerobic conditions, as shown by continuously aerated tests controlled at undetectable DO levels. While their aerobic heterotrophic capabilities provide some resilience, at non-sterile conditions PPB cannot dominate when growing chemoheterotrophically, and will be outcompeted.
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purple Phototrophic Bacteria granules under high and low upflow velocities
Water Research, 2021Co-Authors: Samuel Stegman, Damien John Batstone, Rene A Rozendal, Paul Jensen, Tim HulsenAbstract:Abstract The application of granular biomass has enabled energy efficient, high-rate wastewater treatment systems. While initially designed for high-strength wastewater treatment, granular systems can also play a major role in resource recovery. This study focused on the formation of purple Phototrophic Bacteria (PPB) granular biomass during synthetic wastewater treatment. Liquid upflow velocity was applied as the driving force for granulation. Separate reactors were operated at either low (2-5m h−1) or high (6-9m h−1) upflow velocities, with sludge retention times (SRTs) ranging from 5-15d. Reactors produced anaerobic, photo-granules within ~50d. The sludge volume index (SVI30) of the granules was 10mL g−1 and average settling rates were greater than 30m h−1, both metrics being similar to existing granular technologies. Granule sizes of 2-3mm were recorded, however the particle size distribution was bimodal with a large floc fraction (70-80% volume fraction). The extracellular polymeric substance (EPS) and alginate-like extract (ALE) contents were similar to those in aerobic granular biomass. Fluorescence in-situ hybridisation (FISH) imaging identified PPB Bacteria dispersed throughout the granules with very few methanogens and an active core. Outer layer morphology was substantially different in the two reactors. The high-upflow reactor had an outer layer of Chromatiales and an inner layer of RhodoBacteriales, while the low-upflow reactor had lower abundances of both, and limited layering. According to 16s gene sequencing, PPB were a similar fraction of the microbial community in both reactors (40-70%), but the high upflow granules were dominated by Chromatiales (supporting FISH results), while the low upflow velocity reactor had a more diverse PPB community. Methanogens were seen only in the low upflow granules and only in small amounts (≤8%). Granule crude protein content was ~0.60gCP gVS−1 (~0.45gCP gTS−1), similar to that from other PPB production technologies. The growth of a rapid settling and discrete PPB granular biomass on synthetic wastewater suggests methods for resource recovery using PPB can be diversified to also include granular biomass.
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anaerobic digestion of purple Phototrophic Bacteria the release step of the partition release recover concept
Bioresource Technology, 2020Co-Authors: Tim Hulsen, Daniel Puyol, Ivan Rodriguez, Yolanda Segura, Fernando J Martinez, Damien John BatstoneAbstract:Purple Phototrophic Bacteria (PPB) have been proposed as a high-growth, assimilative option for wastewater treatment. The original partition-release-recover concept proposal requires their near complete digestion and release (and subsequent recovery) of energy and nutrients in an anaerobic digester. While the growth (partition) step has been extensively assessed, no work has been done on their anaerobic digestion characteristics (release). Continuous mesophilic (20d) and thermophilic (10d) digestion could achieve around 55% volatile solids degradation (VSD), with 35% (mesophilic) and 20% (thermophilic) nitrogen solubilisation. Post digestion (with/without pretreatment) could increase the VSD to 70% and nitrogen solubilisation to 43%. A number of pretreatment options were tested, with high temperature and sonication being relatively effective, and chemical treatment, and temperature phased digestion being relatively ineffective vs controls. Overall, anaerobic digestion of PPB results in substantial residual particulate material, with an increased nitrogen content, and avenues to effectively utilise this residue should be identified.
