Spirulina culture in sea-water

Summary Laboratory experiments using small raceway ponds have shown that Spirulina maxima can be adapted easily to grow in sea-water supplemented with nitrate, phosphate, bicarbonate, and Fe-EDTA. To prevent precipitate formation, phosphate was supplied by diffusion through a dialysis membrane; the amount of Na-bicarbonate added was low (100 ppm) and the pH was kept in the range 8.6–8.8 by bubbling CO₂ into the culture.No significant differences have been noticed in productivity or in the chemical composition of the biomass between cultures in sea-water and in the standard bicarbonate medium. Cultures subjected to light/dark cycles of 12/12 h showed a higher respiration rate in sea-water than in the bicarbonate medium.The higher weight loss in the sea-water medium in the dark was counterbalanced by an increased synthesis of carbohydrates during the light period.     

Utilization of seawater-urea as a culture medium for Spirulina maxima.

The possibilities of utilization of seawater enriched with ureas as the culture medium for a blue-green alga, Spirulina maxima, were investigated. Pretreatment by precipitation with NaHCO3 and (or) Na2CO3 was found essential to remove the excess amounts of Ca2+ and Mg2+ present in seawater prior to cultivation. A culture medium as good as the synthetic medium reported in the literature for the growth of S. maxima was obtained after treating seawater with NaHCO3 (19.2 g/L) at pH 9.2 and 35 degrees C for 2 h, filtering to remove precipitates, and enriching with K2HPO4 (0.5 g/L), NaNO3 (3.0 g/L), and FeSO4 (0.01 g/L). The same results were obtained by substituting a small amount (0.2 g/L or less) of either crystalline or polymerized urea for the NaNO3 in the above medium. Growth of S. maxima was inhibited at higher concentration of urea in the culture medium. The inhibition effect was due to the partial decomposition of urea into ammonia in alkali medium. Tests conducted on the 130-L cultivation open pond also confirmed that the seawater-urea medium supports growth of S. maxima as well as the best known synthetic medium.     

Inorganic Pyrophosphatase from Spirulina maxima

An inorganic pyrophosphatase was isolated from a cyanobacteriumSpirulina maxima. The properties of the enzyme such as pH optimum,substrate and metal ion specificities and the effects of inhibitorswere determined. (Received November 4, 1983; Accepted May 8, 1984)     

Growth of Spirulina maxima on cow-manure wastes

Experiments were carried out on culturing the blue-green alga Spirulina maxima on raw cow-manure wastes in an outdoor pond. Improved growth was obtained at pH above 9.2 and temperature above 32°C, with half the radiation intensity required for other green algal species. A yield of 3 g/liter, in terms of total suspended matter, was achieved. The main advantage of this method is that S. maxima removes nutrients and thus serves as an alternative protein source.     

Unfolding kinetics of glutathione reductase from cyanobacterium Spirulina maxima

The kinetics of the irreversible unfolding of glutathione reductase (NAD[P]H:GSSG oxidoreductase, EC 1.6.4.2.) from cyanobacterium Spirulina maxima was studied at pH 7.0 and room temperature. Denaturation was induced by guanidinium chloride and the changes in enzyme activity, aggregation state, and tertiary structure were monitored. No full reactivation of enzyme was obtained, even after very short incubation times in the presence of denaturant. Reactivation plots were complex, showing biphasic kinetics. A very fast early event in the denaturation pathway was the dissociation of tetrameric protein into reactivatable native-like dimers, followed by its conversion into a nonreactivatable intermediary, also dimeric. In the final step of the unfolding pathway the latter was dissociated into denatured monomers. Fluorescence measurements revealed that denaturation of S. maxima glutathione reductase is a slow process. Release of the prostethic group FAD was previous to the unfolding of the enzyme. No aggregated species were detected in the unfolding pathway, dismissing the aggregation of denatured polypeptide chains as the origin of irreversibility. Instead, the transition between the two dimeric intermediates is proposed as the cause of irreversibility in the denaturation of S. maxima glutathione reductase. A value of 106.6 +/- 3 kJ mol(-1) was obtained for the activation free energy of unfolding in the absence of denaturant. No evidence for the native monomer in the unfolding pathway was obtained which suggests that the dimeric nature of glutathione reductase is essential for the maintenance of the native subunit conformation.     

