Analysis of the biomass quality and photosynthetic efficiency of a nitrogen-fixing cyanobacterium grown outdoors with two agitation systems (original) (raw)
Related papers
Applied and environmental microbiology, 1979
Thermophilic, nitrogen-fixing, blue-green algae (cyanobacteria) were investigated for use in biophotolysis. Three strains of Mastigocladus laminosus were tested and were found to be equally effective in biophotolysis as judged by nitrogenase activity. The alga, M. laminosus NZ-86-m, which was chosen for further study, grew well in the temperature range from 35 to 50 degrees C, with optimum growth at 45 degrees C, at which temperature acetylene reduction activity was also greatest. The maximum tolerable temperature was 55 degrees C. Acetylene reduction activity was saturated at a light intensity of 1 x 10 ergs cm s. Atmospheric oxygen tension was found to be slightly inhibitory to acetylene reduction of both slowly growing and exponentially growing cultures. Nonsterile continuous cultures, which were conducted to test problems of culture maintenance, could be operated for 2 months without any significant decrease in nitrogenase activity or contamination by other algae. Nitrogen-starv...
Outdoor cultivation of a nitrogen-fixing marine cyanobacterium, Anabaena sp. ATCC 33047
Biomolecular Engineering, 2003
Optimization of conditions for outdoor production of the nitrogen-fixing cyanobacterium Anabaena sp. ATCC 33047 has been pursued. In open ponds operated under semi-continuous regime biomass productivity values achieved ranged from 9 g (dry weight) m (2 per day, in winter, to over 20 g m (2 per day, in summer, provided that key operation parameters, including cell density, were optimized. Under these conditions the efficiency of solar energy conversion by the cells was fairly constant throughout the year, with photosynthetic efficiency values higher than 2%. The cyanobacterial biomass was rich in high-value phycobiliproteins, namely allophycocyanin and phycocyanin, for which open cultures of marine Anabaena represent a most interesting production system. The performance of Anabaena cultures operated under continuous regime in a closed tubular reactor has also been assessed outdoors, in winter. Biomass productivity values similar to those obtained in the ponds have been recorded for the closed system. Additionally, under these conditions, the cells excreted to the medium large amounts of a previously characterized exopolysaccharide, at production rates as high as 35 g m (2 per day (1.4 g l (1 per day). Properly operated closed cultures of this strain of Anabaena appear most suitable for outdoor mass production of valuable extracellular polysaccharides. #
Applied Energy, 2011
Recently research interest has focused on the production of biofuel from microalgae. Microalgae are photosynthetic microorganisms that grow utilizing solar energy, nevertheless, the quantities of fertilizers that should be used for their production are enormous. One alternative to the use of synthetic fertilizers is to employ wastes and wastewaters (W&WWs), especially from the agro-industrial sector which are rich in inorganic pollutants such as nitrogen and phosphorus, which can be recovered. Simultaneously with the cultivation of microalgae using wastes and wastewaters for biomass production, treatment of the wastes and wastewaters occur through removal of the pollutants. Filamentous cyanobacteria appear to be suitable candidates for cultivation in wastes and wastewaters because they produce biomass in satisfactory quantity and can be harvested relatively easily due to their size and structure. In addition their biomass composition can be manipulated by several environmental and operational factors in order to produce biomass with concrete characteristics. Herein we review the factors that affect the biomass composition of cyanobacteria and present several studies that discuss the culture of filamentous cyanobacteria in agro-industrial wastes and wastewaters, with special emphasis on Spirulina.