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purple Phototrophic Bacteria as a platform to create the next generation of wastewater treatment plants energy and resource recovery
2020Co-Authors: Daniel Puyol, Tim Hulsen, Fernando J Martinez, Juan A Melero, V M Monsalvo, E Marin, F Rogalla, Damien John BatstoneAbstract:New trends in wastewater treatment are addressing energy and resource recovery in holistic platforms. These include upstream and downstream procedures, and try to address energy neutrality, or at least economic profitability. Purple Phototrophic Bacteria (PPB) are emerging as a core for photo-assisted biological processes for these purposes. The high metabolic versatility and potential applications of these fascinating microorganisms have turned them into one of the most promising alternatives in wastewater biorefinery platforms. This chapter analyzes the main factors causing the growth of PPB technologies in environmental technology research groups all over the world. The metabolism of these Bacteria is overviewed, including modeling. Finally, the chapter reviews the main achievements in both domestic as well as industrial wastewater treatment with these microorganisms, especially focused on resource recovery and scaling up.
-
saline wastewater treatment with purple Phototrophic Bacteria
Water Research, 2019Co-Authors: Tim Hulsen, Kent Hsieh, Damien John BatstoneAbstract:Abstract Biological removal of organics, nitrogen and from saline wastewaters is adversely impacted by high salinity, which can be a major concern for treatment of industrial or domestic saline wastewater. In anaerobic treatment systems, sulfidogensis, especially when treating sulfate-rich saline wastewaters (e.g. seawater has 930 mgSO4-S L−1, or 2800 mg L−1 as SO42−) can cause additional biological, operational, and safety issues, due to H2S toxicity. Here, the use of anaerobic purple Phototrophic Bacteria (PPB) is tested as mediator to treat high salinity domestic wastewater (NaCl), and marine wastewater (Red Sea Salt - high sulfate, potassium, etc.) in a continuous anaerobic infra-red photo bioreactor, operated over 372d. Saline adapted PPB simultaneously removed COD, nitrogen and phosphorus with biomass yields of 0.8 gCOD gCOD−1. Batch activity tests found a broad optimum peak for saline adapted PPB between 30 and 70 mS cm−1, and 50% reduced activity at 140 mS cm−1 (3.5x seawater). For marine wastewater, high sulfate influent concentrations (770 mgSO4-S L−1) did not result in substantial H2S production ( 90 mgS L−1 and the process failed. The results indicate rapid adaptation to high-salt conditions (both NaCl and marine), and the capacity for PPB to form a combined wastewater treatment/resource recovery process, particularly for salty industrial wastewater.
Vladimir Yurkov - One of the best experts on this subject based on the ideXlab platform.
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The photosynthetic apparatus and photoinduced electron transfer in the aerobic Phototrophic Bacteria Roseicyclus mahoneyensis and Porphyrobacter meromictius
Photosynthesis Research, 2012Co-Authors: Christopher Rathgeber, Jean Alric, Elizabeth Hughes, André Verméglio, Vladimir YurkovAbstract:Photosynthetic electron transfer has been examined in whole cells, isolated membranes and in partially purified reaction centers (RCs) of Roseicyclus mahoneyensis , strain ML6 and Porphyrobacter meromictius , strain ML31, two species of obligate aerobic anoxygenic Phototrophic Bacteria. Photochemical activity in strain ML31 was observed aerobically, but the photosynthetic apparatus was not functional under anaerobic conditions. In strain ML6 low levels of photochemistry were measured anaerobically, possibly due to incomplete reduction of the primary electron acceptor (Q_A) prior to light excitation, however, electron transfer occurred optimally under low oxygen conditions. Photoinduced electron transfer involves a soluble cytochrome c in both strains, and an additional reaction center (RC)-bound cytochrome c in ML6. The redox properties of the primary electron donor (P) and Q_A of ML31 are similar to those previously determined for other aerobic phototrophs, with midpoint redox potentials of +463 mV and −25 mV, respectively. Strain ML6 showed a very narrow range of ambient redox potentials appropriate for photosynthesis, with midpoint redox potentials of +415 mV for P and +94 mV for Q_A. Cytoplasm soluble and photosynthetic complex bound cytochromes were characterized in terms of apparent molecular mass. Fluorescence excitation spectra revealed that abundant carotenoids not intimately associated with the RC are not involved in photosynthetic energy conservation.
