Prevention and amelioration of erythrocyte instability observed under deficiency of vitamin B12 alone or combined with micronutrient limitation through dietary supplementation with Chlorella and Spirulina

Micronutrient rich microalgae, Chlorella and Spirulina, could be natural food supplements to overcome the micronutrient deficiency, increasingly recognised as a global health issue. In two independent experiments, the Spirulina and Chlorella were evaluated as prophylactic and ameliorative dietary supplements of vitamin B12. Erythrocyte stability (relative osmotic fragility and haemolysis percentage), haematological parameters, micronutrient deficiency (serum levels of iron, zinc), plasma vitamin B12 and vitamin B12 biomarker (methylmalonic acid) were analysed. The deficient groups receiving Spirulina and Chlorella as prophylactic dietary supplements showed a 1.34 to 1.41 folds increase in serum iron and a 2.13 to 2.19 folds increase in plasma vitamin B12, compared to B12 deficient group. Supplementation of Spirulina to ameliorate vitamin B12 deficiency combined with micronutrient limitation showed an increase of 1.14 folds and 1.2 folds in serum iron and zinc respectively and 1.51 folds in plasma vitamin B12 compared to the deficient group. The relative osmotic fragility of erythrocytes in deficient experimental animals was 17 to 45% higher compared to the control. The osmotic fragility and deformation in the morphology of erythrocytes observed under vitamin B12 deficiency, alone or in combination with micronutrient limitation, were prevented and ameliorated on dietary supplementation with the microalgal biomass.

Harvesting of Chlorella sorokiniana BR001 cultivated in a low-nitrogen medium using different techniques / Colheita de Chlorella sorokiniana BR001 cultivada em um meio com baixo teor de nitrogênio utilizando diferentes técnicas

ABSTRACT: The harvesting process is a current challenge for the commercial production of microalgae because the biomass is diluted in the culture medium. Several methods have been proposed to harvest microalgae cells, but there is not a consensus about the optimum method for such application. Herein, the methods based on sedimentation, flocculation, and centrifugation were evaluated on the recovery of Chlorella sorokiniana BR001 cultivated in a low-nitrogen medium. C. sorokiniana BR001 was cultivated using a low-nitrogen medium to trigger the accumulation of neutral lipids and neutral carbohydrates. The biomass of C. sorokiniana BR001 cultivated in a low-nitrogen medium showed a total lipid content of 1.9 times higher (23.8 ± 4.5%) when compared to the biomass produced in a high-nitrogen medium (12.3 ± 1.2%). In addition, the biomass of the BR001 strain cultivated in a low-nitrogen medium showed a high content of neutral carbohydrates (52.1 ± 1.5%). The natural sedimentation-based process was evaluated using a sedimentation column, and it was concluded that C. sorokiniana BR001 is a non-flocculent strain. Therefore, it was evaluated the effect of different concentrations of ferric sulfate (0.005 to 1 g L-1) or aluminum sulfate (0.025 to 0.83 g L-1) on the flocculation process of C. sorokiniana BR001, but high doses of flocculant agents were required for an efficient harvest of biomass. It was evaluated the centrifugation at low speed (300 to 3,000 g) as well, and it was possible to conclude that this process was the most adequate to harvest the non-flocculent strain C. sorokiniana BR001.

RESUMO: O processo de colheita é um desafio atual para a produção comercial de microalgas porque a biomassa é diluída no meio de cultivo. Diversos métodos têm sido propostos para coletar células de microalgas, porém não existe um consenso sobre um método ótimo para tal aplicação. Neste estudo, métodos baseados em sedimentação, floculação e centrifugação foram avaliados na recuperação de Chlorella sorokiniana BR001 cultivada em um meio com baixo teor de nitrogênio. C. sorokiniana BR001 foi cultivada em um meio com baixo teor de nitrogênio para induzir ao acúmulo de lipídeos e carboidratos neutros. A biomassa de C. sorokiniana BR001 cultivada em um meio com baixo teor de nitrogênio apresentou um teor de lipídeos 1,9 vezes superior (23,8 ± 4,5%), quando comparada à biomassa produzida em um meio com alto teor de nitrogênio (12,3 ± 1,2%). Adicionalmente, a biomassa da linhagem BR001 cultivada em um meio com baixo teor de nitrogênio apresentou alto teor de carboidratos neutros (52,1 ± 1,5%). O processo baseado em sedimentação natural foi avaliado utilizando uma coluna de sedimentação e concluiu-se que C. sorokiniana BR001 é uma linhagem não floculante. Portanto, o efeito de diferentes concentrações de sulfato férrico (0,005 a 1 g L-1) ou sulfato de alumínio (0,025 a 0,83 g L-1) foram avaliados no processo de floculação de C. sorokiniana BR001, mas altas doses de floculantes foram necessárias para uma colheita de biomassa eficiente. Também foi avaliada a centrifugação em baixa velocidade (300 a 3.000 g), e foi possível concluir que este processo constituiu o mais adequado para a colheita da linhagem não floculante C. sorokiniana BR001.