Recently research interest has focused on the production of biofuel from microalgae. Microalgae are photosynthetic microorganisms that grow utilizing solar energy, nevertheless, the quantities of fertilizers that should be used for their production are enormous. One alternative to the use of synthetic fertilizers is to employ wastes and wastewaters (W&WWs), especially from the agro-industrial sector which are rich in inorganic pollutants such as nitrogen and phosphorus, which can be recovered. Simultaneously with the cultivation of microalgae using wastes and wastewaters for biomass production, treatment of the wastes and wastewaters occur through removal of the pollutants. Filamentous cyanobacteria appear to be suitable candidates for cultivation in wastes and wastewaters because they produce biomass in satisfactory quantity and can be harvested relatively easily due to their size and structure. In addition their biomass composition can be manipulated by several environmental and operational factors in order to produce biomass with concrete characteristics. Herein we review the factors that affect the biomass composition of cyanobacteria and present several studies that discuss the culture of filamentous cyanobacteria in agro-industrial wastes and wastewaters, with special emphasis on Spirulina.
Journal of Applied Phycology, 1994
The performance of Nodularia harveyana, a N 2 -fixing cyanobacterium isolated from seawater, has been studied outdoors in two different culture systems: open pond (OP) and tubular photobioreactor (TPR). The productivity in both devices was influenced by areal density. The maximum yield obtained was 12.0 g (d.wt) m -2 day-in OP and 14.0 g (d.wt) m -2 day-' in TPR in August, corresponding to the highest solar radiation received. In a month-long experiment with the cyanobacterium cultivated in TPR at high circulation speed, a net increase in productivity was obtained over that at low circulation speed. The influence of temperature on the productivity of the cultures grown in open ponds and tubular photobioreactors has been investigated. The higher productivity obtained in TPR compared to OP was attributed to its better controlled temperature conditions. In outdoor culture the maximum nitrogenase activity did not coincide with the maximum light intensity, but occurred in early afternoon. The amount of carbohydrate accumulated during the day probably influenced the rate of dark nitrogenase activity and its duration in the night.
Nitrogen derived from Combined Algal Processing supports algae cultivation for biofuels
Algal Research, 2020
Algae biomass, a biofuel feedstock with potential to reduce global CO 2 emissions, is currently too expensive Nitrogen, a significant input and life cycle cost, requires research on recycling and additional sources to reduce costs. Integral to nitrogen recycling is the knowledge of actual nitrogen requirements in outdoor ponds, thus data from the Unified Field Studies of the Algae Testbed Public-Private Partnership was analyzed. The data showed that Nannochloropsis oceanica used 14-24 mg/L NH 4 + per harvest cycle for robust growth. Nitrogen recycled directly from the algae conversion process will likely be the primary source of nitrogen for algae cultivation. Harvested algae can be fractionated via Combined Algal Processing (CAP), where algae are pretreated, fermented, and the fuel feedstocks (e. g. ethanol, lipids) are removed leaving a nitrogen rich slurry. Chlorella vulgaris grew robustly in nitrogen-free media supplemented with CAP residues through 4 harvest cycles with no inhibition. The amount of nitrogen as free ammonium available for recycling directly without further processing was insufficient (~4% of total needed), thus the nitrogen fixing bacteria, Azotobacter vinelandii, was investigated as a means for increasing ammonium concentration in CAP residues. This organism was shown to be proficient at growth on sugars liberated from algae biomass during pretreatment and sustained algae growth using A. vinelandii supernatants was also demonstrated. Using Azotobacter to increase ammonium concentrations on-site using an inexpensive biological process to generate the necessary ammonium for outdoor algae cultivation improves sustainability of algae biofuels by avoiding the energy intensive steps of typical ammonium production and transport. These results show that byproducts of algae conversion begin to close nitrogen demand and, with further supplementation by diazotrophic bacteria or protein hydrolysis, may completely replace current energyintensive and costly industrial nitrogen sources offering a path to increased economic feasibility and improved life cycle analysis of algae-based biofuels.
Evergreen, 2019
Photobioreactor (PBr) is a system that usually used for producing high amount of biomass. This system was designed for supplying multiple factor that providing a good biological condition for growth of the microalgae contained in the system. This research used Synechococcus sp. HS-9, an indigenous cyanobacteria isolated from Rawa Danau hot spring, Banten. This strain was selected because their ability to adapt and reproduce. Synechococcus sp. HS-9 was inoculated into two units of tubular photobioreactor (tPBr) along with NPK medium and then observed using turbidimeter. This strain of cyanobacteria is grown up to 4.44 x 10 6 cells/mL (tPBr-1) and 4.29 x 10 6 cells/mL (tPBr-2) (cell number) or 56.5 NTU (tPBr-1) and 55.9 NTU (turbidity) after eleven days. The results showed that combination of NPK media, tPBr system, and Synechococcus sp. HS-9 are producing potential biomass for biofuel feedstock. This research also proved that use of NPK media as growth medium are promising, because of the good efficiency of cost production.
