Cyanobacterium Spirulina Platensis Research Articles

Fabrication of silver nanoparticles employing the cyanobacterium Spirulina platensis and its bactericidal effect against opportunistic nosocomial pathogens of the respiratory tract

There are several biomimetic approaches to synthesize silver nanoparticles (AgNPs). The present investigation describes a solitary method for the synthesis of AgNPs in one-pot by means of Spirulina platensis extract. The as-formed AgNPs were characterized by the following methods. Initially, UV–Vis spectrophotometer indicated a distinctive surface plasmon resonance peak for AgNPs at 417 nm. Fourier Transform Infrared Spectroscopy (FTIR) indicated the particle capping by organics of the extract. Transmission electron microscopy (TEM) confirmed the formation of spherical AgNPs with an average size of 13 nm. X-ray diffraction (XRD) analysis elucidated the crystalline nature of AgNPs. The average particle size and polydispersity index (PDI) of AgNPs were 74.8 nm and 0.285 as recorded by dynamic light scattering (DLS). Thermal gravimetric analysis (TGA) indicated the thermal stability of AgNPs at elevated temperatures. Among all other active components of the algal extract, the proteins could play a major role in reduction, stabilization and encapsulation of AgNPs. Further, the antibacterial activity was assessed against seven different species of bacterial pathogens present in respiratory tract. The AgNPs were found promising against the test pathogens.

Phycocyanobilin reduces brain injury after endothelin-1- induced focal cerebral ischaemia.

Pharmacological therapies for interrupting biochemical events of the ischaemic cascade and protecting against stroke in humans are as yet unavailable. Up to now, the neuroprotective activity in cerebral ischaemia of phycocyanobilin (PCB), a tetrapyrrolic natural antioxidant, has not been fully examined. Here, we evaluated if PCB protects PC12 neuronal cells against oxygen and glucose deprivation plus reperfusion, and its protective effects in a rat model of endothelin-1-induced focal brain ischaemia. PCB was purified from the cyanobacteria Spirulina platensis and characterized by spectrophotometric, liquid and gas chromatography and mass spectrometry techniques. In Wistar rats, PCB at 50, 100 and 200μg/kg or phosphate-buffered saline (vehicle) was administered intraperitoneally at equal subdoses in a therapeutic schedule (30minutes, 1, 3 and 6hours after the surgery). Brain expression of myelin basic protein (MBP) and the enzyme CNPase was determined by immunoelectron microscopy. PCB was obtained with high purity (>95%) and the absence of solvent contaminants and was able to ameliorate PC12 cell ischaemic injury. PCB treatment significantly decreased brain infarct volume, limited the exploratory behaviour impairment and preserved viable cortical neurons in ischaemic rats in a dose-dependent manner, compared to the vehicle group. Furthermore, PCB at high doses restored the MBP and CNPase expression levels in ischaemic rats. An improved PCB purification method from its natural source is reported, obtaining PCB that is suitable for pharmacological trials showing neuroprotective effects against experimental ischaemic stroke. Therefore, PCB could be a therapeutic pharmacological alternative for ischaemic stroke patients.

Carbamazepine toxicity and its co-metabolic removal by the cyanobacteria Spirulina platensis