Biofuel production potential of indigenous isolates of Scenedesmus sp. from lake water in Pakistan

Aims@#This paper presents the report on biodiesel and biogas production at a laboratory scale from Scenedesmus strain.@*Methodology and results@#Previously isolated and identified Scenedesmus were grown in 10 Liter flask using BG-11 media at 16 h light and 8 h dark cycle. Oven-dried biomass (20 g) from 16-day-old culture of Scenedesmus was finely grounded and subjected to lipids extraction by chloroform-methanol-NaCl mixture. Microalgal lipids (6 mL) were subjected to transesterification by using NaOH leading to the production of 5 mL biodiesel and 4 mL of glycerin. Biodiesel was rich in methyl esters of linoleic acid, phosphorothioc acid and dodecanoic acid, as shown by gas chromatography-mass spectrometry (GC-MS) analysis. Oven-dried microalgae (2 g) without lipid extraction and leftover biomass (2 g) after lipid extraction were subject to biogas production through anaerobic digestion. Biogas (34, 27 and 19 mL) were recorded respectively in oven-dried whole biomass; lipid extracted biomass and control over a period of 15 days of anaerobic digestion.@*Conclusion, significance and impact of study@#It was concluded that water bodies are rich in diverse algae, especially Scenedesmus sp., and this algae can be cultured to produce biodiesel and biogas. But the lipid accumulation potential of microalgae requires special treatment and lipid extraction methods are not up to the mark, which is a major bottleneck in biofuel production from microalgae.

Tactic movement of microalgae and its application in targeted transport: a review / 生物工程学报

Microalgae are a group of photosynthetic microorganisms, which have the general characteristics of plants such as photosynthesis, and some species have the ability of movement which resembles animals. Recently, it was reported that microalgae cells can be engineered to precisely deliver medicine-particles and other goods in microfluidic chips. These studies showed great application potential in biomedical treatment and pharmacodynamic analysis, which have become one of the current research hotspots. However, these developments have been rarely reviewed. Here, we summarized the advances in manageable movement exemplified by a model microalgae Chlamydomonas reinhardtii based on its characteristics of chemotaxis, phototaxis, and magnetotaxis. The bottlenecks and prospects in the application of microalgae-based tactic movement were also discussed. This review might be useful for rational design and modification of microalgal manageable movement to achieve targeted transport in medical and other fields.

Advances in the co-culture of microalgae with other microorganisms and applications / 生物工程学报

Intense utilization and mining of fossil fuels for energy production have resulted in environmental pollution and climate change. Compared to fossil fuels, microalgae is considered as a promising candidate for biodiesel production due to its fast growth rate, high lipid content and no occupying arable land. However, monocultural microalgae bear high cost of harvesting, and are prone to contamination, making them incompetent compared with traditional renewable energy sources. Co-culture system induces self-flocculation, which may reduce the cost of microalgae harvesting and the possibility of contamination. In addition, the productivity of lipid and high-value by-products are higher in co-culture system. Therefore, co-culture system represents an economic, energy saving, and efficient technology. This review aims to highlight the advances in the co-culture system, including the mechanisms of interactions between microalgae and other microorganisms, the factors affecting the lipid production of co-culture, and the potential applications of co-culture system. Finally, the prospects and challenges to algal co-culture systems were also discussed.

Producción de astaxantina bajo factores de estrés utilizando un biorreactor a escala de laboratorio de 5 L / Astaxanthin production under stress factors using a 5L laboratory scale bioreactor / Astaxanthin production under stress factors using a 5L laboratory scale bioreactor

Resumen Introducción. Haematococcus pluvialis es una microalga que produce astaxantina, un beta-caroteno y antioxidante muy usado en la industria. Para obtener una mayor producción de astaxantina se planteó como objetivo utilizar diferentes factores de estrés, en un biorreactor a escala de laboratorio de 5 litros. Metodología. Se cultivó la microalga en el medio RM, pH 6,8, temperatura 20±2°C, aire filtrado, iluminación con lámparas blancas 20h luz/4h oscuridad, irradianza 70 μE m-2s-1, diferentes concentraciones de acetato de sodio y cloruro de sodio. Se determinó crecimiento celular, cambios morfológicos y cuantificación de astaxantina y clorofila por espectrofotometría. Se realizó un análisis estadístico utilizando ANOVA (95%). Resultados. Utilizando 0,299 mg/L de acetato de sodio se obtuvo un crecimiento celular de 2,0 x 104 Cel/mL y una concentración de astaxantina de 2,530 μg/mL, mientras que con 1,6 mg/L de acetato de sodio el crecimiento celular fue de 3,5 x 104 Cel/mL y una concentración de astaxantina de 1,9 μg/ml. El tratamiento al cual se le adicionó 1,6 g/L de acetato de sodio y 6,4 g/L de cloruro de sodio presentó la mayor producción astaxantina 7,3 μg/ml. El tratamiento con acetato de sodio 0,320 g/L + cloruro de sodio 1,28 g/L presentó el mayor crecimiento celular con 1,64x105 células/ml. Conclusión. Esta investigación destaca la importancia de cultivar inicialmente la microalga utilizando el biorreactor Tecferm de 5 litros y después de su fase exponencial someterla a factores de estrés con acetato de sodio y cloruro de sodio lográndose así la mayor producción de astaxantina 7,325 μg/ml.

