Spirulina Cultures Research Articles

NUTRIENT RECOVERY AND POLLUTANT REMOVAL FROM PIGGERY WASTEWATER BY SPIRULINA CULTIVATION

Spirulina is noticed for great applications on food supplements, animal feeds, pharmaceutical, cosmetics, biofuel, fertilizer, etc. Spirulina cultures in wastewaters could enhance the feasibility of commodities due to its ability to reduce the cost of biomass production and remove pollutants in wastewaters. This study investigates the effects of wastewater pretreatment using various aeration periods (i.e. from 3 to 7 days), the supplement of bicarbonate and N:P ratios on the growth of Spirulina sp. HH to produce protein-rich biomass. The work showed that Spirulina sp. had the ability to effectively remove ammonium, with the highest efficiencies up to 99.9 %. However, the high concentration of ammonium in wastewater, from 125 mg N/L upward, caused a decline in the growth rate of Spirulina. The growth and remediation potential of Spirulina sp. were in the best condition with the N:P ratio of the medium in the range of 19:1-22:1. This study suggested a procedure to cultivate Spirulina sp. in piggery wastewater and remove pollutants efficiently.

Innovative development of membrane sparger for carbon dioxide supply in microalgae cultures.

The present study was aimed to develop a membrane sparger (MS) integrated into a tubular photobioreactor to promote the increase of the carbon dioxide (CO2 ) fixation by Spirulina sp. LEB 18 cultures. The use of MS for the CO2 supply in Spirulina cultures resulted not only in the increase of DIC concentrations but also in the highest accumulated DIC concentration in the liquid medium (127.4 mg L-1 d-1 ). The highest values of biomass concentration (1.98 g L-1 ), biomass productivity (131.8 mg L-1 d-1 ), carbon in biomass (47.9% w w-1 ), CO2 fixation rate (231.6 mg L-1 d-1 ), and CO2 use efficiency (80.5% w w-1 ) by Spirulina were verified with MS, compared to the culture with conventional sparger for CO2 supply. Spirulina biomass in both culture conditions had high protein contents varying from 64.9 to 69% (w w-1 ). MS can be considered an innovative system for the supply of carbon for the microalgae cultivation and biomass production. Moreover, the use of membrane system might contribute to increased process efficiency with a reduced cost of biomass production.

Biocharacteristics and draft genome sequence of Halomonas hydrothermalis C22, a pyruvate-producing halophilic bacterium isolated from a commercial Spirulina culture in Vietnam.

Halophilic bacteria are receiving increasing attention for industrial chemical production processes due to their unique properties. Herein, an alkaliphilic and halophilic bacterium was isolated from a commercial Spirulina culture at Nghe An province in Vietnam and found to secrete pyruvate. Pyruvate is widely used as a starting material in the industrial biosynthesis of pharmaceuticals, and is employed for production of crop protection agents, polymers, cosmetics, and food additives. Phenotypic and chemotaxonomic characterization, and the 16S rRNA gene sequence homology with Halomonas hydrothermalis strain DSM 15,725 (99.2%) predicted that the strain belongs to the Halomonas genus, thus we named this strain as H. hydrothermalis strain C22. We investigated the biocharacteristics and capacity of strain C22 and determined the draft genome sequence comprising 3,934,166bp with a G + C content of 60.2% encoding 3,668 proteins, 58 tRNAs, 9 rRNAs, and 1 tmRNA. Maximal pyruvate secretion reached 51.1g/l after 84h of cultivation. The results will facilitate future studies on the genetic and metabolic diversity of halophilic bacteria and expand our understanding of important bioprocesses in this microorganism.