Bioremediation of pharmaceutical-contaminated wastewater using microalgae has attracted increasing attention. Cyanobacteria, which are important prokaryotic microalgae, are widely distributed in different water environments, and have the advantages of simple culture and a fast growth rate. However, studies on either the toxicity of pharmaceutical contaminants (PhCs) to cyanobacteria or the removal of PhCs by cyanobacteria are scarce. In this study, carbamazepine (CBZ) and Spirulina platensis were selected as model PhCs and cyanobacteria, respectively. CBZ (>1 mg/L) had toxicity effects on S. platensis, showing maximal growth inhibition (34.0%) at 100 mg/L after 10 days of cultivation. At CBZ < 25 mg/L, S. platensis showed a trend similar to that of eukaryotic microalgae in increasing superoxide dismutase and catalase activities and content of chlorophylls, carotenoids, carbohydrates, and lipids. These results indicated that S. platensis had a similar protective mechanism to CBZ toxicity as that of the eukaryotic microalgae. Increasing CBZ concentration (50–100 mg/L) significantly decreased these biochemical characteristics and photosynthetic activity owing to the serious damage of the structure and function of S. platensis. However, with increasing cultivation time, the growth and photosynthetic activity of S. platensis recovered from the toxicity of CBZ. S. platensis showed a maximum of 30.97 ± 1.30% removal of CBZ (1 mg/L), mainly through biodegradation. Addition of 0.3 mg/L glucose enhanced this removal efficiency to 50.13 ± 2.51% via co-metabolism. These findings indicated that S. platensis can be used for the removal of CBZ or other PhCs from wastewater.

Growth and heavy metals accumulation by Spirulina platensis biomass from multicomponent copper containing synthetic effluents during repeated cultivation cycles

The metal bioaccumulation as well as biochemical changes in cyanobacterium Spirulina platensis biomass at its growth in multicomponent copper containing synthetic effluents during repeated cultivation cycle was investigated. It was demonstrated high capacity of metal accumulation by spirulina biomass from multicomponent systems, containing copper ions in concentration range 2.5–10 mg/L, along with iron, nickel and zinc. In systems with copper ions concentration 2.5 mg/L and 5 mg/L spirulina acted as a renewable biologic sorbent due to its ability to keep high metal accumulation capacity during 2–3 cultivation cycles. Capacity of renewable accumulator was ensured by maintenance of balance between spirulina biochemical components and expressed by moderate reduction of proteins content and optimal level of lipids content.

Gauging the acceptance and the attitudes of rural workers in the semiarid region of northeastern Brazil concerning the artisanal production and consumption of Spirulina platensis

Alternative foods that could diminish traditional nutritional deficits in human populations through new processes and new materials have been investigated in numerous recent publications. Within this context, the cyanobacterium Spirulina platensis has attracted a good deal of attention due to its high protein content and the presence of polyunsaturated fatty acids, pigments, salts, and vitamins. Seventy-five rural workers from the municipality of Frei Martinho, semiarid region of Paraíba State, Brazil. Participated in the present research that evaluated the acceptability of S. platensis as a food supplement. We evaluated their attitudes in terms of the possibility of cultivating that microalgae, if they would be open to dietary changes (innovative attitudes) or refractory to them (conservative attitudes), their attitudes towards possible artisanal cultivation of S. platensis, Laboratory cultures were prepared using synthetic media and the microalgae biomass was used for producing cakes, juices, and cookies; “in natura” or dried materials were also tested for acceptability, as well as their inclination to buy products based on Spirulina. The observed acceptability indices of were higher than expected (70%) for all of the attributes evaluated (appearance, odor, and texture) in three different presentations (“in natura”, dry, and incorporated into foods), except for the variable of odor in the “in natura” form (66.12%). In terms of intentions to buy, 88% of the interviewees confirmed that they would buy supplemented products if they were available. The attitude tests showed a consistent internal positive view of Spirulina, indicating that the agricultural workers tested were open to technological innovations.

The use of vermicompost in cultivation and production of Spirulina platensis

The cyanobacterium Spirulina platensis is quite spread all over the world due to its high nutritional value. It has been used as protein source and vitamin supplement in healthy diet, in aquaculture and fisheries. Cyanobacterium Spirulina is capable to grow in various kinds of culture media. Furthermore, decomposed organic and inorganic nutrients media have been proven to be good source of culture medium for Spirulina by many researchers. In this work, S. platensis was cultivated using dry vermicompost from fish sludge (VCFS) or cow manure (VCCM). 100 g of dry vermicompost from each source (VCFS/VCCM) collected and compared with Aiba and Ogawa liquid medium which was used as culture medium. The results obtained showed that the highest protein and chlorophyll a ratio of S. platensis were observed in the biomass harvested from T2 (VCCM) and T3 (Aiba and Ogawa liquid medium). The highest dried S. platensis biomass was harvested from T2 (VCCM) while the lowest came from T1 (VCFS). The chemical composition ( as % of dry weight) revealed that (VCCM) was higher in total phosphorus, total nitrogen and organic matter than (VCFS).

