Cyanobacterium Aponinum Research Articles

Isolation, Characterization, Moisturization and Anti-HepG2 Cell Activities of a Novel Polysaccharide from Cyanobacterium aponinum.

Polysaccharides from cyanobacteria are extensively reported for their complex structures, good biocompatibility, and diverse bioactivities, but only a few cyanobacterial species have been exploited for the biotechnological production of polysaccharides. According to our previous study, the newly isolated marine cyanobacterium Cyanobacterium aponinum SCSIO-45682 was a good candidate for polysaccharide production. This work provided a systematic study of the extraction optimization, isolation, structural characterization, and bioactivity evaluation of polysaccharides from C. aponinum SCSIO-45682. Results showed that the crude polysaccharide yield of C. aponinum reached 17.02% by hot water extraction. The crude polysaccharides showed a porous and fibrous structure, as well as good moisture absorption and retention capacities comparable to that of sodium alginate. A homogeneous polysaccharide (Cyanobacterium aponinum polysaccharide, CAP) was obtained after cellulose DEAE-52 column and Sephadex G-100 column purification. CAP possessed a high molecular weight of 4596.64 kDa. It was mainly composed of fucose, galactose, and galacturonic acid, with a molar ratio of 15.27:11.39:8.64. The uronic acid content and sulfate content of CAP was 12.96% and 18.06%, respectively. Furthermore, CAP showed an in vitro growth inhibition effect on human hepatocellular carcinoma (HepG2) cells. The above results indicated the potential of polysaccharides from the marine cyanobacterium C. aponinum SCSIO-45682 as a moisturizer and anticancer addictive applied in cosmetical and pharmaceutical industries.

Direct air capture using halophilic Cyanobacterium aponinum PCC10605 under illumination of light-emitting diodes in marine environment

Excessive carbon dioxide (CO2) emissions have become a disaster, calling for an effective way to reduce atmospheric CO2 content. Cyanobacteria, also known as blue-green algae, are potent natural carbon sinks with efficient photosynthesis and produce valuable compounds. Herein, we demonstrated the excellent properties of Cyanobacterium aponinum PCC10605 (Capo) in maintaining growth and protein accumulation under salt stress and red light-emitting diodes (LEDs) illumination at 660 nm under direct air capture (DAC) condition. Multi-factor optimization from response surface methodology revealed the best condition of 25 °C, 70 μE light intensity, 17 g/L salt, 16 to 8 h for light to dark period, and 6 mM nitrogen to yield the highest combination of 1.49 g/L biomass and 19.1 % C-phycocyanin (C-PC) content. Capo also thrived in 50 % seawater from Penghu, Taiwan where its DAC capacity was confirmed using an elemental analyzer, showing that 48.2 % carbon content was equivalent to specific capture ratio of 1.75 g-CO2/g-DCW and volumetric efficiency of 2.62 g-CO2/L, respectively. Finally, scaling up cultivation in 2-liter photobioreactor was successfully carried out under red LED illumination. The potential of Capo in reducing atmospheric CO2 level represents an advancement in sustainable biotechnology for climate change mitigation.

Deciphering Evolutionary Trajectories of Lactate Dehydrogenases Provides New Insights into Allostery.

Lactate dehydrogenase (LDH, EC.1.1.127) is an important enzyme engaged in the anaerobic metabolism of cells, catalyzing the conversion of pyruvate to lactate and NADH to NAD+. LDH is a relevant enzyme to investigate structure-function relationships. The present work provides the missing link in our understanding of the evolution of LDHs. This allows to explain (i) the various evolutionary origins of LDHs in eukaryotic cells and their further diversification and (ii) subtle phenotypic modifications with respect to their regulation capacity. We identified a group of cyanobacterial LDHs displaying eukaryotic-like LDH sequence features. The biochemical and structural characterization of Cyanobacterium aponinum LDH, taken as representative, unexpectedly revealed that it displays homotropic and heterotropic activation, typical of an allosteric enzyme, whereas it harbors a long N-terminal extension, a structural feature considered responsible for the lack of allosteric capacity in eukaryotic LDHs. Its crystallographic structure was solved in 2 different configurations typical of the R-active and T-inactive states encountered in allosteric LDHs. Structural comparisons coupled with our evolutionary analyses helped to identify 2 amino acid positions that could have had a major role in the attenuation and extinction of the allosteric activation in eukaryotic LDHs rather than the presence of the N-terminal extension. We tested this hypothesis by site-directed mutagenesis. The resulting C. aponinum LDH mutants displayed reduced allosteric capacity mimicking those encountered in plants and human LDHs. This study provides a new evolutionary scenario of LDHs that unifies descriptions of regulatory properties with structural and mutational patterns of these important enzymes.