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Aerobic Phototrophic Bacteria: New Evidence for the Diversity, Ecological Importance and Applied Potential of this Previously Overlooked Group
Photosynthesis Research, 2004Co-Authors: Christopher Rathgeber, J. Thomas Beatty, Vladimir YurkovAbstract:The aerobic Phototrophic Bacteria are a recently discovered group capable of producing a photosynthetic apparatus similar to that of purple Phototrophic Bacteria. However, this apparatus, in contrast to that of their anaerobic counterparts, is functional in terms of photoinduced electron transport only under aerobic conditions. Although these Bacteria have been widely studied, little is yet known about their ecological importance, and why they differ from other anoxygenic phototrophs with respect to oxygen requirements. In recent years a large number of new genera and species have been described from a wide variety of habitats, and evidence has been presented to support their important ecological role. This minireview focuses on recent discoveries regarding taxonomy, ecology and physiology, as well as the latest advances in the understanding of their photosynthetic apparatus and its genetic regulation.
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Diversity, distribution and physiology of the aerobic Phototrophic Bacteria in the mixolimnion of a meromictic lake
FEMS microbiology ecology, 2002Co-Authors: Natalia Yurkova, Christopher Rathgeber, Jolantha Swiderski, Erko Stackebrandt, J. Thomas Beatty, Ken J. Hall, Vladimir YurkovAbstract:The population of anoxygenic Phototrophic Bacteria in the aerobic zone of the meromictic Mahoney Lake was investigated using classical microbiological methods. This Bacterial community was found to be very rich and diverse. Thirty-one new strains of the obligately aerobic Phototrophic Bacteria, and two new purple nonsulfur strains, were isolated in pure cultures and preliminarily characterized. The isolates contain a variety of carotenoids, bacteriochlorophyll a incorporated into pigment protein complexes, and are morphologically and physiologically diverse. These properties indicate a diversity of adaptations to the stratified environments of this meromictic lake. Phylogenetically all isolated strains belong to the α subclass of ProteoBacteria.
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aerobic anoxygenic Phototrophic Bacteria
Microbiology and Molecular Biology Reviews, 1998Co-Authors: Vladimir Yurkov, Thomas J BeattyAbstract:The aerobic anoxygenic Phototrophic Bacteria are a relatively recently discovered Bacterial group. Although taxonomically and phylogenetically heterogeneous, these Bacteria share the following distinguishing features: the presence of bacteriochlorophyll a incorporated into reaction center and light-harvesting complexes, low levels of the photosynthetic unit in cells, an abundance of carotenoids, a strong inhibition by light of bacteriochlorophyll synthesis, and the inability to grow photosynthetically under anaerobic conditions. Aerobic anoxygenic Phototrophic Bacteria are classified in two marine (Erythrobacter and Roseobacter) and six freshwater (Acidiphilium, Erythromicrobium, Erythromonas, Porphyrobacter, Roseococcus, and Sandaracinobacter) genera, which phylogenetically belong to the α-1, α-3, and α-4 subclasses of the class ProteoBacteria. Despite this phylogenetic information, the evolution and ancestry of their photosynthetic properties are unclear. We discuss several current proposals for the evolutionary origin of aerobic Phototrophic Bacteria. The closest phylogenetic relatives of aerobic Phototrophic Bacteria include facultatively anaerobic purple nonsulfur Phototrophic Bacteria. Since these two Bacterial groups share many properties, yet have significant differences, we compare and contrast their physiology, with an emphasis on morphology and photosynthetic and other metabolic processes.
