A Simple and reliable formula for assessment of maximum volumetric productivities in photobioreactors

This article establishes and discusses the consistency and the range of applicability of a simple but general and predictive analytical formula, enabling to easily assess the maximum volumetric biomass growth rates (the productivities) in several kinds of photobioreactors with more or less 15% of deviation. Experimental validations are performed on photobioreactors of very different conceptions and designs, cultivating the cyanobacterium Arthrospira platensis, on a wide range of volumes and hemispherical incident light fluxes. The practical usefulness of the proposed formula is demonstrated by the fact that it appears completely independent of the characteristics of the material phase (as the type of reactor, the kind of mixing, the biomass concentration…), according to the first principle of thermodynamics and to the Gauss‐Ostrogradsky theorem. Its ability to give the maximum (only) kinetic performance of photobioreactors cultivating many different photoautotrophic strains (cyanobacteria, green algae, eukaryotic microalgae) is theoretically discussed but experimental results are reported to a future work of the authors or to any other contribution arising from the scientific community working in the field of photobioreactor engineering and potentially interested by this approach. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

A structured model for simulation of cultures of the cyanobacterium Spirulina platensis in photobioreactors: I. Coupling between light transfer and growth kinetics

The study of the interactions between physical limitation by light and biological limitations in photobioreactors leads to very complex partial differential equations. Modeling of light transfer and kinetics and the assessment of radiant energy absorded in photoreactors require an equation including two parameters for light absorption and scattering in the culture medium. In this article, a simple model based on the simplified, monodimensional equation of Schuster for radiative transfer is discussed. This approach provides a simple way to determine a working illuminated volume in which growth occurs, therefore allowing indentification of kinetic parameters. These parameters might then be extended to the analysis of more complex geometries such as cylindrical reactors. Moreover, this model allows the behavior of batch or continuous cultures of cyanobacteria under light and mineral limitations to be predicted. (c) 1992 John Wiley & Sons, Inc.     

Harvesting of Spirulina platensis by cellular flotation and growth stage determination

AIM: To investigate an effective harvesting method for Spirulina platensis. METHODS AND RESULTS: Eighty per cent of S. platensis cells in the logarithmic growth phase were harvested by flotation when the cells were set in a static condition for 2 h. The optimum harvesting time was about day 6 of cultivation. The flotation activity of S. platensis cells was enhanced by the addition of NaCl. CONCLUSIONS: The harvesting of S. platensis by flotation is a cost-effective and straightforward method that can retain the algal quality. The optimum harvesting time of S. platensis can be predicted by the cellular protein to carbon ratio. SIGNIFICANCE AND IMPACT OF THE STUDY: Flotation harvesting is also applicable to other cyanobacteria with gas vesicles.     

The AplI Restriction-Modification System in an Edible Cyanobacterium,Arthrospira (Spirulina) platensis NIES-39, Recognizes the Nucleotide Sequence 5′-CTGCAG-3′

The effects on cholesterol absorption of oxidized cholesterols were studied in lymph-cannulated rats. When a single emulsified lipid meal containing a tracer amount of [¹⁴C]cholesterol with either 50 mg cholesterol or 50 mg oxidized cholesterol mixture was administered intragastrically, the lymphatic absorption of cholesterol for 24 h was 33.1 ± 6.3 and 21.7 ± 8.6%, respectively. Moreover, oxidized cholesterols also inhibited the absorption of triolein (85.9 ± 3.2% and 59.5 ± 18.8%). The observation may be of use since the ingestion of oxidized cholesterols tends to be increasing.     

SODIUM DEPRIVATION UNDER ALKALINE CONDITIONS CAUSES RAPID DEATH OF THE FILAMENTOUS CYANOBACTERIUM SPIRULINA PLATENSIS1

Like other alkaliphiles, the cyanobacterium Spirulina platensis (Norst.) Geitler requires sodium to function properly at elevated pH values. At pH 10.0, 150–250 mM Na⁺ were required for optimal growth, whereas 2.5 mM were sufficient for short-term photosynthetic oxygen evolution. The complete absence of sodium, however, caused S. platensis to deteriorate. O₂ evolution stopped, the absorbance at 620 nm corresponding to phycocyanin decreased, and the cells lysed within 1 h, a process accelerated by light. The activity of photosystem II, but not that of photosystem I, was affected in the process, which was irreversible unless sodium was readded within 15 minfrom the onset of the deprivation. The effect was mimicked, even in the presence of sodium, by the ionophore nigericin. We suggest that the cascade of events leading to cell lysis is primarily due to the inability of S. platensis to maintain a proton gradient (acid inside), possibly due to inactivity of a sodium/proton antiporter, as demonstrated for other alkaliphiles.     

