Spirulina Cells Research Articles

Effect of Fermentation on Enhancing the Nutraceutical Properties of Arthrospira platensis (Spirulina)

Arthrospira platensis (spirulina), a filamentous fresh-water planktonic cyanobacterium, possesses diverse biological activities and a unique nutritional profile, due to its high content of valuable nutrients. This study aimed to further improve the bioactive profile of spirulina, by fermenting it with the lactic acid bacterium Lactobacillus plantarum. In vitro comparison of the total phenolic content (TPC), C-phycocyanin, free methionine, DPPH radical scavenging capacity, ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and protein fragmentation via SDS-PAGE in untreated versus 12 to 72 h fermented spirulina is reported here. After 36 h fermentation, TPC was enhanced by 112%, FRAP by 85% and ORAC by 36%. After 24 h, the DPPH radical scavenging capacity increased 60%, while the free methionine content increased by 94%, after 72 h. Past 36 h of fermentation, the total antioxidant capacity (TAC) diminished, possibly due to deterioration of the heat-sensitive antioxidants. However, protein fragmentation and free methionine content increased, linearly, with the fermentation time. Cyanobacterial peptides and other bioactive compounds trapped within the spirulina cell wall are released during fermentation and have a significant potential as a functional ingredient in nutraceuticals and pharmaceuticals, in addition to their nutritive value.

Molecular cargo delivery using multicellular magnetic microswimmers

The recent emergence of versatile micro/nanorobots provides new strategies of healthcare and disease treatment, especially for targeted delivery of therapeutic agents to otherwise inaccessible regions. However, for successful translation of laboratory microrobotic tools into clinical outcomes, critical challenges still remain, such as controllable cargo loading/release on site, robust spatiotemporal navigation in real time and reliable biocompatibility/biodegradation inside the body. Herein, we report the loading, transport and release of molecular cargos using cell-based magnetic microswimmers engineered from multicellular Spirulina. The loading is attained by harnessing the dehydration and rehydration of Spirulina cells, inside which model macromolecules are encapsulated as a discrete phase, and for small molecules, as a continuous phase. Driven by low-strength magnetic fields, the molecule-laden swimmer manages to perform navigation in an intestinal tract mimicry, imitating the process of guest-molecule transport in the gastrointestinal tract. The loaded molecules can be released from the swimmer through host degradation and/or concentration gradient-driven diffusion, with the speed of release tailored by the magnetite-coating thickness. Furthermore, evaluation tests in a stem-cell system infer that the bioactivity of the guest molecules remains intact after the loading-release procedure. In summary, we have demonstrated a feasible approach for gastrointestinal delivery of molecular agents using cell-based microswimmers.

Phyco-based synthesis of TiO2 nanoparticles and their influence on morphology, cyto-ultrastructure and metabolism of Spirulina platensis

The characterization of phyco-based synthesis of TiO2 NPs from Spirulina platensis (GSSp.TiO2 NPs) and the effect of such biosynthesized nanoparticles on morphology, growth, ultrastructure and enzymatic of the same alga have been studied. These nanoparticles have a good solubility, are stable in water and the average size was 17.3 nm. GSSp.TiO2 NPs aggregated and adsorbed on S. platensis membrane. Penetration and entrance of the nanoparticles into the Spirulina cells were also recorded which stimulated cell wall deformity, plasmolysis, and damage to both cell wall and plasma membrane, combined with the appearance of notch-like structure. A positive significant correlation was recorded between all applied concentrations of the biosynthesized nanoparticles and the antioxidant activities (CAT and APX) and LOX. More than 160 mg/l of GSSp.TiO2 NPs have a harmful impact on S. platensis, so nanoparticles have to be managed before disposal to protect our health and ecosystem.

Transcriptome Analysis of Phycocyanin-Mediated Inhibitory Functions on Non-Small Cell Lung Cancer A549 Cell Growth.