Effect of recycling the culture medium on biodiversity and population dynamics of bio-contaminants in Spirulina platensis mass culture systems

Spirulina (Arthrospira) is an important microalga that can generate a variety of commercial products. A semi-continuous mode of cultivation is often employed in microalgal cultivation. The traditional view, however, has been that cultures with recycled medium are more likely to be contaminated by microzooplankton, which is regarded as one of the critical problems in mass algal cultivation. In this study, the relationship between the population dynamics of contaminants and the medium conditions was investigated in Spirulina cultures. Spirulina platensis was cultivated in three groups of raceway ponds: one with fresh culture medium, one with medium that had been recycled for a month, and the third with medium recycled for six months. The results showed that totally 13 species of microzooplankton were observed by light microscopy, and 42 operational taxonomic units (OTUs) of prokaryotic contaminants were detected using amplicon sequencing. Out of all the contaminants, Brachionus plicatilis and Euplaesiobystra hypersalinica were observed to be the most harmful species in Spirulina cultures, while Proteobacteria were the most commonly found non-Cyanobacteria OTUs. On the initial day, more species of microzooplankton were introduced to the cultures that had recycled medium (9 species) than to those that had fresh medium (5 species). By the end of the cultivation, the algal biomass in the fresh medium group was the highest (2.8 g L−1), being almost 5 times higher than in the other two groups (around 0.50 g L−1). Our results proved that Spirulina can grow the best with fresh medium and that the more the culture medium is recycled, the stronger the inhibition on the growth of microalgae and microzooplankton. In order to improve large-scale Spirulina production, it is necessary to both subject the recycled medium to appropriate treatment to reduce the presence of harmful predators and to find effective ways to control contaminants.

Electrogenic and biomass production capabilities of a Microalgae–Microbial fuel cell (MMFC) system using tapioca wastewater and Spirulina platensis for COD reduction

ABSTRACT Tapioca is a starch extracted from cassava and is one of the most important products of the secondary food industry in developing countries such as Indonesia. However, the processing of cassava to extract tapioca generates nutrient-rich wastewater. In this paper, the bioelectricity and biomass production from microalgae Spirulina platensis within a hybrid Microalgae-Microbial fuel cell to reduce the chemical oxygen demand in wastewater from home-made tapioca industry is investigated. Native microbes in tapioca wastewater are used as inoculum in the anode chamber to generate electrons, while Spirulina culture in cathode chamber produces oxygen for the Oxygen Reduction Reaction. Cheap graphite rods, singlet or doubled, are used as electrodes and the influence of dark/light period is also studied. The experimental results show that the device generates electricity up to 14.47 ± 0.7 mW·m−2 when doubled graphite rods are adopted, the membrane surface area is 2.85 cm2, and dark/light cycle is 0:24. The chemical oxygen demand removal is 67% in this configuration, while the average productivity of Spirulina is approximately 55.38 ± 6.39 mg·L−1·day−1, with average growth rate constant of 0.172 ± 0.015 day−1. The proposed systems for tapioca wastewater treatment provides an encouraging way to reduce treatment costs, to generate renewable bioelectricity and to produce useful microalgae biomass.

Brackish Groundwater from Brazilian Backlands in Spirulina Cultures: Potential of Carbohydrate and Polyunsaturated Fatty Acid Production.

The composition of brackish groundwater from Brazilian backlands contains important elements necessary for metabolism in microalgae. This study evaluated the use of 100% brackish groundwater with different amounts of Zarrouk nutrients for Spirulina sp. LEB 18 cultivation. The growth parameters and biomass composition, including the concentrations of proteins, carbohydrates, ash, lipids, and fatty acids, were evaluated. The best growth parameter results were obtained in the assay using 100% brackish groundwater and only 25% of Zarrouk nutrients, which were equal to those obtained for the control culture. The concentrations of carbohydrates and polyunsaturated fatty acids were increased by as much as 4- and 3.3-fold, respectively, when brackish groundwater was used in the cultures. The lipid profile demonstrated that the biomass had the potential for use in biodiesel production. The use of brackish groundwater is a sustainable, economical way to obtain high-quality biomass for different applications during Spirulina sp. LEB 18 cultivation.

Increasing productivity of Spirulina platensis in photobioreactors using artificial neural network modeling.

