A batch study on the bio-fixation of carbon dioxide in the absorbed solution from a chemical wet scrubber by hot spring and marine algae

Biofixation of carbon dioxide by Spirulina sp. and Scenedesmus obliquus cultivated in a three-stage serial tubular photobioreactor

Bioelectrochemical processes and cellulosic carbon source enhance the autotrophic and heterotrophic denitrification of low C/N ratio wastewater in tidal flow constructed wetland - Microbial fuel cells

Serratia plymuthica UBCF_13 is one of the biocontrol bacteria that can suppress the growth of phytopathogenic fungi. Bacterial antifungal activity is influenced by several environmental factors, including the addition of carbon and nitrogen sources. This study aimed to determine the carbon and nitrogen sources that can encourage the maximum antagonistic activity of the extracellular compound from S. plymuthica UBCF_13. Carbon and nitrogen sources used in this study were glucose, sucrose, glycerol, ethanol, peptone, ammonium sulfate, tryptone, and yeast extract, with a concentration of 2 %. Bacterial extracellular compounds were applied to phytopathogenic fungi [Colletotrichum gloeosporioides, Sclerotium rolfsii, and Fusarium oxysporum] to see their antifungal activity. Data were statistically analyzed using one-way variance with DNMRT at the 5 % level. The best antifungal activity against C. gloeosporioides resulted from the addition of carbon source [ethanol] 22.28 % and nitrogen source [peptone] 16.94 %. The best antifungal activity against S. rolfsii fungi resulted from the addition of carbon source [ethanol] 14.67 % and nitrogen source [ammonium sulfate] 15.53 %. The inhibition ability of the extracellular bacterial compounds of S. plymuthica UBCF_13 in recording the growth of S. rolfsii with the addition of carbon and nitrogen is fairly low. S. plymuthica bacteria are less able to produce antifungal compounds that can suppress the growth of S. rolfsii fungi. The best antifungal activity against F. oxysporum fungi resulted from the addition of carbon source [ethanol] 8.47 % and nitrogen source [ammonium sulfate and tryptone] 28.25 % & 26.88 %.

Chapter 19 - Microalgae culture technology for carbon dioxide biomitigation

SummaryPhotosynthetic bacteria are abundant in alkaline, terrestrial hot springs and there is a long history of research on phototrophs in Yellowstone National Park (YNP). Hot springs provide a framework to examine the ecophysiology of phototrophs in situ because they provide natural gradients of geochemistry, pH and temperature. Phototrophs within the Cyanobacteria and Chloroflexi groups are frequently observed in alkaline hot springs. Decades of research has determined that temperature constrains Cyanobacteria in alkaline hot springs, but factors that constrain the distribution of phototrophic Chloroflexi remain unresolved. Using a combination of 16S rRNA gene sequencing and photoassimilation microcosms, we tested the hypothesis that temperature would constrain the activity and composition of phototrophic Cyanobacteria and Chloroflexi. We expected diversity and rates of photoassimilation to decrease with increasing temperature. We report 16S rRNA amplicon sequencing along with carbon isotope signatures and photoassimilation from 45 to 72°C in two alkaline hot springs. We find that Roseiflexus, Chloroflexus (Chloroflexi) and Leptococcus (Cyanobacteria) operational taxonomic units (OTUs) have distinct distributions with temperature. This distribution suggests that, like phototrophic Cyanobacteria, temperature selects for specific phototrophic Chloroflexi taxa. The richness of phototrophic Cyanobacteria decreased with increasing temperature along with a decrease in oxygenic photosynthesis, whereas Chloroflexi richness and rates of anoxygenic photosynthesis did not decrease with increasing temperature, even at temperatures approaching the upper limit of photosynthesis (~72–73°C). Our carbon isotopic data suggest an increasing prevalence of the 3‐hydroxypropionate pathway with decreasing temperature coincident with photoautotrophic Chloroflexi. Together these results indicate temperature plays a role in defining the niche space of phototrophic Chloroflexi (as has been observed for Cyanobacteria), but other factors such as morphology, geochemistry, or metabolic diversity of Chloroflexi, in addition to temperature, could determine the niche space of this highly versatile group.