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Photoinduced electron transfer and cytochrome content in obligate aerobic Phototrophic Bacteria from genera Erythromicrobium, Sandaracinobacter, Erythromonas, Roseococcus and Erythrobacter
Photosynthesis Research, 1998Co-Authors: Vladimir Yurkov, Barbara Schoepp, André VerméglioAbstract:The photosynthetic apparatus and the electron carriers of seven species of five different genera of obligate aerobic Phototrophic Bacteria have been characterized by biochemical and biophysical techniques. A tetrahemic reaction center (RC) bound cytochrome (cyt) was found in Erythromonas (Em.) ursincola, Sandaracinobacter (S.) sibiricus and Roseococcus (R.) thiosulfatophilus, but not in Erythromicrobium (E.) ezovicum, Erythromicrobium ramosum, Erythromicrobium hydrolyticum and Erythrobacter (Eb.) litoralis. In none of the studied species, photochemical activity was observed under anaerobic conditions. Under aerobic conditions, the photoinduced cyclic electron transfer involves a soluble c-type cyt for the seven species. The cyt content of soluble and membrane fractions is highly dependent upon the species. The Erythromicrobium species (E. ezovicum, E. ramosum and E. hydrolyticum) contains a major soluble cyt while the other species possess several soluble cyts, up to four in the case of Eb. litoralis. These cyts have been characterized in terms of midpoint potential and apparent molecular mass. The presence of cyt bc_1 complexes has been clearly detected in Eb. litoralis, E. hydrolyticum, E. ezovicum and E. ramosum. These last three species also contain a high midpoint potential (350 mV) membrane-bound cyt c of unknown function.
Nianzhi Jiao - One of the best experts on this subject based on the ideXlab platform.
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draft genome sequences of two marine Phototrophic Bacteria erythrobacter longus strain dsm 6997 and erythrobacter litoralis strain dsm 8509
Genome Announcements, 2014Co-Authors: Yu Wang, Rui Zhang, Qiang Zheng, Nianzhi JiaoAbstract:Aerobic anoxygenic Phototrophic Bacteria (AAPB) are important functional groups and are widely distributed in the global upper ocean. Here we report the draft genomic sequences of two marine AAPB isolates belonging to the genus Erythrobacter, Erythrobacter longus strain DSM 6997 and Erythrobacter litoralis strain DSM 8509.
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formation of polyhydroxyalkanoate in aerobic anoxygenic Phototrophic Bacteria and its relationship to carbon source and light availability
Applied and Environmental Microbiology, 2011Co-Authors: Na Xiao, Nianzhi JiaoAbstract:Aerobic anoxygenic Phototrophic Bacteria (AAPB) are unique players in carbon cycling in the ocean. Cellular carbon storage is an important mechanism regulating the nutrition status of AAPB but is not yet well understood. In this paper, six AAPB species (Dinoroseobacter sp. JL1447, Roseobacter denitrificans OCh 114, Roseobacter litoralis OCh 149, Dinoroseobacter shibae DFL 12(T), Labrenzia alexandrii DFL 11(T), and Erythrobacter longus DSMZ 6997) were examined, and all of them demonstrated the ability to form the carbon polymer polyhydroxyalkanoate (PHA) in the cell. The PHA in Dinoroseobacter sp. JL1447 was identified as poly-beta-hydroxybutyrate (PHB) according to evidence from Fourier transform infrared spectroscopy, differential scanning calorimetry, and (1)H nuclear magnetic resonance spectroscopy examinations. Carbon sources turned out to be critical for PHA production in AAPB. Among the eight media tested with Dinoroseobacter sp. JL1447, sodium acetate, giving a PHA production rate of 72%, was the most productive carbon source, followed by glucose, with a 68% PHA production rate. Such PHA production rates are among the highest recorded for all Bacteria. The C/N ratio of substrates was verified by the experiments as another key factor in PHA production. In the case of R. denitrificans OCh 114, PHA was not detected when the organism was cultured at C/N ratios of 3. Light is also important for the formation of PHA in AAPB. In the case of Dinoroseobacter sp. JL1447, up to a one-quarter increase in PHB production was observed when the culture underwent growth in a light-dark cycle compared to growth completely in the dark.