Metal ions removal from different type of industrial effluents using Spirulina platensis biomass

The biomass of the cyanobacterium Spirulina platensis was used for metal removal from four industrial effluents with different chemical composition. The process of metal bioaccumulation (alive biomass) and biosorption (dry biomass) was studied at the native effluents pH as well as the pH 9.5. Metal uptake by S. platensis biomass was determined by means of neutron activation analysis (NNA). The obtained results show different affinity of biomass to metals presented in effluents. The results of this study have indicated that S. platensis is a very good candidate for the removal of heavy metals from complex industrial effluents.

SIMULTANEOUS EFFECTS OF Cd(II) AND Pb(II) IONS AND γ-IRRADIATION ON STABILITY OF Spirulina platensis

Effect of toxic metal ions Cd(II) and Pb(II) on cyanobacterium (blue-green algae) Spirulina platensis intact cells have been studied with optical and differential scanning microcalorimetry (DSC) methods after 7.2 kGy 137 Cs gamma irradiation and without irradiation. It is shown that the addition of metal ions causes a decrease in optical absorption spectra band intensities. In the case of irradiation, the absorption band intensity decreases higher than without irradiation. The binding constant of Pb(II) with Spirulina platensis is calculated for nutrition medium with pH 9.2. DSC data show that Cd(II) and Pb(II) ions do not change the integral heat of absorption (Δ H m ) that equals to 24.6 J g -1 . In the case of irradiation, the DSC melting curve profile changes significantly and Δ H m decreases two times, which indicates that 50 % of proteins are denaturated. The DSC method also gives a possibility to evaluate C-phycocyanin content from deconvoluted heat absorption peak at 50 °C, which equals to 35.5 %. In case of irradiated wet mass, sub-cultured wet mass, and wet mass re-irradiated with the same dose, contents of Spirulina platensis ingredients – C-phycocyanin, chlorophyll, and carotenoids – increase as a result of the simultaneous effect of the metal ions and irradiation.

Biosorption of Re(VII) from Batch Solutions and Industrial Effluents by Cyanobacteria Spirulina platensis

The potential of Spirulina platensis biomass for rhenium ions removal from both batch solutions and industrial effluents is evaluated. The effect of pH, contact time, initial metal concentration, and the temperature of biosorbent treatment on the biosorption process is investigated. The maximum biosorption capacity of 142.9 mg g−1 rhenium is achieved at pH 2, sorbent dosage 0.05 g, and temperature of biosorbent treatment 30 °C. The equilibrium data are well fitted by Langmuir and Freundlich adsorption isotherm models (R2 = 0.99), while the pseudo‐second order kinetic model (R2 &gt; 0.99) is found to describe better the kinetic data. Fourier‐transform infrared (FTIR) spectra shows that rhenium biosorption takes place through two mechanisms: ionic interactions of perrhenate anions with amide and amino‐groups and/or binding to organic functional groups of the cell surface. The rhenium bound to the biomass can be effectively stripped using NH4OH (8%) and the biomass is effectively used for three sorption–desorption cycles. In the case of industrial effluents, S. platensis biomass shows relatively high rhenium removal efficiency (51–55%). S. platensis biomass can be efficiently applied for rhenium removal from industrial effluents.

Therapeutic effect of the alkaloid extract of the cyanobacterium Spirulina platensis on the lipid profile of hypercholesterolemic male rabbits.