Identification of Extracellular Signal of Secretory Peptides in Cyanobacterium aponinum PCC10605 by In Silico Approach

Identification of Extracellular Signal of Secretory Peptides in Cyanobacterium aponinum PCC10605 by In Silico Approach

Copper(II) bioremoval by thermophile Cyanobacterium aponinum

In the current study, bioremediation of Cu(II) by thermophile Cyanobacterium aponinum has been studied in BG11 media under different conditions. The optimum pH was 9 due to the maximum Cu(II) bioremoval efficiency as 71% in the medium with12.8 mg/L Cu(II). According to the results obtained from the trials, the highest bioremoval was 76.6% in the medium including 9.7 mg/L Cu(II) for incubation period of 10 days. When the effect of increasing temperature (25-45 °C) and biomass [20% and 40% (v/v)] concentrations on bioremediation by C. aponinum was investigated, the highest heavy metal removal was found 75.8% at 45 °C, 12.8 mg/L Cu(II), and 20% (v/v) biomass concentration. It was 76.3% in the medium with 13.8 mg/L pollutant, 40% (v/v) biomass concentration. The qm (maximum specific Cu(II) removal) was found as 6.1 mg/g at 45 °C in BG11 with 40% (v/v) biomass and 13.8 mg/L Cu(II). It has been concluded that Cu(II) bioremediation by thermophile C. aponinum was firstly investigated at various environmental conditions in this study. The results indicated that the tested cyanobacterium had a great potential to remove heavy metals from the aquatic environments, containing Cu(II).

Thermal cultivation of halophilic Cyanobacterium aponinum for C-phycocyanin production and simultaneously reducing carbon emission using wastewater

A newly halophilic Cyanobacteria aponinum PCC10605 is first explored as a robust blue alga compared to Chlorella sorokiniana (CS), Chlorella vulgaris (CV) and Chlamydomonas reinhardtii (CC400) that can be cultured at high salinity and mesophilic condition. The Logistic and Gompertz models were applied to evaluate cell growth of four algal strains under mixotrophic and autotrophic cultivation, thus the optimal condition for PCC10605 was indicated in autotrophic and 20 g/L seawater at 39°C. When nitrogen and phosphorus concentration was at the ratio of 3:1, PCC10605 grew fast and had the better C-phycocyanin (C-PC) productivity, achieving to 1.53 g/L of biomass and 0.492 g/L of C-PC under 25% light intensity and 12:12 light period. Finally, a feasible and negative carbon emission via PCC10605 which cultured in the mixed medium and wastewater at 1:2 vol ratio (i.e., M1W2), reaching to 1.227 g/L of biomass concentration, 0.503 g/L C-PC production, reducing 40.5% of chemical oxygen demand (COD), and capturing 1.71 g-CO2 simultaneously in a Photo System Instruments (PSI).

The effects of fresh mango consumption on gut health and microbiome - Randomized controlled trial.

Some individual fruits have been widely researched for their effects on overall health and correlations with chronic diseases. The beneficial effects of mango supplementation on metabolic diseases have been detected. However, research into mango consumption on gut health, including the microbiome, is limited to processed mango preparations or peels. Our goal was to examine the effects of fresh mango consumption on the gut microbiome, gut permeability proteins, and bowel movement habits in overweight/obese individuals. In a 12-week crossover design study, 27 participants consumed 100 kcal/day of either mangos or low-fat cookies with a washout period of 4 weeks. The mango intervention showed higher Shannon-Wiener and Simpson alpha diversity indices of the microbiome than the low-fat cookie intervention in week 4. Significant differences in beta diversity of the microbiome were found between diet interventions at week 12. Mango consumption increased the abundance of Prevotella maculosa, Corynebacterium pyruviciproducens, and Mogibacterium timidum while it decreased Prevotella copri. Low-fat cookie intake increased Cyanobacterium aponinum and Desulfovibrio butyratiphilus and reduced Alloscardovia omnicolens. There were no significant differences in circulating gut permeability protein (ZO-1, claudin-2, and occludin) levels. There was a slight increase in the amount of bowel movement with mango consumption, but no significant findings for frequency, consistency, strain, pain, and constipation in bowel movement between trials. Given these results, it can be concluded that consumption of mango may have positive effects on the gut health, which may yield possible health benefits for chronic disease that deserve further study.

