Physiological and biochemical traits, antioxidant compounds and some physico-chemical factors of Spirulina platensis cultivation as influenced by Moringa oleifera leaves extract culture medium enriched with sodium bicarbonate and kanwa (2025)

Production and nutritive value of Spirulina platensis in reduced cost media

The Egyptian Journal of Aquatic Research, 2012

This study aimed to provide a cost effective medium to large scale production of Spirulina platensis. This intention was implemented by substituting all the nutrients present in Zarrouk's medium (SM) with cheaper and locally available commercial fertilizers and chemicals. The Reduced Cost medium contained single super phosphate (SSP), commercial sodium bicarbonate, Muriate of potash (MOP) and crude sea-salt, (Syahat salt). Four grades of nitrogen concentrations representing 10%, 20%, 30% and 40% of SM nitrogen concentration (29.42 mM-N) were taken from ammonium nitrate (Treatments 1-4) or urea (Treatments 5-8) respectively, for testing. The alga was grown for 33 days at 30 ± 2°C, pH 9, 30 lEm 2 s À1 irradiance. The growth characteristics (maximum biomass X m , cell productivity P x , specific growth rate l m and chlorophyll concentration), and biochemical composition (proteins, carbohydrates and lipids) of the alga grown in these media were compared with that cultivated in SM. Significant differences in the growth parameters and biochemical composition were observed for the different nitrogen sources and concentrations. The results revealed that S. platensis could utilize ammonium nitrate most efficiently and that growth was enhanced with increasing the concentrations of ammonium nitrate giving maximum biomass at 0.353 g/L (Treatment 3). Further increasing the concentration limited growth. The growth parameters in urea showed a significant decrease associated with increasing urea concentrations. The maximum biomass, chlorophyll and protein yield (0.813 ± 0.018 mg/L, 0.0685 ± 0.0024 lg/L and 52.62%, respectively) were recorded using Treatment 3 which was comparable with that of SM (0.

Use of liquid rice starch as a source of carbon for growth of Spirulina platensis

Journal of Fisheries and Life Science, 2018

A study was conducted to examine the culture and growth performance of S. platensis in three different concentrations (25%, 50% and 100%) of digested liquid rice starch media (DLRSM) with 0.2 g/L urea and Kosaric medium (KM) as control for a period of three months from March to May 2018. Each experiment was done in triplicates for a period of 14 days. The growth rate of S. platensis was found to vary with different concentrations of the medium. The cell weight of S. platensis was attained to highest 12.42 mg/L (dry weight) in KM followed by 11.26 mg/L, 8.35 mg/L and 9.11 mg/L in 25%, 50% and 100% of DLRSM, respectively on the 10th day of culture period. Similar trend also observed in case of chlorophyll a content of S. platensis. The proximate composition of rice starch was analyzed. The percentage of moisture, protein, lipid, ash, crude fiber and nitrogen free extract (NFE) were95.1, 0.2616, 0.1055, 0.1097, 0.1468 and 3.9669, respectively on the basis of moisture (%) and 4.59, 5.70, 2.30, 2.39, 3.20 and 86.41, respectively on the basis of dry matter (%). The results on the growth performance showed that the growth of S. platensis was significantly (P<0.01) higher when grown in 25% concentration of DLRSM than other concentrations in 50% and 100% of DLRSM. The physico-chemical parameters viz. light intensity (2685 to 2773 lux/m2/s), temperature (29.6 to 31.5°C), pH (8.3 to 9.9), alkalinity (1150 to 3032 mg/L), Nitrate-N (1.32 to 6.30 mg/L) and phosphate-P (9.75 to 61.50 mg/L) were within optimum level during the culture period.

Formulation of Cost-effective Medium Using Urea as a Nitrogen Source for Arthrospira platensis Cultivation under Real Environment