The authors' objectives are to investigate the therapeutic effect of alkaloid extract of cyanobacteria Spirulina platensis on the lipid profile of hypercholesterolemic male rabbits and to identify the active compounds in the alkaloid extract. Male rabbits were divided into four groups of six animals. The intact rabbits in the first group served as a negative control. The second group served as a positive control (hypercholesterolemic rabbits). Over a 4-week period, hypercholesterolemic rabbits in the third group received a low dose of alkaloid extract (33mg/kg), and the hypercholesterolemic rabbits in the fourth group received a high dose (66mg/kg). The results revealed that both doses of alkaloid extract significantly decreased levels of cholesterol, triglycerides, low-density lipoproteins (LDL), and very low-density lipoproteins (VLDL) when compared to the control group, whereas the high-density lipoproteins (HDL) increased significantly compared to the control group. The active compounds in the alkaloid extract were identified using GC-mass. The most abundant compounds found in the extract were 1-(+)-ascorbic acid 2,6-dihexadecanoate, 9,12-octadecadienoic acid (Z, Z)-, hexadecanoic acid, 2-hydroxy-1- (hydroxymethyl) ethyl ester, and gamolenic acid.

Different characteristics of C-phycocyanin (C-PC) in two strains of the extremophilic Galdieria phlegrea

To date, the main source for phycocyanin production is the thermophilic cyanobacterium Spirulina platensis, although latest researches are exploring the possibility to exploit the thermoacidophilic Cyanidiophyceae (Rhodophyta) to this purpose. Galdieria phlegrea is a polyextremophilic red alga belonging to Cyanidiophyceae, colonizing, along with G. sulphuraria, acidic and thermal environments and distinguishable from this latter on the base of molecular and ecophysiological traits. In the present paper, a characterization of C-phycocyanin from two strains of G. phlegrea with different geographic provenance (Phlegrean Fields Naples, Italy; Diyadin, Turkey) was provided under autotrophic and heterotrophic conditions. The results showed different optimal pHs and thermostability between the strains and between autotrophic and heterotrophic cells. What is intriguing, a pre-heating at 70 °C of heterotrophic cells from the Italian strain resulted in a highly heat-resistant of C-phycocyanin. We hypothesized that the different features of this pigment, currently widely used for various applicative purposes, are related to the habitat from which the microalga comes from.

Comparative Study of Lanthanum, Vanadium, and Uranium Bioremoval Using Different Types of Microorganisms

Wastewater, containing vanadium, uranium, and lanthanum are produced by mining, nuclear, and other industries. Bacteria Pseudomonas putida, Halomonas mono, and cyanobacterium Spirulina platensis were used for lanthanum, vanadium, and uranium, removal from aqueous solutions by means of biosorption and bioreduction processes. A rapid rate of metal adsorption was observed within the first 5–15 min of the reaction. The pseudo-first-order model was found to correlate well with the experimental data. Bacteria show higher metal biosorption in comparison with cyanobacteria. The strong involvement of carboxyl, hydroxyl, carboxyl, and amide groups in studied metal binding was ascertained by FT-IR spectroscopy. Bioreduction studies carried out with Pseudomonas putida and Halomonas mono cells showed highness of metal reduction in alkaline conditions, resulting in the bioreduction of 69 and 85% of vanadate ions and 48 and 64% of uranyl ions, respectively. Using geochemical modeling, the insoluble metal phases were determined.