钝顶螺旋藻突变株FBL细胞超微结构

利用透射电镜技术观察钝顶螺旋藻出发株和突变株FBL的细胞超微结构。观察结果表明L出发株和突变株均为多细胞丝状体,细胞间横隔膜清晰,细胞壁均由四层结构组成,细胞质膜内陷形成类囊体,类囊体由双层膜堆积而成,膜上附着藻胆体,类囊体与细胞壁呈垂直方向排列,细胞质内包含有充气液泡等细胞器。与出发株相比,突变株细胞壁表面较光滑,四层结构电子密度较深;类囊体膜增多、变发达;羧化体数量增多;横隔膜收缢明显。     

螺旋藻连续培养与动力学模型

在内循环气升式光生物反应器中 ,研究了钝顶螺旋藻 (SpirulinaplatensisGeitler)细胞的连续生长及其对碳源底物的利用特性。结果表明 :随着稀释率的增大 ,反应器中碳源浓度和细胞浓度分别呈上升和下降趋势 ,它们之间的关系可用Monod类型的方程很好地加以关联。细胞产率和碳消耗速率与稀释率的关系存在峰值现象 :在本实验条件下 ,最大细胞产率为 0 .36 2g/(L·d) ,最大碳消耗速率为 0 .177g/(L·d) ,此时稀释率为 0 .45 /d ,细胞浓度为OD560 =1.2 82 ,细胞对碳的得率系数为 2 .0 5 0g/g。所提出的连续培养动力学模型与实验数据拟合较好     

钝顶螺旋藻细胞的超微结构

钝顶螺旋藻是一种丝状多细胞蓝藻。经透射电源观察证实,细胞的核区无核膜,核仁,细胞质内无线粒体、叶绿体、高尔基体等细胞器分化。     

ON-LINE MONITORING OF CHLOROPHYLL FLUORESCENCE TO ASSESS THE EXTENT OF PHOTOINHIBITION OF PHOTOSYNTHESIS INDUCED BY HIGH OXYGEN CONCENTRATION AND LOW TEMPERATURE AND ITS EFFECT ON THE PRODUCTIVITY OF OUTDOOR CULTURES OF SPIRULINA PLATENSIS (CYANOBACTERIA)

The saturating pulse fluorescence technique was applied to study photoinhibition of photosynthesis in outdoor cultures of the cyanobacterium Spirulina platensis (Nordstedt) Geitler strain M2 grown under high oxygen and low temperature stress. Diurnal changes in maximum photochemical yield (F_v/F_m), photon yield of PSII (ΔF/F 'm), and nonphotochemical quenching (qN) were measured using a portable, pulse-amplitude–modulated fluorometer. When solar irradiance reached the maximum value, the F _v/F_m and ΔF/F 'm ratios of the Spirulina cultures grown under high oxygen stress decreased by 35% and 60%, respectively, as compared with morning values. The depression of the F_v/F_m and ΔF/F 'm ratios reached 55% and 84%, respectively, when high oxygen stress was combined with low temperature (i.e. 10° C below the optimal value for growth). Photoinhibition reduced the daily productivity of the culture grown under high oxygen stress by 33% and that of the culture grown under high oxygen–low temperature stress by 60%. Changes in the biomass yield of the cultures correlated well with changes in the daily integrated value of the estimated electron transport rate through the PSII (ΔF/F 'm × photon flux density). The results indicate that on-line chlorophyll fluorescence measurement is a powerful tool for assessing the photosynthetic performance of outdoor Spirulina cultures.     

大螺旋藻营养成分研究

通过对大螺旋藻的6种营养成分进行分析表明,大螺旋藻含有61％～66％蛋白质,4．5％～4．7％核酸,6％～8％碳水化合物,4％～5％粗纤维,1％～2％粗脂肪和13～14mg／100g维生素C,这些成分与极大螺旋藻及钝顶螺旋藻的成分很相似。因此大螺旋藻与钝顶螺旋藻、极大螺旋藻同样可被开发利用。     

Physiological behaviour of Arthrospira (Spirulina) maxima during acclimation to changes in irradiance