Putative biosynthesis mechanism of the neurotoxin β-N-methylamino-L-alanine in marine diatoms based on a transcriptomics approach.

The neurotoxin β-N-methylamino-L-alanine (BMAA) has been presumed as an environmental cause of human neurodegenerative disorders, such as Alzheimer's disease. Marine diatoms Thalassiosira minima are demonstrated here to produce BMAA-containing proteins in axenic culture while the isomer diaminobutyric acid was bacterially produced. In the co-culture with Cyanobacterium aponinum, diatom growth was inhibited but the biosynthesis of BMAA-containing proteins was stimulated up to seven times higher than that of the control group by cell-cell interactions. The stimulation effect was not caused by the cyanobacterial filtrate. Nitrogen deprivation also doubled the BMAA content of T. minima cells. Transcriptome analysis of the diatom in mixed culture revealed that pathways involved in T. minima metabolism and cellular functions were mainly influenced, including KEGG pathways valine and leucine/isoleucine degradation, endocytosis, pantothenate and CoA biosynthesis, and SNARE interactions in vesicular transport. Based on the expression changes of genes related to protein biosynthesis, it was hypothesized that ubiquitination and autophagy suppression, and limited COPII vesicles transport accuracy and efficiency were responsible for biosynthesis of BMAA-containing proteins in T. minima. This study represents a first application of transcriptomics to investigate the biological processes associated with BMAA biosynthesis in diatoms.

Isolation and Identification of Tersakan Stream (Amasya, Suluova TÜRKİYE) Cyanobacteria and Investigation of the Presence of the Microcystin-LR

Cyanobacteria are a concern worldwide due to their blooms and the toxins they produce. The aim of this study is to reveal the cyanobacterial diversity of Tersakan Stream and toxin analysis. For these purpose, water samples were taken from Tersakan Stream in 2018 and cyanobacterial diversity was determined by culture-dependent and independent methods. PCR amplification of microcystin genes (McyB and McyE) and Microcystin-LR (L:Leucine, R: Arginine) (MC-LR) analysis in water sample was performed. While 10 different Cyanobacteria were identified by light microscopy examination and 16S rRNA + ITS sequence, less diversity was revealed by culture-independent methods. Sequences of the isolates were associated with Pseudanabaena lonchoides, Leptolyngbya sp, Toxifilum sp, Cylindrospermum moravicum, Nostoc sp, Oscillatoria sp, Synechocystis sp, Synechococcus sp, Cyanobacterium aponinum and Cyanobium sp. Culture-independent sequences were associated with Microcytis sp, Nostoc sp, Cyanobium sp, Dolichospermum sp, Anabaena sp, Leptolyngbya sp and Uncultured cyanobacterium. Microcystin analysis was performed by both molecular and analytical methods. PCR results of McyB and McyE genes supported the HPLC-DAD analysis result. 0.467 μg L-1 microcystin LR was detected in Tersakan Stream by HPLC-DAD analysis. Although the microcystin concentration is low, Tersakan Stream is an important area to be monitored with its eutrophic character and cyanobacterial diversity.