Annual Research & Review in Biology, 2018

Even though Arthrospira is a well-known superfood, it is not extensively commercialized in developing countries like Malaysia due to the high production cost with low biomass yield. Based on literature, the algal production cost can be discounted by reducing the cost of medium utilizing cheaper and readily available chemicals. Therefore, the present study was conducted to experiment the prospect of Arthrospira platensis cultivation in newly designed medium with commercial or industrial grade fertilizers under real environment. Consequently, growth and yield of A. platensis was investigated under outdoor condition using modified Kosaric medium (MKM) which was designed by substituting the major laboratory chemicals in standard Kosaric medium (SKM) with commercial grade baking soda, sea salt, urea, phosphoric acid, potassium hydroxide and Epsom salt. Urea as an alternative nitrogen resource to sodium nitrate was pulse-fed throughout the cultivation period. The algal growth was measured through optical density, biomass dry weight and chlorophyll a content. The algal yield was determined by calculating its productivity and specific growth rate. The growth and yield of A. platensis was significantly higher (p < 0.05) in MKM in terms of optical density with 2.541 ABS, biomass dry weight with 1.30 g L-1, chlorophyll a content with 12.96 mg L-1, productivity with 0.141 g L-1 d-1 and specific growth rate with 0.253 µ d-1 compared to SKM in eight days of cultivation period. The present finding showed the potential of MKM in lowering the medium cost up to 97% compared to SKM without compromising the algal yield under natural condition with proper cultivation techniques such as preadaptation and fed-batch addition of urea in the late evening.

Variation of Spirulina maxima biomass production in different depths of urea-used culture medium

Brazilian journal of microbiology : [publication of the Brazilian Society for Microbiology], 2015

Fewer studies have assessed the outdoor cultivation of Spirulina maxima compared with S. platensis, although the protein content of S. maxima is higher than S. platensis. Spirulina growth medium requires an increased amount of NaHCO3, Na2CO3, and NaNO3, which increases the production cost. Therefore, the current study used a low-cost but high-efficiency biomass production medium (Medium M-19) after testing 33 different media. The medium depth of 25 cm (group A) was sub-divided into A1 (50% cover with a black curtain (PolyMax, 12 oz ultra-blackout), A2 (25% cover), and A3 (no cover). Similarly the medium depths of 30 and 35 cm were categorized as groups B (B1, B2, and B3) and C (C1, C2, and C3), respectively, and the effects of depth and surface light availability on growth and biomass production were assessed. The highest biomass production was 2.05 g L-1 in group A2, which was significantly higher (p &lt; 0.05) than that in all other groups and sub-groups. Spirulina maxima died in ...

Assessment of the physico-chemical properties and specific growth rate (SGR) of Spirulina platensis in lab scale cultivation

International Journal of Fisheries and Aquatic Research, 2022

An experiment was conducted to evaluate the specific growth rate (SGR) and affiliated physico-chemical attributes of Spirulina platensis in supernatant of three different concentrations of digested rotten guava (DRG) and kosaric medium (KM) as control. Three different concentrations such as 20, 40 and 60 rotten guavas were allowed to digest under aerated condition. After 34 days, the reddish white colored supernatant was screened and taken in 2.0 L conical flask with three replications. Then, Spirulina was inoculated to grow in these three digested rotten guava media (DRGM) (treatments) with the addition of 9.0 g/L NaHCO3, micronutrients and KM for a period of 14 days. The cell weight of Spirulina was attained a maximum of 12.43±0.20 mg/L (dry wt. basis) in KM followed by 0.818 ± 0.003, 0.815 ± 0.0015 and 0.809± 0.0012 mg/L in supernatant of 60, 20 and 40% DRGM, respectively. The percentage of crude protein (53.35 ± 0.32%) of Spirulina grown in supernatant of 40% DRGM significantly (p < 0.05) lower than that of cultured in KM (58.36 ± 0.32 %). But crude lipids (10.15 ± 0.14%) of Spirulina cultured in supernatant of 60% DRGM was significantly (P < 0.05) and almost two times higher than that of Spirulina grown in KM (6.30 ± 0.22%). It means that for the production of high lipid content in Spirulina, supernatant of DRGM may be used. The physico-chemical parameters viz. light intensity (2748 to 2768 lux/m 2 /s), temperature (19.0 to 22.2°C), pH (8.1 to 10.6), alkalinity (1522 to 2698 mg/L), nitrate-N (1.25 to 3.64 mg/L) and phosphate-P (11.30 to 55.40 mg/L) were within the optimum level during the culture period. So, mass culture of Spirulina may be practiced in supernatant of 60% DRGM.

