Bioactive compound production by thermophilic and thermotolerant cyanobacteria (blue-green algae)

A thermotolerant species of Phormidium produced extracellular anti-microbial material during batch culture. Although this material was inactive when screened against a number of other cyanobacteria, it inhibited the growth of a wide range of Gram-positive and Gram-negative heterotrophic bacteria, Candida albicans and Cladosporium resinae.The authors are with the Department of Biological Sciences, University of Dundee, Dundee DD1 4HN, UK     

Hemagglutination method for detection of freshwater cyanobacteria (blue-green algae) toxins.

Strains of the freshwater cyanobacteria (blue-green algae) Anabaena flosaquae and Microcystis aeruginosa produced toxins that caused intermittent but repeated cases of livestock, waterfowl, and other animal deaths. They also caused illness, especially gastrointestinal, in humans. The most common group of toxins produced by these two species were peptide toxins termed microcystin, M. Aeruginosa type c, and anatoxin-c. A method was found to detect the toxins which utilizes their ability to cause agglutination of isolated blood cells from mice, rats, and humans. The method could detect the toxin in samples from natural algal blooms, laboratory cultures, and toxin extracts. The method consists of: (i) washing lyophilized cyanobacteria cells with physiological saline (0.9% NaCl), (ii) centrifuging the suspension and then mixing portions of the cell-free supernatant with equal volumes of saline-washed erythrocytes in V-shaped microtiter plates, (iii) allowing the mixture to stand for 3 to 4 h, and (iv) scoring the presence of the toxin as indicated by blood cell agglutination. Nontoxic strains, as determined by intraperitoneal mouse bioassay of cyanobacteria or green algae, did not produce an agglutination response.     

Biodegradation of dyes by some green algae and cyanobacteria

The ability of Chlorella vulgaris, Lyngbya lagerlerimi, Nostoc lincki, Oscillatoria rubescens, Elkatothrix viridis and Volvox aureus to decolorize and remove methyl red, orange II, G-Red (FN-3G), basic cationic, and basic fuchsin was investigated. These algae showed different efficiency for colour removal; varied from 4 to 95% according to the algal species, its growth state and the dye molecular structure. Basic cationic and basic fuchsin were the most susceptible dyes for decolorisation and removal by all algae being tested, and up to 82% of methyl red was also removed by N. lincki and O. rubescens. However, the algal activity to decolorize orange II and G-Red was markedly fluctuated and lower. C. vulgaris displayed activity to remove 43.7 and 59.12% while as V. aureus removed 5.02 and 3.25% of the added dyes respectively. The results also showed that treatment of either C. vulgaris or N. Linckia with G-Red or methyl red, respectively, induced the algal azo dye reductase enzyme by 72 and 71% at the same order.     

A review of the alien and expansive species of freshwater cyanobacteria and algae in the Czech Republic

The invasion and spread of non-native species of many different kinds of organisms is of increasing interest to researchers. Invasions by microscopic organisms, however, are poorly understood, and their impact on the environment is probably underestimated. We collected available data on non-native and invasive/expansive algae and cyanobacteria in the Czech Republic; we mapped their distribution and assessed their impact on local species and other real or potential risks resulting from their spread. The list of alien species in the Czech Republic contains 10 species of cyanobacteria, 9 species of Bacillariophyceae, 1 species of Dinophyta, 1 species of Ulvophyceae, 2 species of Chlorophyceae, and 1 species complex of Zygnematopyceae. The literature on the worldwide occurrence of these taxa is also reviewed.     

Biochemical and genetic engineering strategies to enhance hydrogen production in photosynthetic algae and cyanobacteria

As an energy carrier, hydrogen gas is a promising substitute to carbonaceous fuels owing to its superb conversion efficiency, non-polluting nature, and high energy content. At present, hydrogen is predominately synthesized via chemical reformation of fossil fuels. While various biological methods have been extensively explored, none of them is justified as economically feasible. A sustainable platform for biological production of hydrogen will certainly impact the biofuel market. Among a selection of biological systems, algae and cyanobacteria have garnered major interests as potential cell factories for hydrogen production. In conjunction with photosynthesis, these organisms utilize inexpensive inorganic substrates and solar energy for simultaneous biosynthesis and hydrogen evolution. However, the hydrogen yield associated with these organisms remains far too low to compete with the existing chemical systems. This article reviews recent advances of biochemical, bioprocess, and genetic engineering strategies in circumventing technological limitations to hopefully improve the applicative potential of these photosynthetic hydrogen production systems.     