The physiological behaviour of Arthrospira (Spirulina) maxima during acclimation to sudden changes in irradiance from high (HL) to low light (LL) and vice versa was studied by following parameters concerning growth rate, pigment, carbohydrate and protein cell contents. Applying first order kinetics, the specific acclimation rates for the parameters considered were calculated. During HL to LL shift, pigments increased to compensate for a reduction in growth irradiance in order to maintain relatively high growth rates, whereas carbohydrates decreased at the highest rate. The synthesis of phycobiliproteins proceeded at a rate similar or little higher than that of chlorophyll a, indicating their importance in the light harvesting at low irradiance. During LL to HL shift, carbohydrate biosynthesis was increased, whereas pigment and protein cell contents decreased. The kinetic analysis suggested that the pigment decrease could be accounted for both by dilution through growth and in vivo degradation. During this transition, the initially high cell pigment content gave rise to a very heavy carbohydrate synthesis, which for a short time, after the shift to HL conditions, overshot the final steady-state. In the same period the specific growth rate also increased notably, overshooting the μmax. The acclimation rates of the measured parameters were faster during LL to HL transition then during the reverse. The physiological response of A. maxima during the acclimation to sudden irradiance shifts points out the ability of this cyanobacterium to alter light harvesting and highlights again the key role of carbohydrates when the cells underwent an energy crisis during down-shift. This revised version was published online in August 2006 with corrections to the Cover Date.     

螺旋藻多糖抗单纯疱疹病毒作用的实验研究

在体外进行了钝顶螺旋藻多糖(polysaccharides fromSpirulina platensis,PSP)抗单纯疱疹病毒活性的研究。以不同剂量的PSP分别作用于HSV-1及HSV-2病毒复制周期的各个环节,以病毒半数感染量(TCID50),细胞病变效应(CPE),蚀斑形成单位(PFU),MTT染色细胞保护率(MTT法)作为评价指标,判断PSP的抗病毒效果;FQ-PCR检测PSP抗病毒作用的时效关系。结果表明PSP对Vero细胞毒性极低(TC50为1750μg/mL),对HSV-1及HSV-2均无直接灭活作用,可阻滞HSV-1及HSV-2病毒吸附和抑制感染细胞内病毒的复制,但不影响病毒的释放;FQ-PCR结果显示随着PSP浓度及作用时间的增加,PSP对HSV-1病毒DNA的抑制作用明显增强,具有良好的剂量和时效关系。提示PSP抗HSV-1及HSV-2病毒作用的机制与抑制病毒吸附和感染细胞内病毒的生物合成有关。     

富硒螺旋藻中硒别藻蓝蛋白的纯化及其特性

从富硒螺旋藻(Se richSpirulina platensis,Se-SP)中分离纯化高纯度的含硒别藻蓝蛋白(Se-containingallophycocyanin,Se-APC)并观察其生化特性。羟基磷灰石和DEAE-52柱层析方法结合制备电泳技术纯化Se-APC;光谱扫描、Native-PAGE、SDS-PAGE和IEF方法鉴定Se-APC生化特性;2,3-DAN荧光光度法检测蛋白质中Se含量。结果发现3种高纯度Se-APC的光谱特征分别与APCI、APCII、APCIII吻合;电泳鉴定它们可能都是(αβ)3,α、β亚基分别为18.3和15.7 kDa,其pI值分别为:4.76、4.85和5.02;3种Se-APC中Se含量分别为316、273和408μg/g,Se-APC经0.5mol/L NaSCN解聚和β-巯基乙醇变性处理后,蛋白质中Se含量依次减低并趋于稳定。结果提示Se-SP中APC可结合Se,APC中Se含量与其分子聚态有关,亚基中含Se量稳定,可能是以共价键方式结合,Se-APC生物活性及硒在蛋白质中的结合位点值得深入研究。     

螺旋藻多糖抗柯萨奇B3病毒的体外实验研究

在体外进行了钝顶螺旋藻多糖(polysaccharides from Spirulina platensis,PSP)抗柯萨奇病毒B3(Coxsackie virus B3,CVB3)活性的研究.以不同剂量的PSP作用于病毒复制周期的各个环节,以病毒半数感染量(TCID50),细胞病变效应(CPE),蚀斑形成单位(PFU),MTT染色细胞保护率(MTT法)作为评价指标,判断PSP的抗病毒效果.结果表明PSP对Vero细胞毒性极低(TC50为1750μg/mL),对CVB3无直接灭活作用,PSP可干扰病毒向宿主细胞的吸附,其抗病毒生物合成的活性最高(IC50为5.26,TI为237.6),是阳性对照药病毒唑的3.95倍,但不影响病毒的释放.提示PSP抗病毒靶位可能在于抑制病毒吸附和感染细胞内病毒的生物合成.     