Abstract Introduction. Haematococcuspluvialis is a microalgae that produces astaxanthin, a beta-carotene and antioxidant widely used in industry. In order to obtain a higher production of astaxanthin, the objective was to use different stress factors, in a 5-liter laboratory-scale bioreactor. Methodology. The microalgae was cultivated in the RM medium, pH 6.8, temperature 20 ± 2°C, filtered air, illumination with white lamps 20h light/4h darkness, irradiance 70 μE m-2s-1, different concentrations of sodium acetate and chloride of sodium. Cell growth, morphological changes and quantification of astaxanthin and chlorophyll were determined by spectrophotometry. Statistical analysis was performed using ANOVA (95%). Results. Using 0.299 mg/L of sodium acetate a cell growth of 2.0 x 104 Cel/mL and an astaxanthin concentration of 2.530 μg/mL were obtained, while with 1.6 mg/L of sodium acetate the cell growth It was 3.5 x 104 Cel/mL and an astaxanthin concentration of 1.9 μg/mL. The treatment to which 1.6 g L of sodium acetate and 6.4 g/L of sodium chloride were added showed the highest astaxanthin production, 7.3 μg/ml. Treatment with 0.320 g/L sodium acetate + 1.28 g/L sodium chloride showed the highest cell growth with 1.64x105 cells/ml. Conclusion. This research highlights the importance of initially cultivating the microalgae using the 5-liter Tecferm bioreactor and, after its exponential phase, subjecting it to stress factors with sodium acetate and sodium chloride, thus achieving the highest production of 7.325 μg/ml astaxanthin.

Evaluation of the operational conditions in the production and morphology of Chlorella sp / Avaliação das condições operacionais na produção e morfologia de Chlorella sp

Abstract It was evaluated the effect of operational conditions in the production of Chlorella sp. after its selection from genus Chlorella sp., Scenedesmus sp., Nannochloris sp., Tetraselmis sp. and Dunaliella salina. Microalgae were inoculated in drinking water with addition of NPK fertilizer (N 24%, P 24%, K 18%), at a concentration of 0.5 g/L, agitation of 150 rpm, temperature 25 °C, light intensity of 1680 lumens at a color temperature of 6400K, without pH control for 8 days. The cellular concentrations obtained were 3.72x107 (Chlorella sp.), 1.36x107 (Scenedesmus sp.), 3.55x107 (Tetraselmis sp.), 5.74x107 (Nannochloris sp.) and 3.45x106 (Dunaliella salina), where the microalgae Chlorella sp., shows invasive capacity in drinking water cultivations. Applying the 2n-p fractional factorial design concept for the elemental composition of the microalgae and the cellular morphology, it was obtained 44.33% of C, 7.09% of H, 8.53% of N and 0.84% ​​of S for the Chlorella sp.

Resumo Foi avaliado o efeito das condições operacionais na produção de Chlorella sp. após a seleção do gênero Chlorella sp., Scenedesmus sp., Nannochloris sp., Tetraselmis sp. e Dunaliella salina. Microalgas foram inoculadas em água potável com adição de fertilizante NPK (N 24%, P 24% e K 18%), na concentração de 0,5 g/L, agitação de 150 rpm, temperatura de 25 °C, intensidade luminosa de 1.680 lúmens para uma temperatura de cor de 6.400 K, sem controle de pH por 8 dias. As concentrações celulares obtidas foram de 3,72 x 107 (Chlorella sp.), 1,36 x 107 (Scenedesmus sp.), 3,55 x 107 (Tetraselmis sp.), 5,74 x 107 (Nannochloris sp.) e 3,45 x 106 (Dunaliella salina), em que a microalga Chlorella sp. mostrou capacidade invasiva em cultivos de água potável. Aplicando o conceito de projeto fatorial fracionado 2n-p para a composição elementar da microalga e a morfologia celular, foram obtidos 44,33% de C, 7,09% de H, 8,53% de N e 0,84% de S para a Chlorella sp.

Ecología funcional de las algas perifíticas en el Chocó colombiano: limitación de recursos, competencia y variables ambientales / Functional ecology of periphytic algae in the Colombian Chocó: resource limitations, competition, and environmental variables