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influences of light and temperature on membrane potential and respiratory viability of an aerobic anoxygenic Phototrophic bacterium erythrobacter sp jl475
African Journal of Microbiology Research, 2010Co-Authors: Zaiqing Peng, Nianzhi JiaoAbstract:Flow cytometry’s (FCM) measurement of membrane potential (MP) and cell respiration viability based on continuous culture was used to investigate the responses of aerobic anoxygenic Phototrophic Bacteria (AAPB) in the heterotrophic growth and regulation mechanism of photosynthesis to environmental changes. An AAPB strain Erythrobacter sp. JL475 and a non-AAPB strain Erythrobacter sp. JL316 were used as the experimental Bacteria, both of which were isolated from the South China Sea. The results showed that light-cultured AAPB showed higher MP and biomass at 10°C, suggesting an obvious stimulation of light on AAPB growth. By contrast, dark-cultivated JL475 had higher MP and biomass at higher temperature (20, 30 and 40°C). The rate of heterotrophic respiration at different temperature environment ranked as follows: dark-cultivated JL316 > dark-cultivated JL475 > light/dark cycling cultivated JL475. Light undoubtedly increased the cell viability of AAPB, especially of apoptosis cells. The CTC+% at different carbon concentration ranked as follows: light/dark cycling cultivated JL475 > dark-cultivated JL316 > dark-cultivated JL475. It was concluded that the heterotrophic respiration would played a key role in energy metabolism of AAPB, photosynthesis may provide an advantage for AAPB to survive in a variety of diverse environments. Key words: Flow cytometry, aerobic anoxygenic Phototrophic Bacteria, membrane potential, respiration
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Roseophage RDJLΦ1, Infecting the Aerobic Anoxygenic Phototrophic Bacterium Roseobacter denitrificans OCh114
Applied and environmental microbiology, 2009Co-Authors: Yongyu Zhang, Nianzhi JiaoAbstract:A marine roseophage RDJL Phi1 lytically infecting Roseobacter denitrificans OCh114 was isolated and characterized. RDJL Phi1 can package several host cellular proteins into its virions, and its DNA is refractory to several commonly used restriction enzymes. This paper presents the first report of a bacteriophage isolated from the aerobic anoxygenic Phototrophic Bacteria.
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distinct distribution pattern of abundance and diversity of aerobic anoxygenic Phototrophic Bacteria in the global ocean
Environmental Microbiology, 2007Co-Authors: Nianzhi Jiao, Yonghui Zeng, Yao Zhang, Ning Hong, Rulong Liu, Feng Chen, Pinxian WangAbstract:Summary Aerobic anoxygenic Phototrophic Bacteria (AAPB) are an important Bacterial group with capability of harvesting light energy, and appear to have a particular role in the ocean’s carbon cycling. Yet the significance of AAPB relative to total Bacteria (AAPB%) in different marine regimes are still controversial, and variation trend of genetic diversity of AAPB along environmental gradients remains unclear. Here we present the first comprehensive observation of the global distribution of AAPB in the Pacific, Atlantic and Indian oceans, revealing a general pattern of high abundance of AAPB and AAPB% in coastal waters than oceanic waters. The Indian Ocean contained relatively high AAPB% compared with the other two oceans, corresponding to the high primary production in this region. Both abundance of AAPB and AAPB% were positively correlated with the concentration of chlorophyll a, while the diversity of AAPB decreased with increasing chlorophyll a values. Our results suggest that AAPB abundance and diversity follow opposite trends from oligotrophic to eutrophic regimes in the ocean.
Daniel Puyol - One of the best experts on this subject based on the ideXlab platform.