Kinetics of nitrate uptake by freshwater algae

The kinetics of nitrate (NO₃ ^–) uptake, the maximum uptake velocity (V_m) and the half-saturation constant (K_s), were determined for 18 species of batch-cultured freshwater algae grown without nitrogen limitation. Values of K_s ranged from 0.25 to 6.94 µM l^–1 Chlorella pyrenoidosa Chick, and Navicula pelliculosa (Breb.) Hilse, respectively. Values of V_m ranged from 0.51 to 5.07 µM l^–1 h^–1 for Anabaena A7214 and Nitzschia W-32 O'Kelley, respectively. The mean positive values of K_s for Chlorophyta, Cyanophyta and Chrysophyta were 1.89, 3.67 and 4.07 µM l^–1, respectively. The mean values of V_m for the same phyla were 1.61, 1.02 and 2.97 µM l^–1 h^–1 10⁵ cells^–1, respectively. The ranges of these kinetic parameters encompass values of kinetic parameters for marine and freshwater species in batch culture, for freshwater algae grown in N-limited chemostats and for natural populations of freshwater phytoplankton. Thus, in spite of variability between species, uptake parameters for both marine and freshwater algae are identical.     

Identification of teratogenic polymethoxy-1-alkenes from Cylindrospermopsis raciborskii,and taxonomically diverse freshwater cyanobacteria and green algae

Cylindrospermopsis raciborskii is among the most commonly recognized toxigenic cyanobacteria associated with harmful algal blooms (HAB) in freshwater systems, and specifically associated with multiple water-soluble toxins. Lipophilic metabolites from C. raciborskii, however, were previously shown to exert teratogenicity (i.e. inhibition of vertebrate development) in the zebrafish (Danio rerio) embryo model, specifically suggesting the presence of additional bioactive compounds unrelated to the currently known toxins. In the present study, a series of known teratogenic polymethoxy-1-alkenes (PMA) were identified, purified and chemically characterized from an otherwise well-characterized strain of toxigenic C. raciborskii. Although PMA have been previously identified in other cyanobacteria, this is the first time they have been identified from this recognized HAB species. Following their identification from C. raciborskii, the taxonomic distribution of the PMA was additionally investigated by chemical screening of a freshwater algal (i.e. cyanobacteria, green algal) culture collection. Screening suggests that these compounds are distributed among phylogenetically diverse taxa. Furthermore, parallel screening of the algal culture collection, using the zebrafish embryo model of teratogenicity, the presence of PMA was found to closely correlate with developmental toxicity of these diverse algal isolates. Taken together, the data suggest PMA contribute to the toxicity of C. raciborskii, as well as apparently several other taxonomically disparate cyanobacterial and green algal genera, and may, accordingly, contribute to the toxicity of diverse freshwater HAB.     

Maximizing hydrogen production by cyanobacteria

When incubated anaerobically, in the light, in the presence of C2H2 and high concentrations of H2, both Mo-grown Anabaena variabilis and either Mo- or V-grown Anabaena azotica produce large amounts of H2 in addition to the H2 initially added. In contrast, C2H2-reduction is diminished under these conditions. The additional H2-production mainly originates from nitrogenase with the V-enzyme being more effective than the Mo-protein. This enhanced H2-production in the presence of added H2 and C2H2 should be of interest in approaches to commercially exploit solar energy conversion by cyanobacterial photosynthesis for the generation of molecular hydrogen as a clean energy source.     

Nitrous oxide production by cyanobacteria

Evidence is presented here that axenic cultures of Nostoc spp., Aphanocapsa (PCC 6308), and Aphanocapsa (PCC 6714) but not Anacystis nidulans R-2 (PCC 7942) produce N₂O and ammonia when grown on nitrite. The data suggest that the cyanobacteria produce N₂O by nitrite reduction to ammonia.Nonstandard abbreviations DCMU 3-(3,4-dichlorophenyl)-1,1-dimethyl urea - NIR nitrite reductase     

Biosynthesis of delta-aminolevulinic acid by blue-green algae (cyanobacteria).