Introducción: El conocimiento de las comunidades perifíticas es importante, dada su participación en la producción primaria de los ambientes fluviales; además, el perifiton es una valiosa comunidad bioindicadora. No obstante, hasta la fecha es poco lo que se conoce sobre la ecología funcional de esta comunidad en los ríos colombianos. Objetivo: En este trabajo se buscó caracterizar algunos aspectos funcionales de la comunidad de ficoperifiton de cuatro sistemas lóticos de la Reserva Natural La Planada, ubicada en el departamento de Nariño, Colombia. Métodos: Durante mayo de 2019, en cada río se establecieron entre uno y tres sitios de muestreo, en los cuales se midieron las características hidrológicas y fisicoquímicas y se determinó la composición taxonómica y algunos rasgos funcionales de las comunidades de algas perifíticas. Se calcularon la media ponderada comunitaria (MPC) y la varianza ponderada comunitaria (VPC) de estos rasgos y se exploró su relación con las variables abióticas mediante regresiones, correlaciones y análisis de correspondencia canónica (ACC). Resultados: Se registraron 59 géneros de algas, de los cuales a 47 se les midieron los rasgos funcionales. La MPC del rasgo exoesqueleto silíceo fue estadísticamente mayor en la quebrada El Tejón. La MPC y la VPC de los demás rasgos no varió entre ríos, pero en algunos de ellos la presencia de mucílago y la organización en filamentos tendió a ser mayor. La amplia fluctuación de la VPC de todos los rasgos funcionales parece señalar que estas comunidades ficoperifíticas no tienen limitaciones de recursos, la competencia es reducida y las especies tienden a ser funcionalmente diferentes. Las variables ambientales con mayor influencia fueron el caudal, la mineralización del agua, el pH y la transparencia. La presencia de mucílago se asoció con la dureza del agua y el predominio de algas filamentosas con la transparencia; el pH influyó positivamente la relación superficie/volumen (S/V). Conclusiones: Este estudio constituye una línea base que permitirá evaluar cambios en las comunidades de algas bentónicas ante posibles intervenciones y brindar pautas para eventuales acciones de restauración de los sistemas fluviales de esta región de importancia mundial por su elevada biodiversidad.

Introduction: Knowledge on the periphytic community is essential because of its central role in river primary production. Also, periphyton is a valuable bioindicator of the community. However, to the date, little is known about the functional ecology of these communities in Colombian rivers. Objective: This work sought to characterize functional aspects of the phycoperiphytic community of four lotic systems of the La Planada Natural Reserve, located in the Department of Nariño, Colombia. Methods: In May 2019, between one and three sampling sites were established in each river. Hydrological and physicochemical variables were measured. Periphyton was sample to determine the taxonomic composition of the benthic algae as well as some functional traits. From these traits, the community weighted mean (CWM) and community weighted variance (CWV) were calculated, and their relation with abiotic variables was explored using regressions, correlations, and a canonical correspondence analysis (CCA). Results: 59 genera of algae were recorded, from which 47 had its functional traits measured. The CWM of the siliceous exoskeleton trait was statistically higher in El Tejón creek. The other traits had similar CWM and CWV values in all rivers. However, the traits of the presence of mucilage and organization in filaments showed predominance in some streams. The fluctuating data of CWV in all rivers seem to indicate that these phycoperiphytic communities have no resource limitations, competition is low, and species tend to be functionally different. The environmental variables with the greatest influence were flow, water mineralization, pH, and water transparency. The hardness of the water and the presence of mucilage were associated, while the predominance of filamentous algae was related to transparency; pH positively influenced the surface/volume ratio (S/V). Conclusions: This study represents a baseline that will allow evaluating changes in the benthic algae communities in the face of possible interventions and providing guidelines for eventual actions to restore the river systems of this important region due to its high biodiversity.

Advances in Microalgal Research in Brazil

Abstract Microalgae research has attracted interest worldwide and in order to advance algal biotechnology in Brazil, government has been funding several projects. In the last 10 years, two main funds were provided by the National Council of Scientific and Technological Development (CNPq) agency to researchers in Brazil, who study the potential uses of microalgae for biomass, bioproducts and biofuels production. These funded projects addressed aspects of algal strain identification, development of algal cultivation techniques, designing photobioreactors and raceway ponds, modeling harvesting and dewatering process, maximizing biomass and oil productivities, characterizing chemical composition with different extractions systems and determining physiochemical properties of biodiesel. This review presents the state of art of algal research conducted by Brazilian institutions. Special attention is given to the recent progress on microalgal cultivation, high-value products extracted from microalgae and potential biofuels production. This review may serve as a policy instrument for planning next steps for algal research in Brazil as well as for attracting attention from international researchers who work with microalgae and would like to pursue a future partnership on algal research with Brazilian research institutions.

Research progress on the biomedical application of microalgae / 浙江大学学报·医学版

Microalgae is an easy-to-obtain natural biological material with many varieties and abundant natural reserves. Microalgae are rich in natural fluorescein, which can be used as a contrast agent for fluorescence imaging and photoacoustic imaging for medical imaging. With its active surface, microalgae can effectively adsorb functional molecules, metal elements, etc., and have good application prospects in the field of drug delivery. Microalgae can generate oxygen through photosynthesis to increase local oxygen concentration, reverse local hypoxia to enhance the efficacy of hypoxic tumors and promote wound healing. In addition, microalgae have good biocompatibility, and different administration methods have no obvious toxicity. This paper reviews the research progress on the biomedical application of microalgae in bioimaging, drug delivery, hypoxic tumor treatment, wound healing.