Growth Enhancement of Spirulina platensis through Optimization of Media and Nitrogen Sources

Egyptian Journal of Botany

PIRULINA has drawn attention throughout the last decades. It is an essential source of valuable products, such as proteins, phycobilins, carotenoids, phenolics, and unsaturated fatty acids. These products had been used in medicine, pharmaceutical, and agriculture. In this study, the effect of different growth media on Spirulina platensis was studied after the cultivation at optimum growth conditions; continuous light intensity (60μmol photons m-2 s-1), temperature (25±3ºC), and pH (9.0 ± 0.2). The growth was estimated through 42 days by optical density (OD), cell counting (CC), and chlorophyll contents. The results showed that Kuhl's medium was the optimum for S. platensis with the highest results, i.e.: (OD), (CC) and Chlorophyll content increased 11.57 times, 19.55 times, and 22.66 times of the initial record, respectively. KNO 3 showed the best nitrogen source for S. platensis, where the different parameters of growth elevated to 3.56 times OD, 7.33 times CC, and 1.91 total chlorophyll more than their corresponding control.

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

Energy Reports

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.

Batch and fed-batch cultivations of Spirulina platensis using ammonium sulphate and urea as nitrogen sources

Aquaculture, 2005

The cyanobacterium Spirulina platensis is an attractive source of chlorophyll, a green pigment used in food, pharmaceutical and cosmetic industries, and other high-value cell components. Moreover, it can be easily and cheaply recovered by filtration from the cultivation medium. In this work, the replacement of potassium nitrate with ammonium sulphate (A) and urea (U) as cheaper nitrogen sources has been investigated: previous research work did in fact demonstrate that urea has no effect on the final chlorophyll content of the cultures. Several batch and fed-batch protocols were tested, modelled and compared in this work for the first time. It was demonstrated that the kinetics of S. platensis growth at 308C, using urea as nitrogen source, can be comparable and even better than the one achievable with the classic nitrate-based culture media. Adoption of an appropriate slowly increasing urea feeding rate prevented the accumulation of ammonia in the medium as well as its well-known inhibition of biomass growth; therefore, the use of urea should be recognized as a possible way to decrease the costs of a large-scale plant for the production of this cyanobacterium. D

Influence of chemical and environmental factors on the growth performance of Spirulina platensis strain SZ100

The cyanobacterium Spirulina platensis has been widely used by humans due to its high nutritional value and medicinal uses as well as animal feed. Our study investigated the influence of concentration of Zarrouk media, replacing high concentration of sodium nitrate with urea, pH levels, light intensities and temperature regimes under indoor and outdoor conditions on the growth rates of this microalga. We found that the half concentration of Zarrouk media was optimum for the cultivation of this alga under both indoor 1.77 O.D.) and outdoor conditions (1.74 O.D.). Lower concentration of urea fertilizer (0.15 gl -1 ) can be used as alternative inexpensive effective nitrogen source compared to the high concentration of sodium nitrate (2.5 gl -1 ) in the growth media. The optimization of the physiological growth rates of this algal strain was maintained at moderate alkalinity of 7 , 8 and 9 pH, (0.95, 1.92, and 1.49 O.D.), light intensities of 1500-2500 lux (1.68-1.96 O.D.), and temperature regimes of between 25°C and 30°C (1.83-1.88 O.D.). Therefore, this algal strain can be cultivated in large-scale open system using the available natural ponds under the suitable environmental conditions of Malaysia (24 -35°C).

Growth performance analysis of Spirulina platensis production by substituting K2SO4-K of kosaric medium with MOP-K

Bangladesh Journal of Botany, 2019

Five media were formulated with 0% (control, T1), 25% (T2), 50% (T3), 75% (T4) and 100% (T5) inclusion of low-cost muriate of potash (MOP)-potassium (K) replacing high-cost reagent K2SO4-K and Spirulina platensis was cultured for 18 days. Cell dry weight, optical cell density and chlorophyll-a content of S. platensis cultured in five treatments were registered at every three-day interval and economic performance was calculated to observe the effect of K2SO4-K replacement with MOP-K. The cell biomass production and chlorophyll-a content of S. platensis cultured in 25 and 50% use of MOP-K instead of K2SO4-K (T2 and T3) did not represent any significant difference with the control treatment of 100% K2SO4-K (T1). However, further addition of MOP-K in T4 and T5 significantly reduced the cell growth and pigment content of S. platensis. In addition, a significant reduction of production cost was calculated as more percentage of K2SO4- K was replaced with MOP-K.