Streamer biofilm communities (SBC) are often observed within chemosynthetic zones of Yellowstone hot spring outflow channels, where temperatures exceed those conducive to photosynthesis. Nearest the hydrothermal source (75–88°C) SBC comprise thermophilic Archaea and Bacteria, often mixed communities including Desulfurococcales and uncultured Crenarchaeota, as well as Aquificae and Thermus, each carrying diagnostic membrane lipid biomarkers. We tested the hypothesis that SBC can alternate their metabolism between autotrophy and heterotrophy depending on substrate availability. Feeding experiments were performed at two alkaline hot springs in Yellowstone National Park: Octopus Spring and “Bison Pool,” using various 13C-labeled substrates (bicarbonate, formate, acetate, and glucose) to determine the relative uptake of these different carbon sources. Highest 13C uptake, at both sites, was from acetate into almost all bacterial fatty acids, particularly into methyl-branched C15, C17 and C19 fatty acids that are diagnostic for Thermus/Meiothermus, and some Firmicutes as well as into universally common C16:0 and C18:0 fatty acids. 13C-glucose showed a similar, but a 10–30 times lower uptake across most fatty acids. 13C-bicarbonate uptake, signifying the presence of autotrophic communities was only significant at “Bison Pool” and was observed predominantly in non-specific saturated C16, C18, C20, and C22 fatty acids. Incorporation of 13C-formate occurred only at very low rates at “Bison Pool” and was almost undetectable at Octopus Spring, suggesting that formate is not an important carbon source for SBC. 13C-uptake into archaeal lipids occurred predominantly with 13C-acetate, suggesting also that archaeal communities at both springs have primarily heterotrophic carbon assimilation pathways. We hypothesize that these communities are energy-limited and predominantly nurtured by input of exogenous organic material, with only a small fraction being sustained by autotrophic growth.

Alkaline hot springs are unique extreme habitats resemble the early Earth and present a valuable resource for the discovery of procaryotic community diversity and isolation of the novel thermophilic Bacteria and Archaea. One of the model for the possible origin of biochemistry in alkaline hot springs revealed the acetyl-CoA pathway of CO2 fixation might be the most ancient form of carbon metabolism. Recent phylogenetic studies have suggested that the phylum Acetothermia is one of the deep branches of the Bacteria domain. Firstly Acetothermia (Candidate division OP1) was characterized in a culture independent molecular phylogenetic survey based on the 16S rRNA gene of the sulfide-rich hot spring, Obsidian Pool, a 75 to 95oC hot spring. Two nearly complete genomes of Acetothermia were established based on genome-resolved metagenomic analysis and its capability of implementing acetogenesis through the ancient reductive acetyl-CoA pathway by utilizing CO2 and H2 was revealed. Although genomic, proteomic and metagenomic approaches investigate basic metabolism and potentional energy conservation of uncultivated candidate phyla but ecological roles of these bacteria and general patterns of diversity and community structure stay unclear. General hydrochemical and geological characterization of alkaline thermal springs of the Baikal Rift zone with high silica concentrations and a nitrogen dominated gas phase is provided. Previous microbiogical studies based on culture-dependent methods recovered a large number of bacterial strains from thermal springs located in Baikal Rift zone. We combined microbial communities analysis by using high-throughput 16S rRNA gene sequencing, biogeochemical measurements, sediment mineralogy and physicochemical characteristics to investigate ecosystems of alkaline hot springs located in the Baikal Rift zone. Uncultivated bacteria belonging to the phylum Acetothermia, along with members of the phyla Firmicutes and Proteobacteria, were identified as the dominant group in hydrothermal sediments communities in the alkaline hot springs of Baikal Rift zone. In bottom sediments of the Alla hot spring, about 57% of all classified sequences represent this phylum. Geochemistry of fluids and sample type were strongly correlated with microbial community composition. The Acetothermia exhibited the highest relative abundance in sediment microbial community associated with alkaline thermal fluids enriched in Fe, Zn, Ni, Al and Cr.

The mass transfer of carbon dioxide through the outer polyethylene casing of district heating pipes, at room temperature, was evaluated, using different test methods. The mass transfer either through polyethylene casings on polyurethane preinsulated district heating pipes or through polyethylene casings alone was mea sured. Permeability coefficients of different polyethylene casings were about 20 · 10-18 kg·m-1·s-1·Pa-1. Permeability coefficients for carbon dioxide in polyurethane foam is about 100 times lower, which means that the mass transfer resistance to car bon dioxide of the polyurethane foam in a district heating pipe is negligible in com parison with the polyethylene casing.

Storing livestock manure is the primary stage of manure management where microbial processes and chemical reactions result in the release of methane (CH), nitrous oxide (NO), ammonia (NH), and carbon dioxide (CO). This study examined the reduction of CH emissions from slurry storage under two temperatures (cool [10°C] and warm [30°C]) when a glucose-rich substrate (brewing sugar) and activated effective microorganisms were applied at 10% (w/w) and 5% (v/w), respectively. Brewing sugar addition influenced microbial anaerobic respiration, resulting in a reduction of slurry pH to <5.0, through "self-acidification" caused by lactic acid production. Subsequently, CH emissions were significantly reduced by 87 and 99% in the cool and warm environments, respectively. The effective microorganism treatment did not change the chemical characteristics of the slurry but reduced CH emissions by 17 and 27% ( < 0.05) in the cool and warm environments, respectively. These results suggest that self-acidification after addition of a carbon source may be a promising alternative to slurry acidification using concentrated acids.