An attempt to induce an immunomodulatory effect in rowers with spirulina extract

BackgroundThe aim of this study was to analyze the response of selected components of the immune system in rowers to maximal physical exercise, and to verify if this response can be modulated by supplementation with spirulina (cyanobacterium Spirulina platensis).MethodThe double-blind study included 19 members of the Polish Rowing Team. The subjects were randomly assigned to the supplemented group (n = 10), receiving 1500 mg of spirulina extract for 6 weeks, or to the placebo group (n = 9). The participants performed a 2000-m test on a rowing ergometer at the beginning (1st examination) and at the end of the supplementation period (2nd examination). Blood samples were obtained from the antecubital vein prior to each exercise test, 1 min after completing the test, and after a 24-h recovery period. Subpopulations of T regulatory lymphocytes (Tregs) [CD4+/CD25+/CD127-], cytotoxic lymphocytes (CTLs) [CD8+/TCRαβ+], natural killer (NK) cells [CD3-/CD16+/CD56+] and TCRδγ-positive (Tδγ) cells were determined by means of flow cytometry.ResultsOn the 2nd examination, athletes from the supplemented group showed neither a post-exercise increase in Treg count nor a post-recovery decrease in Tδγ cell count (both observed in the placebo group), and presented with significantly lower values of Treg/CTL prior to and after the exercise. During the same examination, rowers from the placebo group showed a significant post-recovery increase in Treg/(NK + Tδγ + CTL) ratio, which was absent in the supplemented group.ConclusionThe results of this study imply that supplementation with spirulina extract may protect athletes against a deficit in immune function (especially, anti-infectious function) associated with strenuous exercise, and may cause a beneficial shift in “overtraining threshold” preventing a radical deterioration of immunity.

Effects of oral supplementation with Spirulina and Chlorella on growth and digestive health in piglets around weaning

Weaning of piglets is associated with important changes in gut structure and function resulting from stressful events such as separation from the sow, moving to a new facility and dietary transition from a liquid to a solid feed. This may result in post-weaning diarrhoea and a decrease in feed intake and growth. In humans, the cyanobacterium Spirulina platensis (SP) and the freshwater microalga Chlorella vulgaris (CV) are known for their beneficial health effects. This study aimed to determine the effects of early oral administration of Spirulina and Chlorella in piglets on mucosal architecture and cytokine expression in the intestine around weaning, and consequences on growth performance and diarrhoea incidence. The experiment was conducted on 108 suckling piglets of 14 days of age (initial BW=4.9±0.7 kg) and weaned at 28 days of age (day 0). Animals received orally 385 mg/kg BW per day of SP or CV, or water (negative control (NC)) during 4 weeks from day −14 to day 14 and their growth performance was measured daily. After weaning, growth, feed intake and diarrhoea incidence were measured daily. Intestinal morphology and functionality were assessed at day −1, day 2, and day 14. During the suckling period, average daily gain (ADG) in SP piglets was higher, resulting in a higher weaning BW compared to NC and CV piglets (P<0.05). No significant difference between treatments was observed for ADG, average daily feed intake, and gain to feed (G : F) ratio after weaning, but the extent of growth retardation after weaning was the lowest in piglets supplemented with Chlorella (P<0.01). Supplementation with Spirulina reduced diarrhoea incidence by 50% from day 0 to day 14 (P<0.05). Mucosal architecture at the jejunum was unaffected by Spirulina or Chlorella administration (P>0.10). Shorter ileal villi were measured in SP and CV piglets than in NC piglets (P<0.05). Cytokine expression did not differ between treatments in response to weaning. At day 14, IL-8 expression in the ileum was higher in SP piglets, while IL-1β expression in the jejunum was higher in CV piglets (P<0.05). This study shows that Spirulina administration around weaning alleviates diarrhoea in weaned piglets, without marked modulation of local inflammation.

Composition and functional property of photosynthetic pigments under circadian rhythm in the cyanobacterium Spirulina platensis.