Effect of algal antimicrobials on selected aquatic pathogens and characterization of bioactive compounds

Marine microalgae have been reported as an excellent source of bioactive compounds. The present study analyzesthe existence of bioactive phytochemicals and their efficacy in antimicrobial activity against aquatic pathogens.The antimicrobial compounds were extracted from three marine microalgae, namely Chlorella sp., Pavlova sp., andChaetoceros sp., and Pavlova sp. showed a broad spectrum of activity. Pavlova sp. extracts were tested against theselected aquatic pathogens, such as Vibrio harveyi, Vibrio parahaemolyticus, Pseudomonas aeroginosa, Aeromonashydrophila, and Staphylococcus aureus, and the result showed the inhibiting activity against aquatic pathogens. Theminimum inhibitory concentration and minimum bactericidal concentration, cytotoxic assay, and mode of actionwere also studied. The effective five crude extracts were purified by column chromatography and tested against thepathogens; then, the active fraction was partially characterized by Fourier transform infrared (FTIR) analysis. TheFTIR result suggested the presence of bioactive groups, such as amines, alkane, carboxylic acid, sulfoxide, alcohol,boron, etc. From the five extracts, two active extracts were selected and subjected to TLC (Thin layer chromatography).The cytotoxic activity (LD-50) indicates that the compound may be safe and effective for clinical trial. Finally, thealgal cytotoxic assay concluded that the isolated compound can also be used as an algicide to control algal blooms.This study proves that Pavlova sp. is an excellent source of pharmacologically active resourceful algae and showseffective activity against aquatic pathogens.

Primer reporte de Lemmermanniella uliginosa (Synechococcaceae, Cyanobacteria) en América del sur, y primer reporte del género para Perú / First report of Lemmermanniella uliginosa (Synechococcaceae, Cyanobacteria) in South America, and the first record of the genus from Peru

Resumen El presente trabajo reporta por primera vez para el Perú a la cianobacteria bentónica Lemmermanniella uliginosa, identificada en muestras de perifiton y sedimentos bentónicos procedentes del humedal de Caucato en el distrito de San Clemente, departamento de Ica. Además, se registra por primera vez al género Lemmermanniella para el país. Se discuten aspectos morfo-taxonómicos de la especie comparándola con poblaciones reportadas para otras localidades en zonas tropicales.

Abstract This work presents the first record of Lemmermmanniella uliginosa from Peru based on periphyton and sediment samples from Caucato wetland (San Clemente district, Ica department). Furthermore, the genus Lemmermmanniella is recorded for the first time for Peru. Morpho-taxonomic comparison with other populations reported in tropical regions is discussed.

An efficient algae cell wall disruption methodology for recovery of intact chloroplasts from microalgae

The microalgal cell wall breakage has been identified as complex phenomenon which is highly dependent onthe nature and composition of cell wall. A detailed analysis of plastids and their function requires the breakingopen of cell without any damage to cellular components. To develop a rapid and universal methodology forcell wall breakage, liquid nitrogen crushing, sonication, enzymatic lysis, and homogenization procedures wereapplied to various microalgal species. Homogenization-based procedure for the isolation of intact chloroplastwas found to be universal for all algal species under the study. The isolated chloroplasts were subjected tochloroplast integrity analysis. The intact chloroplast exhibited a positive maximum quantum yield and Fv/Fm values ranging from 0.1 to 0.4 as measured by pulse amplitude modulation fluorometry and was found tobe suitable for further downstream applications such as isolation of protein–pigment complexes involved inphotosynthetic O2 evolution. The developed methodology is a quick and efficient technique for the isolation ofintact chloroplasts across different genera of microalgae by employing minor changes in the base protocol as aspecies-specific characteristic

Optimization of physical parameters for the growth and lipid production in Nannochloropsis gaditana (Lubian, 1982)

Microalgae produce a wide range of compounds including pigments, protein, starch, and lipids, which havebeen extensively used for various applications. In the current scenario, microalgal lipids are considered as apromising source for the production of next-generation bioenergy, and a huge productivity is needed to meet thedemand. Thus, to increase the production of biomass and lipid content, physical conditions play an importantrole and necessary to be optimized. The present study made such an attempt to optimize the physical factors forthe growth and production of lipid from Nannochloropsis gaditana. The study aimed to determine the effect ofphysical parameters such as pH, temperature, light intensity, and salinity. The results showed that the maximumgrowth rate of the N. gaditana was noticed in the salinity of 25 ppt, pH of 8, temperature of 25°C, and 2,000 luxof light intensity. The highest lipid content of the N. gaditana was noticed in the salinity of 30 ppt, pH of 8, andtemperature of 30°C with 2,000 lux light intensity. After optimization, above 40% of lipid yield was obtained,and it can be effectively utilized in bioenergy production.

Fatty Acid Biosynthesis from Chlorella in Autotrophic and Mixotrophic Cultivation

Abstract Microalgae are photosynthetic microorganisms whose composition and biomass production can be influenced by manipulating the cultivation conditions employed. However, few studies have evaluated the effects of various cultivation conditions in autotrophic and mixotrophic conditions. The present work aimed to evaluate the effects of cultivation conditions on the cell growth and biosynthesis of fatty acids (FAs) by microalgae of the genus Chlorella in autotrophic and mixotrophic cultivation. Evaluation of the effects of the conditions was performed using an experimental design methodology. The highest values of maximum biomass concentration (Xmax) and maximum biomass productivity (Pmax) were obtained in autotrophic cultures. Palmitic acid was the FA obtained at the highest concentration in both cultivation modes. The concentrations of polyunsaturated FAs (PUFAs) ranged from 12.2 to 41.2% in autotrophic cultures and from 11 to 34.3% in the mixotrophic cultures. The variables photoperiod and sodium bicarbonate concentration showed the greatest influence on the Xmax, Pmax, and PUFA concentration in autotrophic and mixotrophic cultivations, respectively. This study verified that the selection of conditions and mode of cultivation contribute to the production of microalgal biomass and FA biosynthesis.