Eco-physiological responses of nitrogen-fixing cyanobacteria to light
Hydrobiologia, 2010
The eco-physiological responses of three nitrogen-fixing cyanobacteria (N-fixing cyanobacteria), Aphanizomenon gracile, Anabaena minderi, and Ana. torques-reginae, to light were assessed under nutrient saturation. The N-fixing cyanobacteria were isolated into monocultures from a natural bloom in a shallow colored lake and their growth irradiance parameters and pigment composition were assessed. The different ecological traits related to light use (l max , a, I k) suggest that these N-fixing cyanobacteria are well adapted to low light conditions at sufficient nutrients, yet interspecific differences were observed. Aphanizomenon gracile and Anabaena minderi had high relative growth rates at low irradiances (ca. 70% of those in high light), low half saturation constant for light-limited growth (I k \ 9.09 lmol photon m-2 s-1) and high efficiency (a \ 0.11 day-1 lmol photon-1 m 2 s). Conversely, Ana. torques-reginae showed poorer light competitiveness: low relative growth rates at low irradiances (ca. 40% of those in high light), low a (0.009 day-1 lmol photon-1 m 2 s) and higher I k (35.5 lmol photon m-2 s-1). Final densities in Aphanizomenon gracile and Anabaena minderi reached bloom densities at irradiances above 30 lmol photon m-2 s-1 with different hierarchy depending on irradiance, whereas Ana. torques-reginae never achieved bloom densities. All species had very low densities at irradiances B17 lmol photon m-2 s-1 , thus no N-fixing blooms would be expected at these irradiances. Also, under prolonged darkness and at lowest irradiance (0 and 3 lmol photon m-2 s-1) akinetes were degraded, suggesting that in ecosystems with permanently dark sediments, the prevalence of N-fixing cyanobacteria should not be favored. All species displayed peaks of phycocyanin, but no phycoeritrin, probably due to the prevailing red light in the ecosystem from which they were isolated. Keywords Nitrogen fixing cyanobacteria Á Light Á Growth-irradiance Á Eco-physiological traits Á Akinetes Light levels that phytoplankton receive may oscillate between darkness in the aphotic zone to irradiances higher than 1,500 lmol photon m-2 s-1 in the surface.
Determining the optimal nitrogen source for large-scale cultivation of filamentous cyanobacteria
Journal of Applied Phycology, 2016
As the world's population continues to increase and the adverse effects of anthropomorphic CO 2 intensify, it is becoming increasingly important to develop biofuels and chemicals from sustainable resources. Filamentous cyanobacteria, including Anabaena sp. PCC 7120, have emerged as a promising source of renewable chemicals and biofuels due to their minimal nutrient requirements and the relative ease with which they can be genetically engineered to produce a diversity of products. This study evaluated the effects of several nitrogen sources on the growth of Anabaena sp. PCC 7120, and then performed an environmental comparative study on a theoretical large-scale production process to down-select to the best nitrogen source. Sodium nitrate and ammonium chloride yielded 65 % more growth compared to the other nitrogen sources evaluated. Ammonium chloride yielded marginal savings of US$22,318 annually, compared to sodium nitrate over a 27-year lifespan of a proposed chemical production facility utilizing filamentous cyanobacteria. Sodium nitrate had substantially greater negative impacts in every environmental category compared to ammonium chloride. For example, sodium nitrate had a ∼threefold greater negative impact in human health, ecosystem quality, and resources categories. Thus, we concluded that ammonium chloride is the preferred nitrogen source in large-scale processes involving filamentous cyanobacteria.