Culturing Chaetoceros muelleri using simplified mediums-effects on production and biochemical quality

Land-based bivalve aquaculture depends on large-scale cultures of live microalgae for food. The intensity of large-scale microalgal production is important for cost-effectiveness. Using Walne's medium as the control, simplified media containing nitrogen, phosphorus, silica, iron, manganese and vitamins were designed to determine the impact of nitrogen source and molar N:P ratio (sodium nitrate, NO 3 9:1, ammonium chloride, NH 4 9:1 and NH 4 25:1) on growth, dry-weight biomass, culture longevity and lipid content of Chaetoceros muelleri, a diatom commonly used in shellfish aquaculture. During the exponential phase (day 6), dry-weight production in simplified media was similar to controls, indicating that this microalga can grow successfully on simplified media and use ammonium as the nitrogen source. The cultures grown on nitrate or ammonium differed in their time-course. Low nitrogen concentration in cultures grown with nitrate caused the collapse of these cultures within 11-13 days, after a short stationary phase. Cultures grown with ammonium had a longer stationary phase and were still alive on day 20, in spite of the low nitrogen concentrations observed after day 13 in cultures grown with NH 4 9:1. During stationary phase (day 18) there was an increase in lipid content of algae under conditions of low nitrogen availability (NH 4 9:1) and extended low phosphorus availability (NH 4 25:1). Considering dry weight production, culture longevity, nutrient efficiency and lipid composition, simplified media containing ammonium, phosphorus, silica, iron, manganese and vitamins are a viable and profitable choice for batch culture of C. muelleri. In the exponential phase, the simplified medium NH 4 9:1 was as effective as the control. Overall, both of the simplified media using ammonium are effective and suitable, depending on the purpose of the cultures and whether lipid contents (NH 4 9:1), dry weight biomass (NH 4 25:1) or nitrogen input and output (NH 4 9:1) are desired.

Evaluation of Chemical Composition for Spirulina platensis in Different Culture Media

2014

Spirulina platensis was cultivated in laboratory under controlled conditions in four different culture media, BG-11, modified BG-11, Zarrouks (ZM) and synthetic human urine (SHU). The effect of culturing media on chemical composition, amino acids content, fatty acids profile and minerals content were determined. The highest amount of protein (59.8%) was recorded when grown in BG-11. Whereas, modified BG-11 was the best medium in regard to both amino acids contents and maximum total lipid (8.13%). The most important unsaturated fatty acid γ-linolenic, was found at maximum percentage (4.7%) when grown in SHU medium. Whereas ZM was the best medium to obtain the highest percentage of arachidoic acid (17.63%).The highest percentage of ash in S. platensis was recorded when grown in ZM. Regarding to the minerals content, the maximumP, Ca, Mg, Zn and Cu (182.7, 155.8, 8.4, 5.1 and 5.5 mg/100g DW, respectively) were recorded in BG- 11, while growing in ZM displayed the highest amount of K, N...

Production and nutritive value of Spirulina platensis in reduced cost media Production and hosting by Elsevier

This study aimed to provide a cost effective medium to large scale production of Spirulina platensis. This intention was implemented by substituting all the nutrients present in Zarrouk's medium (SM) with cheaper and locally available commercial fertilizers and chemicals. The Reduced Cost medium contained single super phosphate (SSP), commercial sodium bicarbonate, Muriate of potash (MOP) and crude sea-salt, (Syahat salt). Four grades of nitrogen concentrations representing 10%, 20%, 30% and 40% of SM nitrogen concentration (29.42 mM-N) were taken from ammonium nitrate (Treatments 1–4) or urea (Treatments 5–8) respectively, for testing. The alga was grown for 33 days at 30 ± 2 °C, pH 9, 30 lEm 2 s À1 irradiance. The growth characteristics (maximum biomass X m , cell productivity P x , specific growth rate l m and chlorophyll concentration), and biochemical composition (proteins, carbohydrates and lipids) of the alga grown in these media were compared with that cultivated in SM. Significant differences in the growth parameters and biochemical composition were observed for the different nitrogen sources and concentrations. The results revealed that S. platensis could utilize ammonium nitrate most efficiently and that growth was enhanced with increasing the concentrations of ammonium nitrate giving maximum biomass at 0.353 g/L (Treatment 3). Further increasing the concentration limited growth. The growth parameters in urea showed a significant decrease associated with increasing urea concentrations. The maximum bio-mass, chlorophyll and protein yield (0.813 ± 0.018 mg/L, 0.0685 ± 0.0024 lg/L and 52.62%, respectively) were recorded using Treatment 3 which was comparable with that of SM (0.840 ± 0.008 mg/L, 0.0701 ± 0.0089 lg/L and 52.95%, respectively). The results indicated that the newly prepared medium can be used profitably for large-scale mass production of protein-rich Spirulina and yields similar performance with cost effective to Zarrouk's medium.