Effects of Mango Fruit Consumption on the Diversity of the Gut Microbiome

ObjectivesSome individual fruits have been widely researched for their effects on overall health and correlations with chronic diseases, highlighting the benefits and importance of incorporation of fruit in the diet. Beneficial effects of mango supplementation on metabolic diseases have been detected, however, research of mango consumption on the gut microbiome is sparse. Therefore, this study examined the effect of fresh mango consumption on the diversity of the gut microbiome.MethodsIn a 12-week crossover design study, 27 participants (16 males and 11 females, age 26.0 ± 8.1 years, BMI 31.8 ± 4.1 kg/m2) consumed 100 kcal/day of either mangos or low fat cookies with a washout period of 4 weeks. Fecal samples were analyzed for gut microbiome analysis. Alpha diversity, beta diversity, and relative abundance analyses were conducted using R and the RStudio.ResultsThe mango intervention resulted in higher Shannon-Wiener and Simpson alpha diversity indices of the microbiome than the cookie intervention in week 4. Significant differences in beta diversity of the microbiome were found between diet interventions at week 12. Mango consumption also increased the abundance of Prevotella maculosa, Corynebacterium pyruviciproducens, and Mogibacterium timidum while decreased Prevotella copri. Cookie intake increased Cyanobacterium aponinum and Desulfovibrio butyratiphilus and reduced Alloscardovia omnicolens.ConclusionsGiven these results, it can be concluded that consumption of mango may have positive effects on the gut microflora, which in turn may yield possible health benefits for chronic diseases that deserve further study.Funding SourcesThe National Mango Board [#6,030,204].

Secretomics: a biochemical footprinting tool for developing microalgal cultivation strategies.

Microalgae offer a promising source of biofuel and a wide array of high-value biomolecules. Large-scale cultivation of microalgae at low density poses a significant challenge in terms of water management. High-density microalgae cultivation, however, can be challenging due to biochemical changes associated with growth dynamics. Therefore, there is a need for a biomarker that can predict the optimum density for high biomass cultivation. A locally isolated microalga Cyanobacterium aponinum CCC734 was grown with optimized nitrogen and phosphorus in the ratio of 12:1 for sustained high biomass productivity. To understand density-associated bottlenecks secretome dynamics were monitored at biomass densities from 0.6 ± 0.1 to 7 ± 0.1g/L (2 to 22 OD) in batch mode. Liquid chromatography coupled with mass spectrometry identified 880 exometabolites in the supernatant of C. aponinum CCC734. The PCA analysis showed similarity between exometabolite profiles at low (4 and 8 OD) and mid (12 and 16 OD), whereas distinctly separate at high biomass concentrations (20 and 22 OD). Ten exometabolites were selected based on their role in influencing growth and are specifically present at low, mid, and high biomass concentrations. Taking cues from secretome dynamics, 5.0 ± 0.5g/L biomass concentration (16 OD) was optimal for C. aponinum CCC734 cultivation. Further validation was performed with a semi-turbidostat mode of cultivation for 29days with a volumetric productivity of 1.0 ± 0.2g/L/day. The secretomes-based footprinting tool is the first comprehensive growth study of exometabolite at the molecular level at variable biomass densities. This tool may be utilized in analyzing and directing microalgal cultivation strategies and reduction in overall operating costs.

Production, isolation and characterization of C-phycocyanin from a new halo-tolerant Cyanobacterium aponinum using seawater

A halo-tolerant Cyanobacterium aponinum PCC 10605 was applied for the first time to produce high-level C-phycocyanin (C-PC). Combined with chemical extraction with sodium phosphate buffer and physical treatment using high pressure homogenization, a higher titer of C-PC was achieved. The culture conditions were optimized by mixing nitrate and ammonia ions, 2% carbon dioxide, and conditional light intensity. Thus, strain PCC10605 produced the highest titer C-PC of 0.652 g/g-DCW in the N1A2 medium with 10% light intensity and 16:8 light-period on day 7. PCC10605 accumulated 0.51 g-CPC/g-DCW at 20 g/L NaCl, while it grew normally in seawater with 30 g/L salinity, thus confirmed that PCC10605 was halo-tolerant strain. Besides, PCC10605 survived in 0.12 g/L phosphate medium that has never been reported. Finally, the purified C-PC exhibited DPPH, superoxide scavenging activity and antibacterial activity, which displayed 87.6%, and 18.7% removal of free radical, and 1.98 cm of inhibition zone for Escherichia coli.

The structure of photosystem I from a high-light-tolerant cyanobacteria.

