Biomass of Spirulina maxima enriched by biosorption process as a new feed supplement for swine

This paper deals with the new mineral feed additives with Cu produced in a biosorption process from a semi-technical scale. The natural biomass of edible microalga Spirulina sp. was enriched with Cu(II) and then used as a mineral supplement in feeding experiments on swine to assess its nutrition properties. A total of 24 piglets divided into two groups (control and experimental) were used to determine the bioavailability of a new generation of mineral feed additives based on Spirulina maxima. The control group was feed using traditional inorganic supplements of microelements, while the experimental group was fed with the feed containing the biomass of S. maxima enriched with Cu by biosorption. The apparent absorption was 30 % (P?<?0.05) higher in the experimental group. No effect on the production results (average daily feed intake, average daily gain, feed conversion ratio) was detected. It was found that copper concentration in feces in the experimental group was 60 % (P?<?0.05) lower than in the control group. The new preparation—a dietary supplement with microelements produced by biosorption based on biomass of microalgae S. maxima—is a promising alternative to currently used inorganic salts as the source of nutritionally important microelements.     

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.     

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.     

Biotransformation of codeine to morphine in freely suspended cells and immobilized cultures of Spirulina platensis

Both freely suspended cells and immobilized cultures of Spirulina platensis, a blue-green alga, biotransformed exogenously fed codeine, an opium alkaloid, to morphine. The external addition of codeine to the culture medium did not affect the growth of S. platensis. Immobilization of Spirulina in a calcium alginate gel matrix was optimized by using 2% (w/v) sodium alginate and reducing the concentration of nutrients of Zarrouk's medium, which caused destabilization of the calcium alginate gel. The accumulation of morphine increased gradually and reached maxima of 330g 100ml^–1 culture at 105h in freely suspended and 351g 100ml^–1 at 96h in immobilized Spirulina cultures. Accumulation of morphine was detected only in the medium, whereas cells did not show accumulation. The immobilized Spirulina cultures showed marginally higher conversion of codeine to morphine over freely suspended cultures.     

Outdoor mass culture of Spirulina maxima in sea-water

Summary The results of a whole year experiment on the outdoor mass culture of Spirulina maxima strain 4Mx on fertilized sea-water are reported. Carbonate and phosphate precipitation in the sea-water media was prevented by maintaining a low concentration of phosphate and by controlling the pH in the range of 8.0–8.3. The mean annual yield of biomass on sea-water plus urea as nitrogen source was 7.35 g (dry weight) m^-2· day^-1, a value slightly lower than that obtained on the standard bicarbonate medium (8.14 g · m^-2 · day^-1). On sea-water plus nitrate the yield was only 5.2 g·m^-2·day^-1. The nitrogen content of the biomass was higher in summer and lower in winter. The seasonal effect was more evident when nitrate was the nitrogen source.     

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.     

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.     

Use of extracts from oyster shell and soil for cultivation of Spirulina maxima

Calcium ion and trace metals play important roles in various metabolisms of photosynthetic organisms. In this study, simple methods were developed to extract calcium ion and micronutrients from oyster shell and common soil, and the prepared extracts were tested as a replacement of the corresponding chemicals that are essential for growth of microalgae. The oyster shell and soil were treated with 0.1 M sodium hydroxide or with 10 % hydrogen peroxide, respectively. The potential application of these natural sources to cultivation was investigated with Spirulina maxima. When compared to standard Zarrouk medium, the Spirulina maxima cultivated in a modified Zarrouk media with elements from oyster shell and soil extract exhibited increases in biomass, chlorophyll, and phycocyanin by 17, 16, and 64 %, respectively. These results indicate that the extracts of oyster shell and soil provide sufficient amounts of calcium and trace metals for successful cultivation of Spirulina maxima.     

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.     

Antimicrobial use and resistance in swine waste treatment systems

Chlortetracycline and the macrolide tylosin were identified as commonly used antimicrobials for growth promotion and prophylaxis in swine production. Resistance to these antimicrobials was measured throughout the waste treatment processes at five swine farms by culture-based and molecular methods. Conventional farm samples had the highest levels of resistance with both culture-based and molecular methods and had similar levels of resistance despite differences in antimicrobial usage. The levels of resistance in organic farm samples, where no antimicrobials were used, were very low by a culture-based method targeting fecal streptococci. However, when the same samples were analyzed with a molecular method detecting methylation of a specific nucleotide in the 23S rRNA that results in resistance to macrolides, lincosamides, and streptogramin B (MLSB), an unexpectedly high level of resistant rRNA (approximately 50%) was observed, suggesting that the fecal streptococci were not an appropriate target group to evaluate resistance in the overall microbial community and that background levels of MLSB resistance may be substantial. All of the feed samples tested, including those from the organic farm, contained tetracycline resistance genes. Generally, the same tetracycline resistance genes and frequency of detection were found in the manure and lagoon samples for each commercial farm. The levels of tetracycline and MLSB resistance remained high throughout the waste treatment systems, suggesting that the potential impact of land application of treated wastes and waste treatment by-products on environmental levels of resistance should be investigated further.     