Phycocyanin (PC), derived from cyanobacteria and Spirulina cells, is a type of natural antineoplastic marine protein. It has been reported that phycocyanin exerts an antitumor function in non-small cell lung cancer (NSCLC) cells, but the underlying mechanism has not been elucidated. In this research, a transcriptome study was performed to investigate the regulatory mechanisms of phycocyanin on human NSCLC A549 cells. The survival rate and proliferation ability of A549 cells were markedly reduced by phycocyanin, along with abnormal morphologic changes. The transcriptome analysis showed that 2970 genes were differentially expressed after phycocyanin treatment in A549 cells, including 1431 down-regulated and 1539 up-regulated genes. Gene ontology and KEGG analysis suggested that some classical pathways, such as Wnt, NF-κB, and PI3K-AKT signaling, were significantly enriched. Strikingly, protein–protein interaction (PPI) analysis showed that ubiquitin-C (UBC) occupied the highest degree (the highest number of interactions) in differential genes, indicating that it might play a key role in the phycocyanin-mediated regulatory process in A549 cells. Moreover, qRT-PCR results showed consistent expression trends of differential genes with transcriptome analysis. Consequently, this study has provided a theoretical basis for regulation of phycocyanin in A549 cells, which lays a foundation for the treatment of NSCLC.

Blue-green alga Spirulina as a tool against water pollution by 1,1'-(2,2,2-trichloroethane-1,1-diyl)bis(4-chlorobenzene) (DDT)

Abstract The presented work concerns studying a possibility of using blue-green alga (cyanobacteria) Spirulina for cleaning water polluted with DDT (1,1'-(2,2,2-trichloroethane-1,1-diyl)bis (4-chlorobenzene)). For this aim, at first the influence of different concentrations of DDT (1, 10 and 50 ppm) on the ability of growing of Spirulina and the intensity of uptake of DDT by blue-green alga have been investigated. In parallel, the penetration of tested toxicant into Spirulina cells and the influence on cell ultrastructure by using electron microscopic method have been studied. The obtained results show that DDT easily penetrated Spirulina cells and caused partial destruction of organelles. According to obtained data, 10 ppm is acceptable concentration of DDT for Spirulina growing in polluted water. Finally, the model large-scale experiment in reservoir with volume 40 L for testing possibility of using Spirulina to clean artificially polluted water have been carried out. The obtained results have been shown that after 15 days of incubation Spirulina removes approximately 70% of DDT from polluted water. These results can become a basis for development of a new phytoremediation technology for cleaning of DDT-polluted waters based on application of Spirulina.

A rapid and non-destructive method for quantifying biomolecules in Spirulina platensis via Fourier transform infrared – Attenuated total reflectance spectroscopy

This study aimed to develop a method to rapidly quantify biomolecules in Spirulina platensis. Fourier transform infrared (FTIR) spectra of Spirulina cells were modeled from the individual spectra of glucose, bovine serum albumin and glycerol tripalmitate standards by iterative spectral subtraction and addition methods in accordance with the Beer-Lambert's law. Multipoint regression and partial least squares (PLS) regression techniques were used to create separate regression models for protein, carbohydrate and lipid analysis. These models were made within the characteristic wavenumbers of target biomolecules. The predictive power of the regression models was characterized by coefficient of determination (R2), root mean square error of prediction (RMSEP), residual predicted deviation (RPD), and relative error. Results from regression models were also compared to conventional biochemical methods using appropriate mean comparison technique. Results show that PLS models for protein, carbohydrate, and lipids have higher R2 and RPD and lower RMSEP and relative error than multipoint regression. Furthermore, algal composition predicted by PLS-regression are statistically similar to the composition determined via conventional methods. Both regression methods have poor predictive power for lipid content as illustrated by RPD < 1.5 and relative error ≥ 70%. This may be due to indistinct absorbance of the CO ester characteristic band owing to overlaps with the tail of amide I band and due to low lipid content of Spirulina sp. Nevertheless, FTIR spectroscopy coupled with PLS-regression technique proves to be a fast, non-destructive and reliable method in quantifying biomolecules in Spirulina.