Photosynthetic organisms have adapted to survive a myriad of extreme environments from the earth's deserts to its poles, yet the proteins that carry out the light reactions of photosynthesis are highly conserved from the cyanobacteria to modern day crops. To investigate adaptations of the photosynthetic machinery in cyanobacteria to excessive light stress, we isolated a new strain of cyanobacteria, Cyanobacterium aponinum 0216, from the extreme light environment of the Sonoran Desert. Here we report the biochemical characterization and the 2.7 Å resolution structure of trimeric photosystem I from this high-light-tolerant cyanobacterium. The structure shows a new conformation of the PsaL C-terminus that supports trimer formation of cyanobacterial photosystem I. The spectroscopic analysis of this photosystem I revealed a decrease in far-red absorption, which is attributed to a decrease in the number of long- wavelength chlorophylls. Using these findings, we constructed two chimeric PSIs in Synechocystis sp. PCC 6803 demonstrating how unique structural features in photosynthetic complexes can change spectroscopic properties, allowing organisms to thrive under different environmental stresses.

Microalgal Cultivation in Secondary Effluents: Enhancement of Algal Biomass, Nutrient Removal, and Lipid Productivity

The growth performance, nutrient removal, lipid accumulation and morphological changes of Cyanobacterium aponinum OUC1 and Scenedesmus obliquus which were cultured in secondary effluents from two wastewater treatment plants: Tuandao Wastewater Treatment Plant (ETD) and Licun River Wastewater Treatment Plant (ELR) were investigated. The results showed that both C. aponinum OUC1 and S. obliquus have superior growth performances in both undiluted effluents, while the better of them was that in ETD effluent, with cell densities of C. aponinum OUC1 and S. obliquus increased by 159% and 66% over that of BG11 (control), respectively. Regarding nutrient removal, S. obliquus could completely remove inorganic phosphorus, and decrease ammonia nitrogen in ETD effluent by 81%. In addition, both C. aponinum OUC1 and S. obliquus cultivated in ETD exhibited extraordinary potential for biofuel production, increasing lipid productivities by 133% and 89% of that cultivated in ELR, respectively. As to ultrastructural changes, the differences in the lipoidal globules and glycogen granules of S. obliquus and C. aponinum OUC1 among the ETD and ELR treatments were mostly related to phosphorus limitations. The findings from this research reveal the probability using the secondary effluents as cultivation media to enhance algal biomass, nutrient removal and lipid productivity.

Prospects for the creation of a waste-free technology for wastewater treatment and utilization of carbon dioxide based on cyanobacteria for biodiesel production

Current fresh water and energy shortage determines the need to study the possibilities of using living objects in bioenergy and environmental purification technologies. The development of waste-free technologies allows waste recycling, which saves raw materials and energy, in turn, reducing waste generation. The effect of different carbon dioxide concentrations and wastewater from households on the growth of cyanobacteria was studied in order to determine their capabilities in the purification processes. It was found that the optimal CO2 concentration for the cultivation of cyanobacteria Cyanobacterium sp. IPPAS B-1200 and Desertifilum sp. IPPAS B-1220 was 10 %, and for the Cyanobacterium aponinum IPPAS B-1201 – 5%. It was revealed that the cultivation of the cyanobacterium Cyanobacterium sp. IPPASB-1200 on wastewater from the water storage reduces the concentration of organic pollutants and, accordingly, improves the physicochemical properties of water. The cleaning percentage for selected pollutants was 68–100 %. It was shown that the most optimal ratio of wastewater to nutrient media for cyanobacteria cultivation were 25:75 and 50:50. The lipid content (%/dry weight) in the biomass of the studied strains of cyanobacteria ranges from 15 to 22% after cultivation in wastewater. It was determined that the strains of Cyanobacterium genus were the most suitable for the production of biodiesel according to their fatty acids composition. It was determined that lipids were composed of only saturated and monounsaturated fatty acids. As a result of the studies, the optimal conditions for the growth of Cyanobacterium sp. IPPAS B-1200 were determined. This microorganism has a good potential to produce biodiesel as a producer of saturated and monounsaturated middle-chain-length fatty acids.