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alkalinity and not the oxidation state of the organic substrate is the key factor in domestic wastewater treatment by mixed cultures of purple Phototrophic Bacteria
Resources, 2020Co-Authors: Carol Nairn, Ivan Rodriguez, Yolanda Segura, Fernando J Martinez, R Molina, Juan A Melero, Natalia Gonzalezbenitez, M C Molina, Raquel Simarro, Daniel PuyolAbstract:Domestic wastewater treatment by purple Phototrophic Bacteria (PPB) is based on the assimilative uptake of organics and nutrients into the Bacterial biomass. Thereby, it strongly depends on the carbon/nutrients ratio of the wastewater. The physiological COD/N/P ratio for PPB growth in domestic wastewater makes the addition of an external organic carbon source necessary in order to allow for an efficient process. However, PPB need a source of alkalinity (as CO2) to grow on reduced organics that serves as an electron acceptor since biohydrogen production (an alternative electron sink) is inhibited by ammonium. A preliminary experiment showed that high nutrients-loading wastewater was limited by CO2 imbalance, leading to poor removal efficiencies. Subsequently, the effect of the oxidation state of the organics added as external organic carbon sources to PPB reactors treating low nutrients-loading domestic wastewater has been analyzed. Three organics were used as additives to PPB development in four consecutive batches: acetate (more oxidized), ethanol and butyrate (more reduced). The PPB population was settled and the general performance under the three situations, in terms of organics, N and P assimilation, and growth kinetics was not significantly different irrespective of the external organic carbon source. The reactors were dominated by PPB, though reduced organics allowed for dominance of Rhodopseudomonas palustris, whereas oxidized organics caused co-dominance of R. palustris and Rhodobacter capsulatus. Thereby, alkalinity (as bicarbonate), and not the oxidation state of the organics, is the key parameter for the efficient treatment of domestic wastewater by PPB.
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optimization of h2 production through minimization of co2 emissions by mixed cultures of purple Phototrophic Bacteria in aqueous samples
Water, 2020Co-Authors: Ioanna A Vasiliadou, Daniel Puyol, R Molina, Juan A Melero, Fernando J MartinezAbstract:One of the current challenges in the treatment of wastewater is the recovery and/or transformation of their resources into high value-added products, such as biohydrogen. The aim of the present study was to optimize the production of hydrogen by mixed cultures of purple Phototrophic Bacteria (PPB), targeting in low CO2 emission. Batch assays were conducted using different carbon (malic, butyric, acetic acid) and nitrogen (NH4Cl, Na-glutamate, N2 gas) sources by varying the chemical oxygen demand to nitrogen ratio (COD:N 100:3 to 100:44), under infrared radiation as sole energy source. Malate-glutamate (COD:N 100:5.5) and malate-NH4-N (COD:N 100:3) fed cultures, exhibited high H2 production rates of 2.3 and 2.5 mLH2/Lh, respectively. It was observed that the use of glutamate decreased the CO2 emission by 74% (13.4 mLCO2/L) as compared to NH4-N. The H2 production efficiency achieved by organic carbon substrates in combination with glutamate, was in the order of malic (370 mLH2/L) > butyric (145 mLH2/L) > acetic acid (95 mLH2/L). These substrates entailed partitioning of reducing power into biomass at 64%, 50% and 48%, respectively, whereas reductants were derived to biohydrogen at 5.8%, 6.1% and 2.1%, respectively. These results suggest that nitrogen source and carbon dioxide emissions play an important role in the optimization of hydrogen production by PPB.