Mutation of Spirulina sp. by nuclear irradiation to improve growth rate under 15% carbon dioxide in flue gas

Spirulina sp. was mutated by γ-rays from 60Co nuclear irradiation to improve growth and CO2 fixation rate under 15vol.% CO2 (in flue gas from a power plant). Mutants with enhanced growth phenotype were obtained, with the best strain exhibiting 310% increment in biomass yield on day 4. The mutant was then domesticated with elevated CO2 concentration, and the biomass yield increased by 500% after domestication under 15vol.% CO2, with stable inheritance. Ultrastructure of Spirulina sp. shows that the fractal dimension of Spirulina cells decreased by 23% after mutation. Pore size in the cell wall of Spirulina mutant increased by 33% after 15vol.% CO2 domestication. This characteristic facilitated the direct penetration of CO2 into cells, thus improving CO2 biofixation rate.

A chiral microwave absorbing absorbent of Fe–CoNiP coated on spirulina

A chiral bio-absorbent of Fe–CoNiP coated on the spirulina was fabricated by the electroless and chemical vapor decomposition. The scanning electron microscopy (SEM) was used to evaluate the spirulina cells particle morphology. X-ray diffraction (XRD) patterns were done to analyze the particle crystal grain structure. The permittivity and permeability was measured by a vector network analyzer in frequency 8–18 GHz, and the reflection loss (RL) was calculated. The results showed the carbonyl iron particles (CIPs) and CoNiP were bonded to the spirulina surface, the permittivity and permeability could be enlarged as Fe films coated on the particles compared with the CoNiP spirulina, it was attributed to the excellent electromagnetic property of CIPs. The chiral Fe–CoNiP composites had a better absorbing property at 8–18 GHz than the CoNiP spirulina composite, the RL was −16.26 dB at 10.48 GHz, the absorbing band was 9.5–11.5 GHz of RL less than −10 dB, which indicated the Fe–CoNiP spirulina could be an effective absorbent used in 8–18 GHz.

Anaerobic digestion of Spirulina sp. and Scenedesmus sp.: a comparison and investigation of the impact of mechanical pre-treatment

Anaerobic digestion (AD) is a unit process that integrates beneficially and sustainably into many bioprocesses. This study assesses and compares the production of methane from the biomass of the microalga Scenedesmus sp. and the cyanobacterium Spirulina sp. in batch anaerobic digesters. Anaerobic digestion of whole cell Spirulina resulted in a substantially higher methane productivity (0.18 L CH4 Lreactor −1 day−1) and methane yield (0.113 L CH4 g−1 volatile solids (VS)) compared to the digestion of whole cell Scenedesmus (0.12 L CH4 Lreactor −1 day−1 and 0.054 L CH4 g VS−1). Spirulina, possibly due to a combination of osmotic shock, the filamentous nature of the cells and lower mechanical strength of the non-cellulosic cell wall, was more readily degraded by hydrolytic and acidogenic microorganisms, resulting in the generation of a greater amount of acetic acid. This in turn provided greater substrate for methanogens and hence higher methane yields. In addition, Spirulina cells could be disrupted mechanically more quickly (1 h) than Scenedesmus cells (4 h) in a bead mill. Mechanical pre-treatment improved the final methane yields (L CH4 g VS−1) obtained from digestion of both substrates; however, the improvement was greater for Scenedesmus. Mechanical pre-treatment resulted in a 47 % increase in methane production for Spirulina compared to 76 % increase for Scenedesmus fed digesters. The more substantial increase observed for Scenedesmus was due to the relatively inefficient digestion of the whole, unruptured cells.