Phylogenetic analysis of isolated Phormidium sp. and Cyanobacterium aponinum from Kor River

Cyanobacteria (blue-green algae) are a unique group of photosynthetic bacteria amongst the oldest forms of life, which widespread in aquatic environments including freshwater lakes, rivers and reservoirs. Furthermore, they have ability to produce a wide range of secondary metabolites with toxic property for aquatic animals, as well as human beings. Considering the importance of cyanobacteria in public health, the introduction of sensitive and reliable methods for their detection is the main aim of this study. In the present study, 30 water samples were collected from six locations of the Kor River, Iran. The samples were analyzed for the prevalence of cyanobacterial species using conventional culture methods and morphological tests. Then, molecular identification of the isolates was performed by the comparative evaluation of three sets of primers (CYA106/CYA781; CYA781/CYA359; and PCα/PCβ). Furthermore, their abilities to produce cyanobacterial toxins including microcystin and nodularin synthetase enzyme complexes were investigated by using polymerase chain reaction method. The results obtained from this study indicated that two isolates were identified as Cyanobacterium aponinum and Phormidium sp. none of the isolates had ability to produce selected toxins. In addition, the results indicated that the selected pair primers were proper for detection of the isolates. Hence, due to importance of cyanobacterial isolation from water samples and their effect on human health, periodic studies in different water resources and regions seem necessary. Furthermore, among the selected primers, CYA106/CYA781 could be a proper primer pair for detection of cyanobacterial isolates.

Evolutionary Changes in DnaA-Dependent Chromosomal Replication in Cyanobacteria.

Replication of the circular bacterial chromosome is initiated at a unique origin (oriC) in a DnaA-dependent manner in which replication proceeds bidirectionally from oriC to ter. The nucleotide compositions of most bacteria differ between the leading and lagging DNA strands. Thus, the chromosomal DNA sequence typically exhibits an asymmetric GC skew profile. Further, free-living bacteria without genomes encoding dnaA were unknown. Thus, a DnaA-oriC-dependent replication initiation mechanism may be essential for most bacteria. However, most cyanobacterial genomes exhibit irregular GC skew profiles. We previously found that the Synechococcus elongatus chromosome, which exhibits a regular GC skew profile, is replicated in a DnaA-oriC-dependent manner, whereas chromosomes of Synechocystis sp. PCC 6803 and Nostoc sp. PCC 7120, which exhibit an irregular GC skew profile, are replicated from multiple origins in a DnaA-independent manner. Here we investigate the variation in the mechanisms of cyanobacterial chromosome replication. We found that the genomes of certain free-living species do not encode dnaA and such species, including Cyanobacterium aponinum PCC 10605 and Geminocystis sp. NIES-3708, replicate their chromosomes from multiple origins. Synechococcus sp. PCC 7002, which is phylogenetically closely related to dnaA-lacking free-living species as well as to dnaA-encoding but DnaA-oriC-independent Synechocystis sp. PCC 6803, possesses dnaA. In Synechococcus sp. PCC 7002, dnaA was not essential and its chromosomes were replicated from a unique origin in a DnaA-oriC independent manner. Our results also suggest that loss of DnaA-oriC-dependency independently occurred multiple times during cyanobacterial evolution and raises a possibility that the loss of dnaA or loss of DnaA-oriC dependency correlated with an increase in ploidy level.

Application of anaerobic bacterial ammonification pretreatment to microalgal food waste leachate cultivation and biofuel production

Food waste constitutes the largest component of municipal solid waste in many urbanized societies. The current practice of disposing of biodegradable food waste mixed with other solid wastes to landfills is not sustainable and is environmentally undesirable. Moreover, the leakage of nutrient-rich food waste leachate (FWL) impacts the environment by eutrophication of the water body. Two robust microalgal species, Dunaliella tertiolecta (D. tertiolecta) and Cyanobacterium aponinum (C. aponinum), have been selected previously for the treatment of FWL because they can tolerate diluted FWL. However, growth suppression by some inhibiting factors, such as total suspended solids and organic nitrogen, limited biomass productivity, and substantial dilution (5–10% v/v FWL) was required. To alleviate this suppression, anaerobic bacterial digestion was proposed to pretreat FWL and convert certain nutrients such as organic nitrogen to ammonium. The pretreatment was optimized in neutral to slightly alkaline media, where a byproduct of biomethane up to 4.67 L methane/kg COD was produced. In addition, digestate after anaerobic ammonification can provide sufficient inorganic nutrients for subsequent microalgal biofuel production. Through batch cultivation, 50% (v/v) of anaerobic bacterial pretreated FWL digestate can be fed to D. tertiolecta, with biomass productivity of up to 0.88 g/L/day, and biomass productivity can be increased to 0.34 g/L/day for C. aponinum at 30% FWL digestate. Regarding the nutrient removal efficiency, 98.99% of total nitrogen and 65% of total phosphorus can be removed by D. tertiolecta, whereas more than 80% of total nitrogen and 65% of total phosphorus can be removed by C. aponinum. The use of anaerobic bacterial ammonification pretreatment can significantly improve the performance of subsequent microalgal treatments and has been shown to be a sustainable green technology for biofuel production and FWL recycling.