Although production of microalgae in open ponds is conventionally practiced due to its economy, exposure of the algae to uncontrollable elements impedes achievement of quality and it is desirable to develop closed reactor cultivation methods for the production of high value products. Nevertheless, there are several constraints which affect growth of in closed reactors, some of which this study aims to address for the production of Spirulina. Periodic introduction of fresh medium resulted in increased trichome numbers and improved algal growth compared to growth in medium that was older than 4 weeks in 20 L polycarbonate bottles. Mixing of the cultures by bubbling air and use of draft tube reduced the damage to the growing cells and permitted increased growth. However, there was better growth in inclined cylindrical reactors mixed with bubbling air. The oxygen production rates were very similar irrespective differences in the maintained cultures densities. The uniformity in oxygen production rate suggested a tendency towards homeostasis in Spirulina cultures. The frequency of biomass harvest on the productivity of Spirulina showed that maintenance of moderate culture density between 0.16 and 0.32 g/L resulted in about 14% more productivity than maintaining the cell density between 0.16 and 0.53 g/L or 48% more than by daily harvest above 0.16 g/L. An artificial neural network based predictive model was developed, and the variables useful for predicting biomass output were identified. The model could predict the growth of Spirulina up to 3 days in advance with a coefficient of determination >0.94.

Peningkatan Kualitas Ikan Koi (Cyprinus carpio) di Kelompok PBC Fish Farm di Kecamatan Cisaat, Sukabumi

Various ornamental fish, such as koi and comet is a mainstay commodity from Nagrak Village, Cisaat District, Sukabumi Regency, West Java. The ornamental fish farmers in this village have been grouped in the form of pokdakan called “Pokdakan PBC Fish Farm”, which is chaired by Ikral Panutan. The main problem faced by members of this group is the color of the ornamental fish which still in low grade in quality. The purpose of this activity was to improve the quality of koi ornamental fish by using additional powder feed spirulina so that it can give added value to the production of ornamental fish produced. Community empowerment activities have been conducted for 4 months from July to October 2016. Steps of implementation include: 1) Socialization and initiation stage; 2) Training about fish culture management, spirulina culture method and feeding method using discussion method and demonstration plots; and 3) Evaluation and monitoring phase. The results obtained are generally these activities get the response and good results from the extension participants, as evidenced by the ability of farmers in cultured spirulina henceforth be applied as a mixture of fish feed can result in improved color quality of koi. Use of spirulina powder feed additional material on Cyprinus carpio of PBC Fish Farm proven to improve color quality, and provide value-added economy by 50–100 with the selling price ranging from IDR 3.000, per head to IDR 4.500–6.000 per tail.

Comparative study on the growth performance of Spirulina platensis on modifying culture media

India faces a severe challenge to ensure adequate nutrition for children and women. Chronic child nutrition deficiency is more prevalent in Madhya Pradesh state of India. Spirulina, multicellular and filamentous cyanobacterium are considered an absolute food supplement to combat malnutrition in Asian and African countries. Spirulina cultivation requires sufficient aeration, agitation and proper light intensity for enhanced biomass yield, cell productivity, specific growth rate, and protein content. This paper presents a novel experimental approach to maximize biomass yield, minimize evaporation rate and respiration losses in a laboratory scale closed reactor and open pond system. Lab scale open pond and closed reactor system were designed for spirulina cultivation under dry climatic conditions at Bhopal, India. Zarrouk media was used as standard and modified organic media was prepared by changing the nitrogen source. Temperature and other input parameters were maintained. Aeration was done manually in an open pond, and the air pump was used in the case of a closed reactor system. Biomass yield obtained from an open pond system was 11.34 g/l, and 12.28 g/l in the closed reactor system. Doubling time was also less in the closed reactor in comparison with the open pond system. Urea seems to be a promising alternative source of low-cost nitrogen for Spirulina cultures. From the experimental results, it is concluded that modified organic media and closed reactor system could be used for better biomass yield.

Large-scale cultivation of Spirulina in a floating horizontal photobioreactor without aeration or an agitation device.