Biosorption characteristics of Spirulina and Chlorella cells to accumulate heavy metals

The heavy metal biosorption of dried Chlorella vulgaris and Spirulina platensis-Spirulina maxima cells was studied under various experimental conditions. The effect of biosorbent dosage, pH, adsorption time, temperature, initial metal concentration on biosorption was studied. Biosorption process can be divided into two parts: the first part follows zero-order, the second part pseudo second-order kinetics. Characterization of biosorption equilibrium was evaluated with Langmuir and Dubinin-Radushkevich models using non-linear regression. The optimum pH range was found to be 5.0 ? 6.0 for Pb(II) and 4.0 ? 6.0 for Cu(II) and Cd(II) adsorption. The maximum adsorption capacities for Pb(II), Cd(II) and Cu(II) were 144, 161 and 138 mg g-1 by Chlorella cells and 370, 201 and 165 by Spirulina cells, based on the experimental data. The same values for activated carbon were 86, 134 and 43 mg g-1, respectively.

Application of the lipofection method to transform gene into the cells of the cyanobacterium - species Spirulina platensis

Spirulina platensis was a commercially cultured cyanobacterium spcies, having biomass up to 3.000 tons in a year and used as health food and animal feed. If we could draw its potential, we could apply S. platensis to solve environment problems. S. platensis produced valuable materials such as g-linolenic acid, bioplastic etc. To increase the content of these materials, the recombinant DNA technique was most important, but its application has just been started. At present, to transform gene into Spirulina cells, only the electroporation method was applied for this purpose. The lipofection method was used widely for transfection. It had advantages for its convenience, efficiency and safety but its application was limited to culture mammalian cells. Recently, we found E. coli and S. platensis could be transformed by lipofection method. We investigated conditions to transform S. platensis with DOTAP liposomal transfection reagents. We used the pHSG397 vector with cat to transform S. platensis. The transformed Spirulina cells could survive in the condition of chloramphenicol concentration more than 0.5 mg/ml for 4 weeks. The transformation efficiency of the lipofection method was 4 - 15 times better in comparison with the electroporation method, dependently on applied vetors (such as close or open vector cutted used by the enzyme EcoRI).

Potential of Various Biosorbents for Zn(II) Removal

The adsorption capacities of six biosorbents (Pseudomonas aeruginosa, Pseudomonas fluorescens, Escherichia coli, Chlorella vulgaris, and Spirulina platensis) for Zn(II) ions under batch condition have been studied. The optimum pH range was found to be 5.0−6.0. The amount of adsorbed Zn(II) ions were between 18 and 128 mg/g. Characterization of biosorption equilibrium was evaluated with Langmuir and Dubinin-Radushkevich model using non-linear regression. The adsorption capacities of Ca-alginate, chitosan, and immobilized Spirulina platensis-maxima cells were also determined in packed-bed column in continuous system. The results show, free Spirulina cells have the highest adsorption capacity for Zn(II) ions (128 mg/g). The chitosan-Spirulina system has slightly decreased adsorption capacity 98 mg/g per dry weight content. Thomas and Yoon-Nelson models were fitted for the evaluation of experimental data.

Influence of carbon-dioxide on the growth of Spirulina sp. (MCRC-A0003) isolated from Muttukadu backwaters, South India.

Growth of Spirulina sp. (MCRC-A0003), a cyanobacterium, was evaluated under different concentrations of carbon-dioxide (CO2) (4-50 %) in a closed glass photobioreactor. Although significant CO2 utilization by the cyanobacterial strain was observed up to 50 % concentration, complete utilization was observed only at 4, 10 and 20 % concentrations on 3rd, 6th and 8th day respectively. However, considerable reduction was witnessed in reactors containing 30-50 % CO2 only between 6th and 9th day. A corresponding increase in the biomass and primary metabolites like chlorophyll-a, carbohydrate and protein were observed. Biomass productivity of Spirulina in reactors sparged with 4, 10 and 20 % CO2 were 13.7, 43 and 44 % more than that in control reactor without CO2. While CO2 increased the levels of primary metabolites in the cyanobacterial cells, it was quite prominent in 10 % CO2 concentration with the chlorophyll-a, carbohydrate and protein contents were 64, 183 and 626 mg g(-1) respectively. While 10 and 6.6 % increase were noticed in chlorophyll-a and protein, 17 % increase in carbohydrate levels was observed in Spirulina cells, which could be attributed to the conversion of CO2 to carbohydrate by the cyanobacterium.