Reproductive and peri- and postnatal evaluation of Spirulina maxima in mice

Spirulina maxima, provided by Sosa Texcoco Company (México City), was administered to mice of both sexes in a fertility study, at concentrations of 0, 10, 20 and 30% incorporated into the diet. Males were fed for nine weeks while females, for two weeks, and feeding continued during the mating period and gestation. On the other hand, in a peri- and postnatal study, the alga was given only to females at the same concentrations from day 15 of gestation until day 21 post-partum. Treatments were not associated with any adverse effect on reproductive performance, pregnancy rate, number of corpora lutea, resorptions or number of live or dead fetuses. There was no increase in the number of abnormal pups at caesarean section. Length of gestation, parturition status, and litter values were unaffected by treatment. However, there was a statistically significant reduction in bodyweight and survival rate on postnatal days 0–4 at the high dose group in the peri- and postnatal study. The reproductive performance of F₁ generation was normal in all groups. We conclude that S. maxima is not toxic to reproduction. This revised version was published online in September 2006 with corrections to the Cover Date.     

极大螺旋藻藻胆蛋白提纯工艺初试

目的:螺旋藻富含藻胆蛋白,其附加值高,本实验对螺旋藻藻胆蛋白提取工艺做初步探索;方法:比较了组织捣碎法,冻融法,超声波法释放螺旋藻藻胆蛋白的效果,并用硫酸铵盐析,羟基磷灰石层析进一步提纯,对结果作了吸收光谱和SDS电泳鉴定;结果:显示超声波法破碎效果好,两次羟基磷灰石层析所得蛋白纯度较高;结论:表明本实验流程相对以往工艺经济,省力,省时,对螺旋藻藻胆蛋白的规模提取有一定实用价值。     

Cadmium uptake by Spirulina maxima: toxicity and mechanism

Cadmium uptake by Spirulina maxima cells was more pronounced in living than in dead cells, with a maximum recovery of 47.63mg Cd/g cells for living cells and 37.00mg Cd/g cells for inactivated cells. When in the medium at 1.2mg/l, cadmium affected cell growth and diminished cell productivity. Cadmium was detected in the outer and inner faces of the external membrane, essentially in the lipid layer.     

Detailed study of anaerobic digestion of Spirulina maxima algal biomass

Biomass of the blue-green alga Spirulina maxima was converted to methane using continuous stirred tank digesters with an energy conversion efficiency of 59%. Digesters were operated using once-a-day feeding with a retention time (theta) between 5 and 40 days, volatile solid concentrations (S(to)) between 20 and 100 kg VS/m(3), and temperatures between 15 and 52 degrees C. The results indicated a maximum methane yield of 0.35 m(3) (STP)/kg VS added at theta 30 days and S(to) 20 kg VS/m(3). Under such conditions, the energy conversion of the algal biomass to methane was 59%. The maximum methane production rate of 0.80 m(3) (STP)/m(3) day was obtained with theta= 20 days and S = 100 kg VS/m(3). The mesophilic condition at 35 degrees C produced the maximum methane yield and production rate. The process was stable and characterized by a high production of volatile acids (up to 23, 200 mg/L), alkalinity (up to 20, 000 mg/L), and ammonia (up to 7000 mg/L), and the high protein content of the biomass produced a well buffered environment which reduced inhibitory effects. At higher loading rates, the inhibition of methanogenic bacteria was observed, but there was no clear-cut evidence that such a phenomenon was due to nonionized volatile acids or gaseous ammonia. The kinetic analysis using the model proposed by Chen and Hashimoto indicated that the minimum retention time was seven days. The optimum retention time increased gradually from 11 to 16 days with an increase in the initial volatile solid concentration. The kinetic constant K decreased with the improvement in the digester performance and increased in parallel with the ammonia concentration in the culture media.     

Dimer-tetramer equilibrium of glutathione reductase from the cyanobacterium Spirulina maxima

Glutathione reductase [NAD(P)H:GSSG oxidoreductase; EC 1.6.4.2] from cyanobacterium Spirulina maxima exists as an equilibrium system between a dimer (S20,W = 5.96) and a tetramer (S20,W = 8.49) which has a very slow interconversion rate at neutral pH. Our results showed that the apparent dissociation constant (kd) was 4.61 X 10(-7) M. The proportion of both forms at pH 7.0 did not alter at either 4 or 25 degrees C. However, electrophoretic analysis at various pH values showed that at 25 degrees C a gradual transition takes place between oligomers with an apparent pKa of 7.55. When dimers aggregate to form tetramers, the reaction involves the uptake of eight protons (K = 1.58 X 10(-64) M9). At pH 7.7, the equilibrium shifts completely from dimers-tetramers to dimers when temperature is increased, which would suggest that the dissociation is an endothermic process. Thermodynamic parameters obtained from the temperature study show that the dissociation of glutathione reductase is characterized by positive entropy and enthalpy changes. Neither NADPH nor GSSG have any effect on the dimer-tetramer equilibrium. Measurements of reductase activity indicate that the tetramer is almost certainly active, whereas the dimer is either less active or inactive.     