Circadian rhythm is an important endogenous biological signal for sustainable growth and development of cyanobacteria in natural ecosystems. Circadian effects of photosynthetically active radiation (PAR), ultraviolet-A (UV-A) and ultraviolet-B (UV-B) radiations on pigment composition have been studied in the cyanobacterium Spirulina platensis under light (L)/dark (D) oscillation with a combination of 4/20, 8/16, 12/12, 16/8, 20/4 and 24/24h time duration. Circadian exposure of PAR + UV-A (PA) and PAR + UV-A + UV-B (PAB) showed more than twofold decline in Chl a, total protein and phycocyanin (PC) in light phase and significant recovery was achieved in dark phase. The fluorescence emission wavelength of PC was shifted towards lower wavelengths in the light phase of PAB in comparison to P and PA whereas the same wavelength was retrieved in the dark phase. The production of free radicals was accelerated twofold in the light phase (24h L) whereas the same was retrieved to the level of control during the dark phase. Oxidatively induced damage was alleviated by antioxidative enzymes such as catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and ascorbate peroxidase (APX) in the light phase (0-24-h L) whereas the dark phase showed significant inhibition of the same enzymes. Similar characteristic inhibition of free radicals and recovery of PC was observed inside cellular filament after circadian rhythm of 24/24h (L/D). Circadian exposure of P, PA and PAB significantly altered the synthesis and recovery of pigments that could be crucial for optimization and sustainable production of photosynthetic products for human welfare.

Biosorption of lead ions by cyanobacteria Spirulina platensis: kinetics, equilibrium and thermodynamic study

Abstract The potential use of dry Spirulina platensis biomass to remove lead ions from aqueous solution was investigated. Effects of various parameters such as contact time, temperature, dosage of biosorbent, initial pH, and initial concentration of lead were investigated in the batch adsorption mode. The highest lead removal of 5.7 mg/g was obtained at pH 5, biomass dosage of 0.5 g, initial lead concentration of 60 mg/L. The Langmuir and Freundlich models fit the experimental data (R2 &gt; 0.99), while the kinetic data was best described using the pseudo second-order kinetic model (R2 &gt; 0.99). FTIR spectra indicated that the metal removal takes place through binding to OH, C=O and P=O groups. Lead was efficiently recovered from biomass by mineral acids, while using CH3COOH and NaOH as eluents the biomass maintained high biosorption capacity during three cycles. This study demonstrates the potential of using Spirulina platensis as biosorbent to remove lead from industrial wastewater.

In vitro activity of Spirulina platensis water extract against different Candida species isolated from vulvo-vaginal candidiasis cases.

The high incidence of vulvo-vaginal candidiasis, combined with the growing problems about azole resistance and toxicity of antifungal drugs, highlights the need for the development of new effective strategies for the treatment of this condition. In this context, natural compounds represent promising alternatives. The cyanobacterium Spirulina platensis, a blue-green alga, exhibits antimicrobial activities against several microorganisms. Nevertheless, only few data about the antifungal properties of Spirulina platensis are available and its potential toxic effects have not been largely investigated.The aim of this study was to evaluate the in vitro activity of a fully-characterized water extract of Spirulina platensis against 22 strains of Candida spp. Prior to considering its potential topical use, we both investigated whether the extract exerted target activities on guinea pig uterine smooth muscle, and the impact of Spirulina platensis on the dominant microorganisms of the vaginal microbiota (i.e., lactobacilli), in order to exclude possible adverse events. By means of a broth microdilution assay, we found that the microalga extract possesses good antifungal properties (MIC: 0.125–0.5 mg/ml), against all the Candida species with a fungicidal activity. At the concentrations active against candida, Spirulina platensis did not modify the spontaneous basic waves pattern of uterine myometrium as underlined by the absence of aberrant contractions, and did not affect the main health-promoting bacteria of the vaginal ecosystem. Finally, we evaluated the selectivity index of our extract by testing its cytotoxicity on three different cell lines and it showed values ranging between 2 and 16.Further in vivo studies are needed, in particular to evaluate the use of control-release formulations in order to maintain Spirulina platensis concentrations at anti-Candida active doses but below the toxic levels found in the present work.