Fabrication and electromagnetic interference shielding effectiveness of polymeric composites filled with silver-coated microorganism cells

Abstract In this paper, helical silver-coated Spirulina cells were used as conductive fillers for the fabrication of polymeric composites. The morphology and composition of the coated Spirulina cells were analyzed with scanning electron microscope and energy dispersive X-ray spectrometer. The densities of silver-coated Spirulina cells were measured using the standard Archimedes method with distilled water. The electrical resistivity was measured by four-probe technique using ammeter and voltmeter whereas electromagnetic interference shielding effectiveness was measured by four-port method using vector network analyzer and coaxial-airline sample holder. The results showed that the silver-coated Spirulina cells with different coating thickness were lightweight fillers compared to the other typical conductive particles. The polymeric composites could achieve good conductivity at the lower content of silver-coated Spirulina cells owing to their helical shape. The shielding effectiveness of polymeric composites had a strong dependence on their conductivity. At the coating thickness of 0.96 μm and the content of 40 vol%, the shielding effectiveness could reach above 74.3 dB in entire test wave band.

Biotechnology of Metal Removal from Industrial Wastewater: Zinc Case Study

The time‐dependent biosorption capacity of microalga Spirulina platensis for zinc removal from wastewater of the machinery company Moldagrotehnica was studied. The maximal sorption of zinc was achieved after 30 min of reaction. Zinc concentration in wastewater was determined by atomic absorption spectrometry and in dry biomass using neutron activation analysis. In addition to Zn, Spirulina cells accumulate from wastewater considerable amounts of other heavy metals such as As, Fe, Sb, and W.

Evaluation of Spirulina platensis Resistance to Different Antibiotics to Find a Selectable Marker for Genetic Transformation

marker is needed. Objectives: The purpose of this study was to determine a suitable selection marker for Spirulina platensis. Thus, this experiment was designed to survey the response of Spirulina to different concentrations of candidate antibiotics including kanamycin, hygromycin, phosphinothricin, chloramphenicol and streptomycin in standard Zarrouk medium. Materials and Methods: S. platensis culture matched to 1 McFarland standard and its resistance to different antibiotics was studied by serial dilution of kanamycin, hygromycin, phosphinothricin, chloramphenicol and streptomycin. Biomass was detected after 7days using spectrophotometer and related growth graphs were illustrated. Results: Fresh culture of S. platensis reached to exponential phase on day 4 of experiment. While this phase was presented on day 5 for cultures containing kanamycin or hygromycin. The Spirulina cultured in medium supplied with basta, did not reach to growth phase however, chloramphenicol can stop the growth of Spirulina cells. Spirulina showed resistance to streptomycin with the concentration of 40 mg/L and higher. Therefore, streptomycin can use as selectable marker to detect GM (Genetic Modified) Spirulina spp. Conclusions: The streptomycin can be used as suitable selection marker in comparison with other introduced markers. For using this selectable marker, integration of a streptomycin resistant gene is needed. The gene aadA is a potential candidate. The aadA gene can be expressed under the control of upstream and downstream elements of S. platensis.

Acoustic, electrochemical and microscopic characterization of interaction of Arthrospira platensis biofilm and heavy metal ions