Stoichiometrically balanced nutrient management using a newly designed nutrient medium for large scale cultivation of Cyanobacterium aponinum

Cyanobacteria have tremendous potential to produce bioactive molecules, which makes them a highly lucrative organism for use in industrial applications. In the present study, the first commercial nutrient medium for Cyanobacterium aponinum is developed and a process for large scale cultivation of cyanobacteria is established by combining economical medium, pre-emptive nutrient feeding strategy, and semi-continuous mode (SCM) of cultivation. The parameters measured were growth in terms of OD750 biomass, total nitrogen, nitrate, and phosphorous. Results indicated 13% more biomass yield in urea-phosphoric acid medium (UPA), in comparison to blue-green medium (BG-11). Biomass concentration was 5.3 and 4.7 g L−1 with UPA and BG-11 media, respectively. Urea was found to be a preferred nitrogen source for C. aponinum. Nutrient-dosing studies with UPA medium in SCM of operation resulted in an average daily biomass productivity of ~ 0.44 g L−1 day−1, which is significantly higher than those reported in previous studies. Here, the stoichiometric requirement of nitrogen and phosphorous was found to be 31 mg L−1 and 4.5 mg L−1, respectively. Stoichiometric nutrient addition in SCM resulted in a reduction in nutrient loss in blow down. In addition, the outdoor scale-up studies in flat panel photobioreactors further established the efficacy of UPA medium. Cost analysis of media revealed that UPA medium is 4.4 times less expensive than BG-11 and hence is a suitable and economical medium for large scale cultivation of C. aponinum. Further, this nutrient feeding strategy has wider applications which can be extended to other algal strains and cultivation systems.

Exopolysaccharides from Cyanobacterium aponinum induce a regulatory dendritic cell phenotype and inhibit SYK and CLEC7A expression in dendritic cells, T cells and keratinocytes

Regular bathing in the Blue Lagoon has beneficial effects on psoriasis. Previously, we showed that exopolysaccharides (EPS-Ca) secreted by Cyanobacterium aponinum, a dominating organism in the Blue Lagoon, increased IL-10 secretion by human dendritic cells (DCs). In addition, co-culturing allogeneic CD4+ T cells with DCs matured in the presence of EPS-Ca increased differentiation of T cells into T regulatory cells at the cost of the disease inducing Th17 cells. In the present study, EPS-Ca increased the proportion of DCs expressing CD141, a surface molecule linked to regulatory DCs, and the CD141+ cells secreted more IL-10 than the CD141− cells. EPS-Ca decreased T cell secretion of IL-17, IL-13 and IL-10 and the proportion of T cells expressing the activation marker CD69 that has also been linked to lymphocyte retention. In addition, EPS-Ca reduced keratinocyte secretion of CCL20 and CXCL10, chemokines implicated in recruitment of inflammatory cells. EPS-Ca decreased DC expression of Dectin-1/CLEC7A and SYK, keratinocyte expression of CLEC7A, SYK and CAMP (the gene for LL37), and T cell expression of phosphorylated Zap70. These results indicate that EPS-Ca may induce a regulatory phenotype of DCs, T cells that are less active/inflammatory and less prone to being retained in the skin, and keratinocytes that induce less recruitment of inflammatory cells to the skin and that these effects may be mediated by the effects of EPS-Ca on CLEC7A and SYK. Overall the results indicate that EPS-Ca may be involved in the beneficial effects psoriasis patients experience when bathing in the Blue Lagoon.