Repeated fed-batch cultivation of Arthrospira ( Spirulina) platensis using urea as nitrogen source

Biochemical Engineering Journal, 2009

Arthrospira (Spirulina) platensis (Nordstedt) Gomont was autotrophically cultivated for biomass production in repeated fed-batch process using urea as nitrogen source, with the aim of making large-scale production easier, increasing cell productivity and then reducing the production costs. It was investigated the influence of the ratio of renewed volume to total volume (R), the urea feeding time (t f ) and the number of successive repeated fed-batch cycles on the maximum cell concentration (X m ), cell productivity (P x ), nitrogen-to-cell conversion yield (Y x/n ), maximum specific growth rate ( m ) and protein content of dry biomass. The experimental results demonstrated that R = 0.80 and t f = 6 d were the best cultivation conditions, being able to simultaneously ensure, throughout the three fed-batch cycles, the highest average values of three of the five responses (X m = 2101 ± 113 mg L −1 , P x = 219 ± 13 mg L −1 d −1 and Y x/n = 10.3 ± 0.8 g g −1 ).

Biomass production and growth performance of Momela Lake’s spirulina (Arthrospira fusiformis) cultured under urea and N: P: K fertilizers as cheaper nitrogen sources

International Journal of Biological and Chemical Sciences

Spirulina species are world widely known for their ability to produce high quantities of useful metabolites such as protein, fatty acids and vitamins. One of the major challenges in production of this microalgae is the cost and composition of culture medium. In the present study, effect of two culture media with agricultural fertilizers as nitrogen sources viz. urea containing medium (UM) and N: P: K containing medium (NPKM) on production of a locally found spirulina (Arthrospira fusiformis) was investigated. Zarrouk medium (ZM) was used as a standard, other culture conditions included 67.5 µmol m-2 s-1 radiation, 10 pH and 30 ºC temperature. A. fusiformis was isolated from Momela Lake in Arusha National Park Tanzania. There was no difference (p > 0.05) in mean biomass production (BM mean) and doubling time (DT) between ZM (1.205 g/L, 1.437 days respectively) and UM (1.168 g/L, 1.63 days respectively). Significantly higher (p < 0.05) maximum biomass BM max production and exponential growth rate (µ) in a sequential order was from ZM (1.844 g/L, 0.483/day respectively), UM (1.6 g/L, 0.425/day respectively) and NPKM (0.57 g/L, 0.273/day). It appeared that the wild-isolated A. fusiformis was able to grow well in less costly UM showing high potential for mass production.

Simultaneous use of urea and potassium nitrate for Arthrospira (Spirulina) platensis cultivation

Urea has been considered as a promising alternative nitrogen source for the cultivation of Arthrospira platensis if it is possible to avoid ammonia toxicity; however, this procedure can lead to periods of nitrogen shortage. This study shows that the addition of potassium nitrate, which acts as a nitrogen reservoir, to cultivations carried out with urea in a fed-batch process can increase the maximum cell concentration (X m ) and also cell productivity (P X ). Using response surface methodology, the model indicates that the estimated optimum X m can be achieved with 17.3 mM potassium nitrate and 8.9 mM urea. Under this condition an X m of 6077 ± 199 mg/L and a P X of 341.5 ± 19.1 mg L -1 day -1 were obtained.

Cultivation of Spirulina maxima in medium supplemented with sugarcane vinasse

Bioresource technology, 2016

The feasibility of sugarcane vinasse as supplement in growth medium of Spirulina maxima was investigated. The cell was cultivated under autotrophic (no vinasse, 70μmolphotonsm(-2)s(-1)), heterotrophic (no light, culture medium supplemented with vinasse at 0.1% v/v and 1.0% v/v) and mixotrophic conditions (70μmolphotonsm(-2)s(-1), vinasse at 0.1% v/v and 1.0% v/v). These preliminary results suggested a cyclic two-stage cultivation - CTSC, with autotrophic condition during light phase of the photoperiod (12h, 70-200μmolphotonsm(-2)s(-1)) and heterotrophic condition during dark phase (12h, 3.0% v/v vinasse). The adopted CTSC strategy consisted in three cycles with 75% withdrawal of suspension and reposition of medium containing 3.0% v/v vinasse, separated by autotrophic rest periods of few days between cycles. Results show an increase of biomass concentration between 0.495gL(-1) and 0.609gL(-1) at the 7th day of each cycle and high protein content (between 74.3% and 77.3% w/w).