A low-cost floating photobioreactor (PBR) without the use of aeration and/or an agitation device, in which carbon was supplied in the form of bicarbonate and only wave energy was utilized for mixing, was developed in our previous study. Scaling up is a common challenge in the practical application of PBRs and has not yet been demonstrated for this new design. To fill this gap, cultivation of Spirulina platensis was conducted in this study. The results demonstrated that S. platensis had the highest productivity at 0.3molL-1 sodium bicarbonate, but the highest carbon utilization (104 ± 2.6%) was obtained at 0.1molL-1. Culture of Spirulina aerated with pure oxygen resulted in only minor inhibition of growth, indicating that its productivity will not be significantly reduced even if dissolved oxygen is accumulated to a high level due to intermittent mixing resulting from the use of wave energy. In cultivation using a floating horizontal photobioreactor at the 1.0m2 scale, the highest biomass concentration of 2.24 ± 0.05gL-1 was obtained with a culture depth of 5.0cm and the highest biomass productivity of 18.9gm-2day-1 was obtained with a depth of 10.0cm. This PBR was scaled up to 10m2 (1000L) with few challenges; biomass concentration and productivity during ocean testing were little different than those at the 1.0m2 (100L) scale. However, the larger PBR had an apparent carbon utilization efficiency of 45.0 ± 2.8%, significantly higher than the 39.4±0.9% obtained at the 1m2 scale. These results verified the ease of scaling up floating horizontal photobioreactors and showed their great potential in commercial applications.

IMPROVING NUTRIENT FORMULATION FOR CULTURE OF (Spirulina platensis) TO REPLACE THE TRADITIONAL ZARROUK IN TERMS OF ECONOMIC ASPECT IN TRA VINH

This study aims to find an improved nutrient formulation for culturing spirulina (Spirulina platensis) from the traditional formulation (Zarrouk). Experiments are applied in outside condition with simple transparent plastic cover combined with black camo netting. The first experiment tested the efficiency of 25% Zarrouk+ iodine formulation and the second experiment was applied fully Zarrourk formulation. The result shows that the first experiment reached 37.42 ± 3.881 cells/ml with total biomass approaches 643.3 ± 80.2 (g /0.5 m3). The second experiment reachs 43.422 ± 3.845 cells/ml with average biomass of ∼ 791.7 ± 52 (g/0,5 m3) with (P-value < 0,05). In conclusion, the improved nutrient formulation with original 25% Zarrouk adding iodine which contributes to improve Spirulina culture effectiveness in economic aspect which decreases expenses up to 75% as compared to Zarrourk

Biodiversity and distribution of microzooplankton in Spirulina (Arthrospira) platensis mass cultures throughout China

Spirulina (Arthrospira) platensis is the most commonly produced microalgae for commercial applications, such as nutraceuticals and feed. While crop productivity of commercial Spirulina farms is often compromised by grazers and contaminating microzooplanktons, the biodiversity and identity of the most harmful microzooplanktons in Spirulina farms have not been extensively studied. As China is the number one producer of Spirulina in the world, comprehensive information on the biodiversity and identity of microzooplanktons in Spirulina farms is essential for the long-term commercial viability of these farms. Therefore, we determined the biodiversity and identity of the major microzooplanktons that are present in eight commercial Spirulina cultivation sites throughout China. Furthermore, we identified the major grazers that appear to directly affect the productivity of Spirulina cultures. Among twenty-three species that include 2 flagellates, 2 amoebae, 15 ciliates, and 4 rotifers, Brachionus plicatilis, Frontonia sp. and one unknown Heterolobosean amoeba appeared to be the most harmful to Spirulina due to their high density and ability to graze Spirulina. The similarity of the biodiversity and abundance of the microzooplankton was >80% among two out of eight mass cultivation sites (C and D), while the remaining cultivation sites exhibited their own unique microzooplankton biodiversity characteristics. Redundancy analysis (RDA) showed that there was a positive relationship between harmful species of Brachionus plicatilis and salinity, while the other two harmful species of Heterolobosean amoeba and Frontonia sp. had a positive relationship with oxidation-reduction potential (ORP). As this is the first report to identify the major harmful microzooplankton species in commercial Spirulina farms, our study not only provides a theoretical basis for the relationship between environmental factors and biodiversity of harmful grazers but also lays a scientific foundation for developing effective monitoring and management strategies for commercial Spirulina farms.