This study examines a biofilm of Arthrospira platensis and its interactions with cadmium and mercury, using electrochemical admittance spectroscopy technique combined with highly sensitive Love wave platform for the real-time detection in liquid medium. Spirulina cells were immobilized via multilayers of polyelectrolyte (PEM) on Si/SiO2 surface of both transducers and characterized using atomic force microscopy (AFM). Scanning electron microscopy (SEM) cell images revealed a first defense mechanism against cadmium at 10−12M and it immediately takes place after 4s from injection. The cyanobacteria biofilm becomes more conductive, due to an increase of polyphosphate bodies. An increase of density induces a decrease of frequency. Response time τ90% of the biofilm toward Cd2+ was between 6 and 8min, while it did not exceed a few seconds toward Hg2+ at 10−12M. However, the initial rapid stage of mercury adsorption took 40s to reach the saturated stage. Once external sorption reached the saturated stage, internal mercury uptake began; cations were transported across the cell membrane into the cytoplasm and a beta-HgS precipitation took place, inducing conductivity biofilm decrease, and generating an increase of density, and thus a frequency decrease. SEM images revealed the beginning cell damage at 10−06M of cadmium and mercury.

Fabrication and electromagnetic properties of soft-core functional particles by way of electroless Ni–Fe–P alloy plating on helical microorganism cells

In order to fabricate lightweight heteromorphic filler particles with excellent electromagnetic properties, Spirulina platensis were used as templates to produce helical soft-core functional particles by way of electroless plating of Ni–Fe–P alloy. The morphologies and ingredients of the coated Spirulina cells were analyzed with scanning electron microscopy and energy dispersive spectrometer respectively. The coating structures were characterized by employing the X-ray diffraction. The electromagnetic parameters (complex permittivity and complex permeability) of samples containing the coated Spirulina cells before and after heat treatment were measured by a vector network analyzer. The results showed that the Spirulina cells were deposited with Ni–Fe–P coating by electroless plating and kept their initial helical shape perfectly after plating. The effects of the content of P and the mass ratio of Ni:Fe in the particle surface coating on the surface qualities and electromagnetic properties of the coated Spirulina cells were also studied in detail, which showed that lower P content and suitable Ni:Fe ratio is more preferable for better coating quality and electromagnetic properties of the as-prepared particles. And heat treatment can further improve the electromagnetic properties of the coated Spirulina cells, since heat treatment can bring phase transformation of the coating and reduce structural imperfections.

Electrical resistivity and dielectric properties of helical microorganism cells coated with silver by electroless plating

In this paper, microorganism cells (Spirulina platens) were used as forming templates for the fabrication of the helical functional particles by electroless silver plating process. The morphologies and ingredients of the coated Spirulina cells were analyzed with scanning electron microscopy and energy dispersive spectrometer. The crystal structures were characterized by employing the X-ray diffraction. The electrical resistivity and dielectric properties of samples containing different volume faction of sliver-coated Spirulina cells were measured and investigated by four-probe meter and vector network analyzer. The results showed that the Spirulina cells were successfully coated with a uniform silver coating and their initial helical shapes were perfectly kept. The electrical resistivity and dielectric properties of the samples had a strong dependence on the volume content of sliver-coated Spirulina cells and the samples could achieve a low percolation value owing to high aspect ratio and preferable helical shape of Spirulina cells. Furthermore, the conductive mechanism was analyzed with the classic percolation theory, and the values of ϕc and t were obtained.

Fabrication and electromagnetic properties of bio-based helical soft-core particles by way of Ni–Fe alloy electroplating

Ni–Fe alloy electroplating was used as a bio-limited forming process to fabricate bio-based helical soft-core ferromagnetic particles, and a low frequency vibration device was applied to the cathode to avoid microorganism (Spirulina platens) cells adhesion to the copper net during the course of plating. The morphologies and ingredients of the coated Spirulina cells were characterized using scanning electron microscopy and energy dispersive spectrometer. The complex permittivity and permeability of the samples containing the coated Spirulina cells before and after heat treatment were measured and investigated by a vector network analyzer. The results show that the Spirulina cells after plating keep their initial helical shape, and applying low frequency vibration to the copper net cathode in the plating process can effectively prevent agglomeration and intertwinement of the Spirulina cells. The microwave absorbing and electromagnetic properties of the samples containing the coated Spirulina cells particles with heat treatment are superior to those samples containing the coated Spirulina cells particles without heat treatment.