Transformation of Brewery Subproducts into Valuable Biomass Using Mixotrophic Culture of Chlorella pyrenoidosa and Associated Bacteria

Abstract To develop a biorefinery concept applied in the brewery industry, Chlorella pyrenoidosa and a consortium of associated bacteria were cultivated mixotrophically in a continuous photobioreactor using brewery low-value subproducts as an integrative process. Beer production residues were biochemically characterized to assess the most promising options to be used as a nutrient source for microalgal cultivation. Due to its physical and chemical properties, pre-treated weak wort was used to prepare an organic complex culture medium for microalgal biotransformation. Filtration and nitrogen supplementation were necessary to improve nutrient removal and biomass productivity. Maximal removal of nitrate and phosphate obtained were 90% and 100% respectively. Depending on operation conditions, total carbohydrates depuration ranged from 50 - 80%. The initial concentration of total carbohydrates of the weak wort must be adjusted to 2 - 4g/L to maintain a stable equilibrium between microalgal and bacterial growth. The biochemical composition of produced biomass varied depending on the cultivation conditions as well as on its final use. Upon continuous mixotrophic conditions evaluated in this study, C. pyrenoidosa was composed mainly of carbohydrates and protein.

Crecimiento poblacional de Macrothrix spinosa alimentada con Chlorella sp / Population growth of Macrothrix spinosa fed with Chlorella sp / Crescimento populacional de Macrothrix spinosa alimentado com Chlorella sp

Resumen El zooplancton es considerado como un alimento de gran importancia para las larvas de los peces por su excelente perfil nutricional. La mayor dificultad en el cultivo del zooplancton, en especial de cladóceros, es la susceptibilidad al alimento que consumen, pues deficiencias en los nutrientes influyen significativamente en su producción. Por tanto, el estudio de la partícula alimenticia en cantidad y calidad óptima es necesario para potencializar la producción. En la Piscícola San Silvestre S.A. se evaluó el efecto del alimento sobre las variables productivas del cladócero Macrothrix spinosa con fotoperiodo 12:12 luz: oscuridad y aireación constante en 8 unidades experimentales con volumen de 2,5 L. Los organismos, en densidad inicial de 2 org/mL, se alimentaron con la microalga Chlorella sp, previamente cultivada en dos medios de cultivo: (T1) Chlorella sp. cultivada con F/2 de Guillard y (T2) Chlorella sp. cultivada con Nutrifoliar®. Fueron determinados los parámetros poblacionales: densidad máxima (Dm), tasa instantánea de crecimiento (K), tiempo de duplicación (Td) y rendimiento (R). Diariamente se registró la temperatura (25,86±0,36 °C), pH (7,58±0,32) y OD (5,74±0,56 mg/L). La mayor Dm fue 27,38±0,08 org/mL en T1 (P>0,05). Mayor K, menor Td y mayor R se registraron en T1 (0,24±0,00, 2,84±0,04 días y 2,50±0,01 org/mL respectivamente) (P>0,05). Los resultados sugieren que M. spinosa, alimentada con la microalga Chlorella sp. cultivada con F/2 de Guillard, alcanza mejor desempeño poblacional en cultivo.

Abstract Zooplankton is considered a food of great importance for fish larvae because of its excellent nutritional profile. The greatest difficulty in the culture of zooplankton, especially cladocerans, is the susceptibility to the food they consume, since deficiencies in the nutrients significantly influence their production. Therefore, the study of the food particle in optimal quantity and quality is necessary to potentiate production. In the Piscícola San Silvestre S.A, the effect of the food on the productive variables of the cladoceran Macrothrix spinosa with photoperiod 12:12 light: dark and constant aeration in 8 experimental units with volume of 2,5 liters was evaluated. The organisms, in initial density of 2 clad / mL, were fed with the microalga Chlorella sp, previously cultivated in two culture media: (T1) Chlorella sp. cultivated with Guillard's F/2 and (T2) Chlorella sp. grown with Nutrifoliar®. The population parameters were determined: maximum density (Dm), instantaneous growth rate (K), doubling time (Td) and yield (R). The temperature was recorded daily (25,86±0,36 °C), pH (7,58±0,32) and OD (5,74±0,56 mg/L). The highest Dm was 27,38±0,08 org/mL in T1 (P>0,05). Higher K, lower Td and higher R were recorded in T1 (0,24±0,00, 2,84±0,04 days and 2,50±0,01 org/mL respectively) (P>0,05). The results suggest that M. spinosa fed with the microalga Chlorella sp. cultivated with Guillard's F / 2, achieves better population performance in culture.