When levulinic acid, a competitive inhibitor of delta-aminolevulinic acid dehydratase, was added to growing cultures of blue-green algae (cyanobacteria), delta-aminolevulinic acid was excreted into the medium and cell growth was inhibited.     

Airborne dispersal of antarctic terrestrial algae and cyanobacteria

The dispersal of algae and cyanobacteria at three Antarctic fellfield sites was investigated using microscopic and culture analysis of samples from active and passive air samplers Intersite variation in the mean number of large algal propagules (>5 μm diameter) sampled was dependent on the niche space available for algal growth and the degree to which soil was exposed to desiccating influences, these factors could be related to the degree of maturity of the sue The numbers of large algal propagules were lowest at sites from which permanent snow cover had recently disappeared and highest at sites with developed soil circles but poorly developed moss and lichen flora Mature sites with diverse and developed moss and lichen flora produced intermediate numbers of algal propagules Propagules of multicellular algae, cyanobacteria and large-celled unicellular algae were found in the air at the end of the growing season of the respective algal groups as the soil surface dried This was the case for Prasiola crispa, Pmnularia borealis , snow algae and filamentous chlorophytes and cyanobacteria Dispersal of unicellular chlorophytes was greatest during the summer period and at sites with developed secondary flora, but also occurred at other sites and in association with small thaw events during winter Cultures were obtained from samples collected whilst an air mass that had originated in South America, deposited material on Signy Island This suggests that algal propagules have the ability to survive long-distance transport and potentially provide mocula for colonization of Antarctica as regional warming continues to expose fresh habitats     

Identification and culturing of cyanobacteria isolated from freshwater bodies of Sri Lanka for biodiesel production

The present study was carried out to investigate cyanobacteria as a potential source for biodiesel production isolated from fresh water bodies of Sri Lanka. Semi mass culturing and mass culturing were carried out to obtain biomass for extracting total lipids. Fatty acid methyl ester (FAME) or biodiesel was produced from extracted lipid by trans-esterification reaction. FAME component was identified using gas chromatography (GC). Atotal of 74 uni-algal cultures were obtained from Biofuel and Bioenergy laboratory of the National Institute of Fundamental Studies (NIFS), Kandy, Sri Lanka. The total lipid content was recorded highest in Oscillatoria sp. (31.9 ± 2.01% of dry biomass) followed by Synechococcus sp. (30.6 ± 2.87%), Croococcidiopsis sp. (22.7 ± 1.36%), Leptolyngbya sp. (21.15 ± 1.99%), Limnothrixsp. (20.73 ± 3.26%), Calothrix sp. (18.15 ± 4.11%) and Nostoc sp. (15.43 ± 3.89%), Cephalothrixsp. (13.95 ± 4.27%), Cephalothrix Komarekiana (13.8 ± 3.56%) and Westiellopsisprolifica (12.80 ± 1.97%). FAME analysis showed cyanobacteria contain Methyl palmitoleate, Linolelaidic acid methyl ester, Cis-8,11,14-eicosatrienoic acid methyl ester, Cis-10-heptadecanoic acid methyl ester, Methyl myristate, Methyl pentadecanoate, Methyl octanoate, Methyl decanoate, Methyl laurate, Methyl tridecanoate, Methyl palmitoleate, Methyl pentadeconoate, Methyl heptadeconoate, Linolaidic acid methyl ester, Methyl erucate, Methyl myristate, Myristoloeic acid, Methyl palmitate, Cis-9-oleic acid methyl ester, Methyl arachidate and Cis-8,11,14-ecosatrieconoic acid methyl ester. The present study revealed that cyanobacteria isolated from Sri Lanka are potential source for biodiesel industry because of their high fatty acid content. Further studies are required to optimize the mass culture conditions to increase thelipid content from cyanobacterial biomass along with the research in the value addition to the remaining biomass.     