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anaerobic digestion of purple Phototrophic Bacteria the release step of the partition release recover concept
Bioresource Technology, 2020Co-Authors: Tim Hulsen, Daniel Puyol, Ivan Rodriguez, Yolanda Segura, Fernando J Martinez, Damien John BatstoneAbstract:Purple Phototrophic Bacteria (PPB) have been proposed as a high-growth, assimilative option for wastewater treatment. The original partition-release-recover concept proposal requires their near complete digestion and release (and subsequent recovery) of energy and nutrients in an anaerobic digester. While the growth (partition) step has been extensively assessed, no work has been done on their anaerobic digestion characteristics (release). Continuous mesophilic (20d) and thermophilic (10d) digestion could achieve around 55% volatile solids degradation (VSD), with 35% (mesophilic) and 20% (thermophilic) nitrogen solubilisation. Post digestion (with/without pretreatment) could increase the VSD to 70% and nitrogen solubilisation to 43%. A number of pretreatment options were tested, with high temperature and sonication being relatively effective, and chemical treatment, and temperature phased digestion being relatively ineffective vs controls. Overall, anaerobic digestion of PPB results in substantial residual particulate material, with an increased nitrogen content, and avenues to effectively utilise this residue should be identified.
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purple Phototrophic Bacteria as a platform to create the next generation of wastewater treatment plants energy and resource recovery
2020Co-Authors: Daniel Puyol, Tim Hulsen, Fernando J Martinez, Juan A Melero, V M Monsalvo, E Marin, F Rogalla, Damien John BatstoneAbstract:New trends in wastewater treatment are addressing energy and resource recovery in holistic platforms. These include upstream and downstream procedures, and try to address energy neutrality, or at least economic profitability. Purple Phototrophic Bacteria (PPB) are emerging as a core for photo-assisted biological processes for these purposes. The high metabolic versatility and potential applications of these fascinating microorganisms have turned them into one of the most promising alternatives in wastewater biorefinery platforms. This chapter analyzes the main factors causing the growth of PPB technologies in environmental technology research groups all over the world. The metabolism of these Bacteria is overviewed, including modeling. Finally, the chapter reviews the main achievements in both domestic as well as industrial wastewater treatment with these microorganisms, especially focused on resource recovery and scaling up.
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biological and bioelectrochemical systems for hydrogen production and carbon fixation using purple Phototrophic Bacteria
Frontiers in Energy Research, 2018Co-Authors: Ioanna A Vasiliadou, Fernando J Martinez, Juan A Melero, Antonio Berna, Carlos Manchon, Abraham Estevenunez, Daniel PuyolAbstract:Domestic and industrial wastewaters contain organic substrates and nutrients that can be recovered instead of being dissipated by emerging efficient technologies. The aim of this study was to promote bio-hydrogen production and carbon fixation using a mixed culture of purple Phototrophic Bacteria (PPB) that use infrared radiation in presence or absence of an electrode as electron donor. In order to evaluate the hydrogen production under electrode-free conditions, batch experiments were conducted using different nitrogen (NH4Cl, Na-glutamate, N2 gas) and carbon sources (malic-, butyric-, acetic- acids) under various COD:N ratios. Results suggested that the efficiency of PPB to produce biogenic H2 was highly dependent on the substrates used. The maximum hydrogen production (H2_max, 423 mLH2/L) and production rate (H2_rate, 2.71 mLH2/Lh) were achieved using malic acid and Na-glutamate at a COD:N ratio of 100:15. Under these optimum conditions, a significant fixation of nitrogen in form of single-cell proteins (874.4 mg/L) was also detected. Under bio-electrochemical conditions using a H-cell bio-electrochemical device, the PPB were grown planktonic in the bio-cathode chamber with the optimum substrate ratio of malic acid and Na-glutamate. A redox potential of -0.5 V (vs Ag/AgCl) under bio-electrochemical conditions produced comparable amounts of bio-hydrogen but significantly negligible traces of CO2 as compared to the biological system (11.8 mLCO2/L). This suggests that PPB can interact with the cathode to extract electrons for further CO2 re-fixation (coming from the TCA cycle) into the Calvin cycle, thereby improving the C usage. It has also been observed during cyclic voltammograms that a redox potential of -0.8 V favours considerably the electrons consumption by the PPB culture, suggesting that the PPB can use these electrons to increase the biohydrogen production. These results are expected to prove the feasibility of stimulating PPB through bio-electrochemical processes in the production of H2 from wastewater resources, which is a field of special novelty and still unexplored.