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。     

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.     

Microbiological aspects of aerobic thermophilic treatment of swine waste

A thermophilic strain (D2) identified as a Bacillus sp. was isolated from an aerobic digestor of swine waste after several months of operation at 55 degrees C. Aerobic thermophilic batch treatment of swine waste inoculated with strain D2 was studied in a 4-liter fixed-bed reactor. Stabilization of the waste was achieved in less than 30 h when the original chemical oxygen demand (COD) was between 15 and 20 g/liter or in less than 48 h when the COD was around 35 g/liter. When the COD was higher than 30 g/liter, the pH of the waste reached 9.2 to 9.5 during the treatment, and periodic adjustment of the pH to 8.5 was necessary to maintain the activity of the biofilm. In this reactor, ammoniacal nitrogen was completely eliminated by desorption in less than 72 h of incubation. The different packing materials used resulted in similar rates of degradation of organic matter. The thermophilic treatment was also efficient in the 75-liter digestor, and stabilization was achieved in approximately 50 h. A bank of 22 thermophilic bacterial strains originating from different environments and adapted to the thermophilic treatment of swine waste was established. This thermophilic treatment allows, in one step, rapid stabilization of the waste, elimination of the bad smell, and complete elimination of ammonia nitrogen by stripping.     

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.     

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.     

LD和YAG激光对极大螺旋藻生理特性的影响

采用Nd:YAG和LD激光辐射极大螺旋藻。Nd:YAG激光波长λ=532nm,功率P＝500mW,功率密度S＝160mW/cm^2,辐射10min,λ=1060nm,功率P＝7W,功率密度S＝35.84mW/cm^2,辐照20s:Nd:YAG激光（λ=532nm）辐照10min,再用LD激光（波长λ=650nm,功率P＝40mW功率密度S＝13mW/cm^2)辐照20min。实验结果表明,所设计的三种实验方 均能促进极大螺旋藻生长、β－胡萝卜素积累和胞外多糖含量的增加,且波长532nm的Nd:YAG激光的促进作用最明显,它可使β－胡萝卜素提高14＝．31％,胞多糖含量增加19．12％,红外光谱分析表明,经激光辐照后的藻细胞官能基团没有发生变化。     

Role of sodium ions and their uptake by cells of cultured blue-green algae, Spirulina platensis and Spirulina maxima

The growth of the blue-green algae Spirulina platensis and Spirulina maxima, cultured in complete mineral Zarouk medium containing Na+ or Na+-deficient medium, was studied over a period of 24 h. The optical densities of S. platensis and S. maxima cells, determined during the last hour of exposure to sodium deficiency, amounted to 55.6 and 32.6%, respectively, of the optical densities of the same cells grown in complete Zarouk medium. Moreover, the cultures grown in Na+-deficient medium exhibited increased ability to take up sodium (which was low in S. platensis and S. maxima cells cultured in complete mineral medium). It is concluded that the two species studied are characterized by periodic, on the order of minutes, changes in the cellular uptake and release of sodium.     

Role of Sodium Ions and Their Uptake by Cells of Cultured Blue-Green Algae, Spirulina platensis and Spirulina maxima

The growth of the blue-green algae Spirulina platensis and Spirulina maxima, cultured in complete mineral Zarouk medium containing Na⁺ or Na⁺-deficient medium, was studied over a period of 24 h. The optical densities of S. platensis and S. maxima cells, determined during the last hour of exposure to sodium deficiency, amounted to 55.6 and 32.6%, respectively, of the optical densities of the same cells grown in complete Zarouk medium. Moreover, the cultures grown in Na⁺-deficient medium exhibited increased ability to take up sodium (which was low in S. platensis and S. maxima cells cultured in complete mineral medium). It is concluded that the two species studied are characterized by periodic, on the order of minutes, changes in the cellular uptake and release of sodium.