Ecology of Pectinatella magnifica and associated algae and cyanobacteria

The freshwater bryozoan species Pectinatella magnifica was found in 6 sandpits and in 19 mostly extensively managed ponds in the Protected Landscape Area and Biosphere Reserve T?eboňsko (Czech Republic) from its first record (in 2003) to 2012. Mean fresh biomass and abundance of P. magnifica colonies were 0.6 ± 1.5 kg m^?2 and 0.7 ± 1.1 colony m^?2 (± SD), respectively, in the shoreline zone during the growing season 2006–2011. The maximum biomass was mostly recorded during the first half of August in all basins. Colonization of further localities was recorded rather than increasing of P. magnifica biomass or abundance in 2012. There were no correlations between water temperature or water transparency and biomass/abundance of P. magnifica during the growing season. P. magnifica colonies preferred to grow on the branches or roots (especially of Salix sp.) to aquatic macrophytes and stones. Most of the water bodies, where this bryozoan species occurred, had lower concentration of total phosphorus in the water when compared with the typical fishponds in the Czech Republic. Inner space of colonies of P. magnifica provided suitable higher trophic level substrate when compared with the water of the sandpits/fishponds especially for green coccal algae. A massive algal colonization was indentified in decomposing colonies at the end of the growing season.     

Colonization and deterioration processes in Roman mortars by cyanobacteria,algae and lichens

The mortars covering some walls of the Roman city of Baelo Claudia (Cadiz, Spain) support an abundant colonization of cyanobacteria, algae and lichens. The distribution of these organisms is closely related to microclimatic parameters. Furthermore, the development, specific composition and biomass of algal cryptoendolithic communities are related to the wall orientation. The effect of these communities on mortar deterioration is discussed.     

Recovery of dairy manure nutrients by benthic freshwater algae

Harnessing solar energy to grow algal biomass on wastewater nutrients could provide a holistic solution to nutrient management problems on dairy farms. The production of algae from a portion of manure nutrients to replace high-protein feed supplements which are often imported (along with considerable nutrients) onto the farm could potentially link consumption and supply of on-farm nutrients. The objective of this research was to assess the ability of benthic freshwater algae to recover nutrients from dairy manure and to evaluate nutrient uptake rates and dry matter/crude protein yields in comparison to a conventional cropping system. Benthic algae growth chambers were operated in semi-batch mode by continuously recycling wastewater and adding manure inputs daily. Using total nitrogen (TN) loading rates of 0.64-1.03 g m(-2) d(-1), the dried algal yields were 5.3-5.5 g m(-2) d(-1). The dried algae contained 1.5-2.1% P and 4.9-7.1% N. At a TN loading rate of 1.03 g m(-2) d(-1), algal biomass contained 7.1% N compared to only 4.9% N at a TN loading rate of 0.64 g m(-2) d(-1). In the best case, algal biomass had a crude protein content of 44%, compared to a typical corn silage protein content of 7%. At a dry matter yield of 5.5 g m(-2) d(-1), this is equivalent to an annual N uptake rate of 1,430 kg ha(-1) yr(-1). Compared to a conventional corn/rye rotation, such benthic algae production rates would require 26% of the land area requirements for equivalent N uptake rates and 23% of the land area requirements on a P uptake basis. Combining conventional cropping systems with an algal treatment system could facilitate more efficient crop production and farm nutrient management, allowing dairy operations to be environmentally sustainable on fewer acres.     

Poly-3-hydroxyalkanoates from marine and freshwater cyanobacteria

Polyesters of (R)-3-hydroxybutanoic and (R)-3-hydroxypentanoic acids have been isolated from Aphanothece species, a freshwater cyanobacteri     

Blue-green algae (cyanobacteria): prospects and perspectives

Summary Photosynthetic, prokaryotic blue-green algae (cyanobacteria) occur in a wide range of natural habitats of diverse ionic composition and as such, represent an important source of biological material for biosolar energy conversion programs using saline water. The gasvacuolate, filamentous Spirulina is grown in seminatural culture in Lake Texcoco, Mexico, as a major source of single-cell protein for animal nutrition. Pilot-scale trials in other areas of the world have also demonstrated the suitability of blue-green algae, including Spirulina, for growth under brackish conditions. The carbohydrate accumulation profiles of blue-green algae differ in isolates from freshwater, marine and hypersaline habitats, with a trend towards sucrose or trehalose accumulation in stenohaline freshwater strains grown in media containing NaCl, while euryhaline and marine forms frequently accumulate glucosylglycerol. Many halotolerant isolates from hypersaline habitats accumulate glycinebetaine in response to osmotic stress. This knowledge may provide scope for future improvement in the N₂ fixation rates of blue-green algae in saline media, using betaine-accumulating N₂-fixing strains in preference to other, saltsensitive isolates.