Cultivation of Spirulina platensis by continuous process using ammonium chloride as nitrogen source

Biomass and Bioenergy, 2007

This work is focused on the influence of dilution rate (0.08pDp0.32 d À1 ) on the kinetics of continuous cultivation of Spirulina platensis at two different concentrations of ammonium chloride (N 0 ¼ 1.0 and 10 mM) as nitrogen source. Cell productivity increased in both series of runs up to Dffi0.12-0.16 d À1 , and then decreased. While at N 0 ¼ 1.0 mM biomass washing was certainly the cause of progressive cell concentration decrease, a combination of this phenomenon with the toxic effect of excess ammonia was responsible, at N 0 ¼ 10 mM and DX0.20 d À1 , for quick stop of cell growth just beyond the achievement of maximum cell productivity (92.4 mg l À1 d À1 ). Similar profile was observed for protein productivity, that achieved a maximum value of 67.0 mg l À1 d À1 , because of the very high protein content (72.5%) of biomass produced under these conditions. The yield of nitrogen-to-biomass was much higher at the lower N 0 , because of the low protein content, and reached a maximum value of 9.7 g g À1 at D ¼ 0.08-0.12 d À1 . The yield of nitrogen-to-protein showed less marked difference, being most of the nitrogen present in the cell as proteins or free amino-acids. r

A study on growth performance of Spirulina platensis in different concentrations of rotten apple as a carbon source

International Journal of Excellence Innovation and Development, 2019

An experiment was conducted on culture and growth performance of Spirulina platensis in various concentrations of rotten apple medium (RAM) and Kosaric Medium (KM). The observation was conducted for three months from March to May at the Live Food Culture Laboratory, Department of Aquaculture, Faculty of Fisheries, Bangladesh Agricultural University. Culture of S. platensis was performed in 1.0L glass flasks in three different media such as 2.5, 5.0 and 10% and KM with three replications under fluorescent light in light : dark (12 hr : 12 hr) condition of a period of 14 days. Growth performances of S. platensis varied from one medium to another. The initial cell weight of S. platensis was 0.0023 mg/L and a maximum cell weight of 12.44 mg/L was found in KM and 10.468 mg/L in RAM on 10th day of culture. It was also observed that, the initial chlorophyll a content of S. platensis was 0.0015 mg/L which was attained at a highest content of 10.54 mg/L in KM and 12.35 mg/L in RAM on 10th day of culture. A decreasing trend of cell weight was observed from 10th day of culture. The growth of S. platensis was significantly (p<0.05) better in 5.0% Digested Rotten Apple Medium (DRAM) than other concentrations 2.5% DRAM and 10% DRAM. From the results obtained in the present study, it was summarized that the growth of S. platensis was better in the concentrations of 5.0% DRAM than other concentrations of RAM. Thus, the concentration of 5.0% DRAM is most suitable for S. platensis culture compare with standard KM. These media are easily available and most inexpensive in contrast of Bangladesh. So digested rotten apple can be used for commercially and economically viable mass culture of S. platensis.

Fed-batch addition of urea for Spirulina platensis cultivation

Enzyme and Microbial Technology, 2003

Previous results of Spirulina platensis cultures, carried out by supplying intermittently urea as nitrogen source at exponentially increasing feeding rate, have been used to perform a bioenergetic and thermodynamic study on the growth of this cyanobacterium as well as on its photosynthetic efficiency. Simple material, enthalpy and Gibbs energy balances have been applied to the results obtained alternately varying either the total time of nitrogen source feeding (9 < t T < 15 days) or the overall added mass of urea per unit reactor volume (250 < m T < 750 mg l −1 ). The number of photons involved in the autotrophic growth has been estimated for every tested condition. The progressive increase in this bioenergetic parameter during cultivations demonstrated that the photosynthesis efficiency decreased with increasing biomass concentration. The estimated percentages of the different energy components suggest that less than one-third of the absorbed Gibbs energy was fixed by the system at 25 • C to increase its own enthalpic content, while only 6% was recovered as ATP and about two-thirds were released as heat.