Growth of Spirulina maxima algae in effluents from secondary waste-water treatment plants

Spirulina maxima, a high protein alga, was grown in effluents from the London municipal waste treatment plant. Optimum growth conditions were developed, the composition of algae and the removal of nitrogen and phosphorus in effluents were studied. The advantages of this process in tertiary waste-water treatment and the quality of the single cell protein were investigated.     

Cu~(2 )对蓝藻Spirulina maxima光合作用的抑制机理

Cu2 对S.maxima的生长和光合放氧均有抑制作用;高浓度Cu2 使藻细胞中藻胆体产生的特征光吸收和荧光显著下降,表明藻胆体是Cu2 作用位点之一。Cu2 可促使离体的藻蓝蛋白变性,使其光吸收和荧光减弱、荧光偏振度减小,而别藻蓝蛋白对Cu2 的作用不敏感。根据这些结果推测,Cu2 可能通过对藻胆体中的藻蓝蛋白的作用,抑制藻胆体的光能吸收和传递。     

螺旋藻多糖的药理作用研究

螺旋藻多糖（Ｐｏｌｙｓａｃｃｈａｒｉｄｅ ｏｆ Ｓｐｉｒｕｌｉｎａ）是从螺旋藻中提取的一种无毒的天然产物,具有多种生物学活性。为进一步探讨螺旋藻多糖的作用,本文以小鼠为动物模型,观察极大藻多糖对小鼠生物功能的影响。螺旋藻多糖可以提高受γ射线致死剂量照射的小鼠３０天内的存活率促进小鼠多能干细胞和造血祖细胞的增殖和分化;促进受到辐射损伤的小鼠造血系统的恢复,增强小鼠的抗辐射能力。螺旋藻多糖可以提高小鼠     

Outdoor mass culture ofAzolla spp.: yields and efficiencies of nitrogen fixation

Summary The productivity of three species of Azolla (A. pinnata, A. filiculoides andA. caroliniana) in outdoor culture has been evaluated at different planting densities. The highest yields were obtained with biomass concentration ranging from 40 to 70g d.w. m^–2. The mean productivity over a 90 days period (from May 10th to August 10th) ranged from 10g d.w. m^–2 day^–1 forA. filiculoides up to 11.5 g d.w. m^–2 day^–1 forA. caroliniana. The nitrogen content of the dried biomasses was 48.3 mg (g d.w.)^–1 forA. pinnata, 51.5mg (g d.w.)^–1 forA. filiculoides and 52.3 mg (g d.w.)^–1 forA. caroliniana. Very little variations of the nitrogen content of the ferns during the experimental period were observed.The nitrogen-fixing efficiency of the Azolla-Anabaena azollae symbiosis grown in outdoor conditions was evaluated both by direct measurement of the amount of N₂ fixed by the culture and by the C₂H₂-reduction and H₂-evolution tests in an air atmosphere. These tests were performed outdoor under the same environmental conditions as the growing cultures. For all the species the ratios of C₂H₂-reduced to N₂-fixed were unexpectedly low, ranging from 2.04 (A. pinnata) to 1.50 (A. caroliniana).The results suggest that the reliability of the C₂H₂-reduction assay, particularly when applied to complex biological N₂-fixing systems, must be re-examined.     

Free and immobilized cultures of Spirulina maxima for swine waste treatment

We have analyzed the behavior of spirulina maxima at increasing concentration of ammonium nitrogen present in swine waste when it is either growing in suspension or immobilized in polymeric supports. We compared the response of spirulina maxima growth to different concentrations of aeration stabilized swine waste (total phosphorus, ammonium nitrogen) as a way to determine the treatment efficiency of both systems. At a dilution of 50 % of swine waste, the suspended system reached the best results for biomass concentration and nutrient removal. In the immobilized system, at dilutions of 25 and 50 % of swine waste, more than 90 % ammonium nitrogen removal was obtained, and the optimal cell concentration for immobilization was 2 g/l (wet basis).     

Glycolipids Isolated from Spirulina maxima: Structure and Fatty Acid Composition

Several glycolipids were isolated from Spirulina maxima, an edible blue-green algae, by systematic fractionation with different solvents. Structural investigation by using methylation, GC-MS, and enzymic techniques indicated that the major glycolipids are O-β-d-galactosyl-(1→l′)-2′, 3′-di-O-acyl-d-glycerol, O-α-d-galactosyl-(l-→6)-O-β-d-galactosyl-(1→l′)-2′,3′-di-O-acyl-d-glycerol and 6-sulfo-O-α-quinovosyl-(l→l′)-2′, 3′-di-O-acyl-d-glycerol. Main fatty acid components of these glycolipids were identified as palmitic acid and linoleic or linolenic acid. Based on-these fatty acid compositions, Spirulina glycolipids were compared with those in higher plants.