Magnetic field action on outdoor and indoor cultures of Spirulina: Evaluation of growth, medium consumption and protein profile

This study aimed at evaluating whether a magnetic field (MF) affects the growth of Spirulina sp. when applied to it at different exposure times in indoor and outdoor culture systems. The effects of MF on chlorophyll content, medium consumption and protein profile were also investigated. In raceway tanks, a 25 mT MF was applied for 24 h or for 1 h d−1. MF for 24 h to outdoor assays increased biomass concentration and chlorophyll-a content besides altering the protein profile. Outdoor Spirulina growth was higher (∼3.65 g L−1) than the growth found in indoor assays (∼1.80 g L−1), while nitrogen and phosphorus consumption was not enhanced by the application of MF. This is the first study that investigated the influence of MF on outdoor microalga assays, and the results showed that MF affected the metabolism of Spirulina cultured in raceways, especially when it was grown outdoors in uncontrolled environmental conditions.

Ammonium bicarbonate supplementation as carbon source in alkaliphilicSpirulinamass culture

Cyanobacterium Spirulina (Arthrospira) platensis is a commercial product with high content of protein and other nutritional elements, serving as a source of nutrients for food, feed and pharmaceutical industry. Generally, CO2 gas bubbling method is a common method to supply carbon source for algae culture. However, in commercial situation where the CO2 supply is limited, alternative bicarbonate could be utilized as a substitute carbon source in Spirulina cultivation. In this study, the optimum culture method of ammonium bicarbonate supplementation in open raceway pond as carbon source was firstly investigated to avoid the inhibition effect of ammonium bicarbonate. The optimal conditions estimated by experimental results for S. platensis cultivation were set as following: (1) the addition of ammonium bicarbonate at each time must be <2.0 mmol L−1; (2) the addition rate of ammonium bicarbonate is in the range of 10–20 g m−2 day−1. Then, S. platensis were cultured in eight 800 m2 raceway ponds with fed-batch addition of ammonium bicarbonate combined with sodium bicarbonate as carbon source. The results illustrated that ammonium bicarbonate addition not only did not show any adverse impact on productivity, chlorophyll and carotenoid content of S. platensis, but also significantly increased the protein content of S. platensis. With ammonium bicarbonate supplementation as carbon source in alkaliphilic Spirulina mass culture, the carbon utilization efficiency was dramatically increased to approximately 70% from 38.89%, and the carbon cost was reduced by approximately 57%. Therefore, ammonium bicarbonate can be applied as supplement of carbon source for alkaliphilic Spirulina culture.

Effect of cilofungin on the growth and metabolite production in spirulinasp and chlorellasp

A novel strategy of using an antifungal cilofungin to alter the algal metabolics for increased production of biomass, fat, protein and other metabolites were inferred. The effect of varying concentrations of cilofungin (0.02% to 0.1%) on unialgal cultures of Spirulina sp. and Chlorella sp. isolated from ennore estuary, Chennai, an highly polluted coastal ecosystem in India was investigated. Various parameters like cellular growth, dry mass, carbohydrates, proteins, fatty acids, chlorophyll and carotenoids were assessed with respect to time. At a given cilofungin concentration of 0.08% in Spirulina sp and 0.06% in Chlorella sp, an increase in protein content from 421mg/g to 655mg/g and 430mg/g to 646 mg/g of biomass, an increase in fat content from 57mg/g to 74 mg/g and 75 mg/g to 90mg/g of biomass was obtained in comparison to their mother cultures with a simultaneous increase in their biomass concentration from 1.09g/l to 1.5g/l and 1 g/l to 1.23g/l respectively, whereas the carbohydrates were gradually decreased in cilofungin treated cultures. This study thus analyse the effect of cilofungin in algae, inhibiting the glucan production and inducing the alternate metabolic pathways in Spirulina sp and Chlorella sp. for lipid and protein accumulation.