钝顶螺旋藻(Spirulina platensis)光系统Ⅰ的分离表征及稳定性

采用蔗糖密度梯度离心法对钝顶螺旋藻光合膜蛋白(PSI)进行分离纯化,并对其光谱学性质、热稳定性及光合放氧活性进行分析表征。结果发现,采用蔗糖密度精度离心法,可以成功分离出4条色素蛋白质复合体条带,其中最下层条带为完整的PSI三聚体,其每毫克叶绿素a光合放氧活性达到420μmol/h。当温度达到50℃左右时,分离得到的PSI在溶液开始变性失活。     

Isolation of Biopterin-α-glucoside from Spirulina (Arthrospira) platensis and Its Physiologic Function

A fluorescent substance was isolated from the cyanobacterium with a yield of 4.5 mg per 10 g of dried Spirulina (Arthrospira) platensis cells by gentle extraction and ethanol fractionation followed by column chromatography. The fluorescent substance, which has absorption maxima at 256 nm and 362 nm (pH 8.4), was identified as biopterin-α-glucoside by spectrophotometry and nuclear magnetic resonance spectroscopy. Biopterin-α-glucoside prevented decolorization of the photosynthetic pigments, chlorophyll a, phycocyanin, and carotenoids in photosynthetic vesicles of Spirulina platensis cells, by ultraviolet irradiation. Received June 23, 1998; accepted September 10, 1998.     

螺旋藻（Spirulina platensis）藻胆体在解离过程中荧光发射光谱和光能传递的研究

对螺旋藻（Ｓｐｉｒｕｌｉｎａｐｌａｔｅｎｓｉｓ）藻胆体在室温和７７Ｋ处于不同浓度磷缓冲溶液和不同解离时间的荧光发射光谱进行了研究。藻胆体在０．９ｍｏｌ／Ｌ磷酸缓冲溶液中,由于没有发生解离,光能传递效率高,在７７Ｋ荧光发射光谱中只有一个峰,位于６８７ｎｍ,属于别藻蓝蛋白－Ｂ。当藻胆体悬浮在０．３ｍｏｌ／Ｌ磷酸缓冲溶液中１分钟,７７Ｋ荧光光谱的主峰出现在６８４ｎｍ．又出现６５５ｎｍ和６６６ｎｍ荧光峰,它们依次属子Ｃ－藻蓝蛋白和别藻蓝蛋白。在２小时;６５５ｎｍ荧先峰成为主峰,６８４ｎｍ荧光峰为次峰,６６６ｎｍ荧光肩消失。这表明Ｃ－藻蓝蛋白所捕获的先能已不能传递给别藻蓝蛋白,但能传给别藻蓝蛋白－Ｂ。我们提出在螺旋藻藻胆体中存在两类Ｃ－藻蓝蛋白,一是与别藻蓝蛋白相连接,另一是与别藻蓝蛋白－Ｂ相连接。     

A potent anti-oxidant property: fluorescent recombinant α-phycocyanin of Spirulina

Aims:  To express and product a fluorescent antioxidant holo-α-phycocyanin (PC) of Spirulina platensis ( Sp ) with His-tag (rHHPC; recombinant holo-α-phycocyaninof Spirulina platensis with His-tag) in 5-l bench scale.
Methods and Results:  A vector harbouring two cassettes was constructed: cpcA along with cpcE - cpcF in one cassette; ho1 - pcyA in the other cassette. Lyases CpcE/F of Synechocystis sp. PCC6803 ( S6 ) could catalyse the 82 site Cys in apo-α-PC of Sp linking with bilin chromophores, and rHHPC was biosynthesized in Escherichia coli BL21. The constant feeding mode was adopted, and transformant reached the biomass of rHHPC up to 0·55 g l⁻¹ broth in 5-litre bench scale. rHHPC was purified by Ni²⁺ affinity column conveniently. The absorbance and the fluorescence emission spectra of rHHPC had λ_max at 621 and 650 nm, respectively. The IC₅₀ values of rHHPC were 277·5 ± 25·8 μ g ml⁻¹ against hydroxyl radicals and 20·8 ± 2·2  μ g ml⁻¹ against peroxyl radicals.
Conclusions:  Combinational biosynthesis of rHHPC was feasible, and the constant feeding mode was adopted to produce good yields of rHHPC. Fluorescent rHHPC with several unique qualitative and quantitative features was effective on scavenging hydroxyl and peroxyl radicals.
Significance and impact of the study:  A potent antioxidant rHHPC was co-expressed, produced and characterized for nutritional and pharmacological values, which would help to develop phycobiliproteins' applications in their fluorescent and biological activities.