Resumo O zooplâncton é considerado um alimento de grande importância para as larvas de peixes, devido ao seu excelente perfil nutricional. A maior dificultade na cultura do zooplâncton, especialmente dos cladóceros, é a suscetibilidade aos alimentos que consomem; uma vez que deficiências nos nutrientes influenciam significativamente sua produção. Portanto, o estudo da partícula alimentar em quantidade e qualidade ótimas é necessário para potencializar a produção. Na Piscícola San Silvestre S.A, foi avaliado o efeito do alimento sobre as variáveis produtivas do cladoceran Macrothrix spinosa com fotoperíodo 12:12 luz: escura e aeração constante em 8 unidades experimentais com volume de 2,5 litros. Os organismos em densidade inicial de 2 org/mL foram alimentados com a microalga Chlorella sp., previamente cultivada com dois meios de cultura: (T1) Chlorella sp. cultivada com F/2 de Guillard e (T2) Chlorella sp. cultivada com Nutrifoliar®. Os parâmetros populacionais foram determinados: densidade máxima (Dm), taxa de crescimento instantâneo (K), tempo de duplicação (Td) e rendimento (R). A temperatura foi registrada diariamente (25,86±0,36 °C), pH (7,58±0,32) e OD (5,74±0,56 mg/L). O maior Dm foi de 27,38±0,08 org/mL em T1 (P> 0,05). Maior K, menor Td e maior R foram registrados em T1 (0,24±0,00, 2,84±0,04 dias e 2,50±0,01 org/mL, respectivamente) (P>0,05). Os resultados sugerem que M. spinosa alimentada com a microalga Chlorella sp. cultivada com F/2 de Guillard, alcança melhor desempenho populacional em cultura.

Ácidos grasos en cepas de microalgas del Banco de Germoplasma de Organismos Acuáticos del Instituto del Mar del Perú (IMARPE)

Se determinó la composición de ácidos grasos de 54 cepas microalgales colectadas del Perú y mantenidas en el Banco de Germoplasma de Organismos Acuáticos (IMARPE) con la finalidad de determinar su uso nutricional en la acuicultura. Para ello se realizaron cultivos en un volumen de 50 mL y se determinaron los porcentajes relativos de ácidos grasos mediante transesterificación directa y cromatografía de gases. En el grupo Chlorophyta las microalgas que presentaron los mayores valores de porcentaje relativo de ácidos grasos fueron Chlamydomonas reinhardtii (16:0; 41.2%), Scenedesmus obtusus (18:1n-7; 33.6%), Acutodesmus dimorphus (18:1n-9; 37.1%), Desmodesmus armatus (18:3n-3; 32.2%) y Tetraselmis contracta (16:4n-3; 16.5%). En cambio en el grupo Bacillariophyta, los ácidos grasos más abundantes fueron 16:1n-7 en Chaetoceros didymus (20.2%), 18:4n-3 en Navicula sp. (28.3%) y EPA en Asterionellopsis sp. (31.5%). Por otro lado, en el grupo Dinophyta, todas las cepas superaron el 20% de DHA, en particular, la cepa de Akashiwo sanguinea presentó el mayor porcentaje relativo de este ácido graso (29.9%) y de los ácidos grasos 16:0 (24.8%) y EPA (16%). Se discute el uso de estas cepas según su contenido de ácidos grasos.

In This work, we determinate the fatty acids composition and their nutritional value in 54 microalgal strains, collected from Peru and stored in Banco de Germoplasma de Organismos Acuáticos (IMARPE). The cultures were grown to 50 mL and analyzed by direct transesterification and gas chromatography. In the Chlorophyta group, the microalgaes that present the highest relative percentage of fatty acids were Chlamydomonas reinhardtii (16:0; 41.2%), Scenedesmus obtusus (18:1n-7; 33.6%), Acutodesmus dimorphus (18:1n-9; 37.1%), Desmodesmus armatus (18:3n-3; 32.2%) and Tetraselmis contracta (16:4n-3; 16.5%). Moreover in the Bacillariophyta group, the most abundant fatty acids were 16:1n-7 in Chaetoceros didymus (20.2%), 18:4n-3 in Navicula sp. (28.3%) and EPA in Asterionellopsis sp. (31.5%). By the other hand, in the Dinophyta group, all strains exceed the 20% of DHA, in particular Akashiwo sanguinea, it was strain to have the highest percentage of this fatty acid (29.9%) in addition to 16: 0 (24.8%) and EPA (16%). We discussed uses of these strains is according to their fatty acids content.

Microalgae protoplasts isolation and fusion for biotechnology research / Aislamiento y fusión de protoplastos de microalgas para aplicaciones biotecnológicas

ABSTRACT Protoplasts are microbial or vegetable cells lacking a cell wall. These can be obtained from microalgae by an enzymatic hydrolysis process in the presence of an osmotic stabilizer. In general, protoplasts are experimentally useful in physiological, genetic and biochemical studies, so their acquisition and fusion will continue to be an active research area in modern biotechnology. The fusion of protoplasts in microalgae constitutes a tool for strain improvement because it allows both intra and interspecific genetic recombination, resulting in organisms with new or improved characteristics of industrial interest. In this review we briefly describe the methodology for obtaining protoplasts, as well as fusion methods and the main applications of microalgal platforms.