Optimization of Spirulina sp. Drying in Heat Pump: Effects on the Physicochemical Properties and Color Parameters

The aim of this work was to optimize the drying operation of Spirulina sp. using the heat pump to dehumidify the air. An experimental design using the drying air temperature (30, 40 and 50C) and the initial sample thickness (1, 3 and 5 mm) was performed. The responses were the physicochemical properties and the color parameters of the dried microalgae. The air temperature presented the highest effect on the phycocyanin content, while the sample thickness showed the highest influence on the other responses. The optimal operating conditions for the heat pump drying of Spirulina sp. were at air drying temperature of 50C and sample thickness of 5 mm. The phycocyanin content, total antioxidant activity and color difference were found to be 19.60 mg/g, 52.6% and 5.71, respectively. Thermograms (differential scanning calorimetry) showed that under these conditions, the product showed the highest thermal stability. Practical Applications The culture of Spirulina sp. is attractive for various commercial purposes, such as nutritional supplement for humans and animals and supply of active metabolites in the pharmaceutical and cosmetic industry. The conventional tray drying is a traditional method that is used in the microalgae drying. However, the heat pump drying enables operation in lower temperatures than the traditionally used in convective hot air drying. This operation occurs in moderate conditions of temperature and humidity due to air dehumidification, leading to retention of bioactive compounds in products that are heat sensitive. Therefore, the use of heat pump dryer for the production of dried Spirulina should be promising to preserve its phytochemicals and physical characteristics. The benefits of heat pump drying have been shown in different studies in the literature, but there are no reports about its use in Spirulina drying and its influence on the physicochemical and functional characteristics.

Automated System for Identifying and Recognizing Rotifer Contamination in Spirulina

The blue green microalgae Spirulina platensis is an important source of nutrients. An important obstacle for the ­production­of­Spirulina­is­Rotifer.­ In­ this­paper­we­present­a­method­ for­automated­identification­and­recognition­of rotifer contamination in Spirulina using image processing techniques. Getting the expert’s advice is an essential one to improve the production. Our primary objective is to provide high nutrients Spirulina free from contaminations and secondary objective is to solve the quality issue by identifying rotifer contaminations at the earliest and giving suggestions through­the­mobile­phones.­Using­microscopic­examination­for­identifying­rotifier­in­live­culture­is­time­consuming­and manmade process. There is a chance for man made error and our new technique is machine made and the errors to be minimized.­Existing­system­need­qualified­persons­for­operation­and­our­proposed­system­can­be­operated­by­anyone. We examine lab scale Spirulina culture through both existing and new techniques for recognizing the rotifer. Our proposed tool for identifying contaminations at beginning stage is easy to eradicate the contaminations from live culture. It will be helpful to biologist to take necessary actions against contaminations of the same before further multiplications of contaminations. According to the Survey of Sun food Super Food, in 2020 the expected world wide Spirulina production is about 220 thousand tons. Hence Spirulina can be a solution for solving the world nutrition problems due to its very high­growth­rate­and­high­nutritional­value.­Our­research-automatic­identification­of­contamination­in­algae­through­the processing­of­mobile­phone­images­is­an­easiest­way­for­improving­and­evaluating­the­growth­of­Spirulina­for­effective cultivation of algae. Keywords: Automatic Detection and Contamination, Image Processing, Recognition, Rotifer, Spirulina

Bituminous coal and sodium hydroxide-pretreated seawater stimulates Spirulina (Arthrospira) maxima growth with decreased production costs