The Heart Lake Geyser Basin (HLGB) is remotely located at the base of Mount Sheridan in southern Yellowstone National Park (YNP), Wyoming, USA and is situated along Witch Creek and the northwestern shore of Heart Lake. Likely because of its location, little is known about the microbial community structure of springs in the HLGB. Bacterial and archaeal populations were monitored via small subunit (SSU) rRNA gene pyrosequencing over 3 years in 3 alkaline (pH 8.5) hot springs with varying temperatures (44°C, 63°C, 75°C). The bacterial populations were generally stable over time, but varied by temperature. The dominant bacterial community changed from moderately thermophilic and photosynthetic members (Cyanobacteria and Chloroflexi) at 44°C to a mixed photosynthetic and thermophilic community (Deinococcus-Thermus) at 63°C and a non-photosynthetic thermophilic community at 75°C. The archaeal community was more variable across time and was predominantly a methanogenic community in the 44 and 63°C springs and a thermophilic community in the 75°C spring. The 75°C spring demonstrated large shifts in the archaeal populations and was predominantly Candidatus Nitrosocaldus, an ammonia-oxidizing crenarchaeote, in the 2007 sample, and almost exclusively Thermofilum or Candidatus Caldiarchaeum in the 2009 sample, depending on SSU rRNA gene region examined. The majority of sequences were dissimilar (≥10% different) to any known organisms suggesting that HLGB possesses numerous new phylogenetic groups that warrant cultivation efforts.

Yellowstone National Park is well known among microbiologists for its unique microbial ecology, where microorganisms adapt to extreme environments (temperature and pH) associated with geothermal features including hot springs, geysers, and fumaroles. Recently, we developed a portable, battery-operated potentiostat to control the potential of electrodes in in Heart Lake Geyser Basin. The goal of this work is to compare the electrochemical activity in polarized and non-polarized electrodes deployed in alkaline hot springs. We used carbon fabric electrodes (3 inch x 3 inch) working electrode, graphite felt (5 inch x 5 inch x 0.25 inch) counter electrode, and Ag/AgCl reference electrode. A carbon fabric electrode (3 inch x 3 inch) was used as a non-polarized control. These electrodes were immersed in four hot springs with temperature ranging between 45οC and 91οC, and pH between 8 and 8.8. In total, eight polarized electrodes and controls were deployed; one anode and one cathode in each hot spring. The cathodes were deployed approximately 1 foot below the surface of the water, and polarized at -0.6 VAg/AgCl. The anodes were deployed near the bottom of each hot spring at depth 3-10 feet, and polarized at +0.4 VAg/AgCl. All electrodes were deployed for a period of 30 days, and then harvested for electrochemical analysis. Cyclic voltammetry reveals the presence of multiple anodic and cathodic peaks in both polarized and control electrodes. Increased temperature seems to activate redox couples, with anodic (positive current) peaks at -0.2 and 0.35 VAg/AgCl, and two corresponding cathodic (negative current) peaks at -0.4 and 0.25 VAg/AgCl. Temperature-controlled experiments shows that the peak height increases with temperature, which alludes to the presence of thermally-activated electrochemical reactions.

It was the objective of the present study to increase the production of glucoamylase by Aspergillus awamori through solid state fermentation, using wheat bran as the main carbon source and (NH4)2SO4, urea, KH2PO4, glucose, maltose and starch as additional nitrogen, phosphorus, and carbon sources. The production of glucoamylase is strongly influenced by N and C sources. A 100% increase was observed when the (NH4)2SO4 was replaced by urea, with C/N = 4.8, using maltose as the additional carbon source. C/P ratios in a range of 5.1 to 28.7 did not induce glucoamylase production under the studied conditions.

Efficient denitrification of liquid digestate with its indigenous microflora

Torulaspora delbrueckii metabolism was assessed in a synthetic culture medium similar to grape must under various conditions: no aeration and three different oxygen feeds, in order to determine the effect of oxygen on metabolism. Carbon and nitrogen mass balances were calculated to quantify metabolic fluxes. The effect of oxygen was to decrease the flux of carbon going into the fermentation pathway in favor of growth. In the absence of aeration, higher amounts of glycerol were produced, probably to maintain the redox balance. The oxygen requirement of this strain was high, since even for the highest air supply oxygen became limiting after 24 h. Nevertheless, this strain developed well in the absence of oxygen and consumed 220 g/L of sugars (glucose/fructose) in 166 h at 20 °C, giving a good ethanol yield (0.50 g/g).

Migration and controlling factors of rare earth elements in geothermal systems on the southern Tibetan Plateau