RESUMEN Los protoplastos son células microbianas o vegetales que carecen de pared celular. Estos pueden obtenerse a partir de microalgas por un proceso de hidrólisis enzimática en presencia de un estabilizador osmótico. En general, los protoplastos son experimentalmente útiles en estudios fisiológicos, genéticos y bioquímicos, por lo que su obtención y fusión continuarán siendo un área de investigación activa en la biotecnología moderna. La fusión de protoplastos en microalgas constituye una herramienta para el mejoramiento de cepas pues permite la recombinación genética intra e interespecífica, logrando así organismos con nuevas características de interés industrial. En esta revisión, describimos brevemente la metodología para obtener protoplastos, métodos de fusión y las principales aplicaciones de las plataformas basadas en microalgas.

Evaluación del periodo de llenado y evacuación intestinal de Brachionus calyciflorus alimentado con Chlorella sp / Evaluation of the period of filling and intestinal evacuation of Brachionus calyciflorus fed on Chlorella sp / Avaliação do período de enchimento e evacuação intestinal de Brachionus calyciflorus (Rotifera: Brachionidae) alimentado com Chlorella sp

Resumen Con el fin de determinar la viabilidad del rotífero de agua dulce Brachionus calyciflorus utilizado como alimento vivo en la fase de larvicultura de especies ícticas, se evaluó el periodo cronológico de llenado y evacuación intestinal, mediante la alimentación con diferentes concentraciones de microalga Chlorella sp. en estado condensado. Los tratamientos fueron, T1: 1,2×106 células/mL, T2: 5,2×106 células/mL, T3: 10,4×106 células/mL y T4: 15,4×106 células/mL, en una densidad de 40 rotíferos/mL para cada tratamiento. Se realizó análisis de imagen, se aplicó una prueba de varianza ANOVA y test múltiple de Tukey a los resultados donde se establecieron diferencias significativas entre los tratamientos (P≤0.05); las variables analizadas fueron: volumen del cuerpo, volumen del intestino, volumen intestinal expresado en porcentaje y tiempo de tránsito intestinal. Para el análisis morfométrico el rango de volumen del cuerpo fue de 0,7×106µm3a 2,6 ×106µm3. El tiempo mínimo de llenado y evacuación fue de 60 minutos. Los porcentajes intestinales en su máxima repleción para cada tratamiento fueron T1: 5,55%, T2:8,62% T3:10,53% y T4: 8,08%, en consecuencia, el tiempo idóneo para suministrar el rotífero B. calyciflorus como alimento vivo en larvicultura, es de 105 - 225 minutos, después de iniciado la ingesta de la microalga.

Abstract In order to determine the viability of the freshwater rotiferBrachionus calyciflorusused as alive food in the phase of larviculture of ictic species,there was evaluated the chronological period of filling and intestinal evacuation, by means of the supply with different concentrations of microalgae Chlorella sp. in condensed condition. The treatments were, T1: 1.2 × 106 cells / mL, T2: 5.2 × 106 cells / mL, T3: 10.4 × 106 cells / mL and T4: 15.4 × 106 cells / mL, all of them with a density of 40 for each treatment. Analysis of image was realized, and it was applied a test of variance ANOVA and Tukey›s multiple test to the results where significant differences between the treatments were established (P≤0.05); the variables analyzed were: volume of body, bowel volume, intestinal volume expressed in percentage and intestinal transit time. For morphometric analysis, the volume rank of the body was of 0,7×106 µm3 to 2,6 ×106 µm3. The minimum filling and evacuation time were 60 minutes. The intestinal percentages in their maximum repletion for each treatment were T1: 5.55%, T2: 8.62% T3: 10.53% and T4: 8.08%, consequently, the suitable time to supply the rotiferB. Calyciflorusas alive food in larviculture it is of 105 - 225 minutes, after initiated the ingestion of the microalgae.

Resumo A fim de determinar a viabilidade do rotífero de água doce Brachionus calyciflorus utilizado como alimento vivo na fase de larvicultura, foi avaliado o período cronológico de enchimento e evacuação intestinal através da alimentação com diferentes concentrações de microalga Chlorella sp. em estado condensado. Os tratamentos foram, T1: 1,2×106 células/mL, T2: 5,2×106 células/mL, T3: 10,4×106 células/mL e T4: 15,4×106 células/mL, numa densidade de 40 rotíferos/mL para cada tratamento. Foi realizado um analise de imagem e aplicado um teste de variância ANOVA e o teste múltiplo de Tukey aos resultados dos tratamentos onde foram estabelecidas diferenças significativas (P≤0.05); as variáveis analisadas foram: volume corporal, volume intestinal, volume intestinal expresso em porcentagem e tempo de trânsito intestinal. Para a análise morfométrica, a faixa de volume corporal foi de 0,7×106 µm3 a 2,6 ×106 µm3. O tempo mínimo de enchimento e evacuação foi de 60 minutos. As porcentagens intestinais em sua repleção máxima para cada tratamento foram T1: 5,55%, T2: 8,62% T3: 10,53% e T4: 8,08%. Em consequência, o tempo ideal para fornecer o rotífero B. calyciflorus como alimento vivo na larvicultura é de 105 - 225 minutos, após o início da ingesta da microalga.