Spirulina is a photosynthetic cyanobacterium rich in protein, polyunsaturated fatty acids, minerals and vitamins. Spirulina spp. are produced in fresh water, although freshwater shortages and the high-cost of feed stock carbon limit Spirulina production. Thus, use of seawater with low-cost carbon should be evaluated. Conversely, Ca 2 + and Mg 2 + of natural seawater (NSW) cause milky turbidity and nutrient precipitation when used in Spirulina culture medium. Here, NSW was pretreated with bituminous coal and NaOH to sediment Ca 2 + and Mg 2 + and obtain total organic carbon (TOC)-enriched pretreated seawater supernatant (PSWS), which was used to formulate Spirulina maxima culture medium. Pretreatment of NSW with bituminous coal and NaOH showed Ca 2 + and Mg 2 + precipitation rates of 32.52% and 99.91%, respectively, while TOC increased 6.97-fold in PSWS compared to NSW. The PSWS was 90–93% of NSW by volume, excluding sediment. The dry biomass production was 1.55 and 1.57 g L − 1 and the chlorophyll a content was 13.75 and 17.90 mg L − 1 in SOT and formulated AKSM-2-1 media, respectively. The maximum specific growth rate (μ max day − 1 ) and biomass productivity of S. maxima were 0.283 and 0.284 day − 1 and 1.97 and 2.00 g L − 1 day − 1 in SOT and formulated media, respectively. The biochemical composition and phycocyanin content were similar in the biomass of both media. Biomass production costs were ca. threefold lower in formulated medium than SOT medium. Therefore, S. maxima can be produced at lower costs using NSW following our method. • Pretreatment of natural seawater (NSW) with bituminous coal and NaOH made adequately sediment of Ca 2 + and Mg 2 + . • Total organic carbon increased ~ 7 times in pretreated seawater supernatant (PSWS) than NSW. • Use of PSWS resolved K 2 HPO 4 solubility problem in seawater Spirulina maxima culture medium. • Biomass production and biomass quality were same in formulated and SOT media. • Biomass production cost ~ 3 times lower in formulated medium than that of conventional medium.

Aplicacion de estrategias nutricionales y su efecto en el crecimiento en el cultivo continuo de Spirulina (Arthrospira platensis)

A continuous culture of Spirulina (Arthrospira platensis) was performed for 78 in a tubular photobioreactor of 300 L volume. During this period there was growth in biomass and crop response to the strategy of adding the nutrient medium. Using as a basis the modified Zarrouk medium, three nutritive combinations were elaborated: initial medium (MI), growth medium (SA1+SA2) and maintenance medium (SB1+SB2) for different crop stages. The media delivery is affected gradually and in accordance with requirements of growing biomass (dry weight) daily cultivation. The initial crop biomass was 2.0 g L -1 , on day 20 of culture was made the first partial harvest (50%) starting a new stage of the crop with an initial biomass of 1.7 g L -1, 20 days after a second crop was partially culture initiating a third culture step with a biomass of

Evaluation of growth yield of Spirulina (Arthrospira) sp. in photoautotrophic, heterotrophic and mixotrophic cultures

In microbial cultures, both cellular growth rate and yield (defined as the degree of substrate conversion into the biomass) are important. Although effect of culture conditions on growth kinetics has been well documented for various microbial strains, there is almost no literature concerning the effect of environmental conditions on growth equilibrium, expressed as biomass yield coefficients from substrate. The present paper discusses the effect of culture conditions: irradiance (physical substrate) and glucose concentration (chemical substrate) on biomass yield coefficients from two chemical substrates: glucose and nitrate-nitrogen in photoautotrophic, heterotrophic and mixotrophic culture of blue-green alga Spirulina (Arthrospira) sp. The efficiency of substrates incorporation into the biomass can be precisely determined only if the elemental composition of the biomass is known. The experimental results showed that culture conditions had a substantial influence on biomass yield coefficients (biomass yield from glucose and nitrate-nitrogen). It was found that, the increase of irradiance favoured increase of biomass yield coefficient from both, glucose and nitrate-nitrogen. However, in the case of yield from nitrogen in mixotrophic culture, the effect was opposite. The effect of glucose concentration was different: the higher the initial glucose concentration, the lower the biomass yield coefficients from chemical substrates.