Effect of Copper and Lead on Growth and Some Metabolic Activities of Cyanobacterium Spirulina platensis (Nordstedt)

TODAY the heavy metal pollution is one of the most important environmental problem, which causes in soil and aquatic environment. Biosorption is an innovative technology that employs biological materials to accumulate heavy metals from waste water through metabolic process or physicochemical pathways of uptake. We studied the metabolic responses of Spirulina platensis to the toxicity of two heavy metals,Cu2+ and Pb2+. The data show that the lower doses of metals had stimulatory effect on biomass of Spirulina platensis, whereas the higher doses were found to be inhibitory depending on the type of the metal. The inhibitory effect of copper upon growth parameters of Spirulina platensis was more pronounced than lead. The total protein content, chlorophyll content, total carbohydrate and the total free amino acids of the tested alga gradually decreased in a manner dependent on the metal concentration in the medium. Biosorption of algal biomass was found to be heavy metal concentrations and pH dependent, where Spirulina platensis accumulated the amount of Pb2+ more than Cu2+. Concerning the effect of different concentrations of Cu2+ and Pb2+ on photosynthetic O2 evolution, the results showed reduction in the amount of O2 evolved in response to increasing metals concentrations. On the other hand, the effect of the heavy metals on respiration showed that higher metals concentrations were inhibitory to O2 uptake by Spirulina platensis.

Contribution of microalgae-enriched fodder for the Nile tilapia to growth and resistance to infection with Aeromonas hydrophila

We studied the impact of using fodder enriched with the cyanobacterium Spirulina platensis or the green alga Chlorella vulgaris or a consortium containing both of them on growth, biochemistry profile and immune status of the Nile tilapia (Oreochromis niloticus) fish. A set of 240 males challenged with Aeromonas hydrophila one week before the end of 9weeks experimental period. The fodder supplemented with 15% (w/w) of Spirulina platensis, 15% of Chlorella vulgaris or 15% of their (1/1) mixture. Growth performance was measured all over 9weeks. Challenge test was performed by infection with the pathogen after 8weeks of growth. The serum total contents of protein, albumin, globulin, urea, creatinine and activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALK) and lactate dehydrogenase (LDH) were measured at 7days before and after the infection. The results revealed significant increases in body weight of the Chlorella and their mixture (Chlorella and Spirulina) treated groups compared with the untreated control and the only Spirulina treated ones (p≤0.05). Without infection, the serum total protein and serum globulin significantly increased by supplementation with the Spirulina, Chlorella and both compared to the uninfected control group. The serum albumin significantly decreased with Chlorella and the mixture supplementations. Lactate dehydrogenase (LDH) in the fish serum generally decreased with application of the enriched feed compared with the control. After infection, serum total protein and globulin significantly increased by the feed supplementations compared with the control group while the serum albumin insignificantly increased by supplementation with Chlorella and Spirulina. ALT, AST, ALK, LDH, urea and creatinine in the fish serum decreased with the microalgae additives compared with the control.

Investigation of in vitro digestibility of dietary microalga Chlorella vulgaris and cyanobacterium Spirulina platensis as a nutritional supplement

Microalgal proteins are promising sources for functional nutrition and a sustainable candidate for nutraceutical formulations. They also gain importance due to emerging focus on a healthy nutrition and increase in the number of chronic diseases. In this study, dried dietary species of microalga, Chlorella vulgaris, and cyanobacterium Spirulina platensis were hydrolyzed with pancreatin enzyme to obtain protein hydrolysates. The hydrolysis yield of biomass was 55.1±0.1 and 64.8±3.6% for C. vulgaris and S. platensis; respectively. Digestibility, as an indicator for dietary utilization, was also investigated. In vitro protein digestibility (IVPD) values depicted that cell wall structure due to the taxonomical differences affected both hydrolysis and digestibility yield of the crude biomass (p<0.05). Epithelial cells (Vero) maintained their viability around 70%, even in relatively higher concentrations of hydrolysates in the culture. The protein hydrolysates showed no any antimicrobial activities. This study clearly shows that the conventional protein sources in nutraceutical formulations such as soy, whey, and fish proteins can be replaced by enzymatic hydrolysates of microalgae, which shows elevated digestibility values as a sustainable and reliable source.