Influence of Light Intensity and Photoperiod on the Photoautotrophic Growth and Lipid Content of the Microalgae Verrucodesmus verrucosus in a Photobioreactor (original) (raw)
Related papers
Journal of Applied Phycology, 2013
Microalgae are considered as a promising feedstock for biomass production. The selection of the most suitable species is based on several key parameters such as lipid and fatty acid productivity. In the present study, the growth of different microalgae strains was examined in freshwater media for photoautotrophs suited for large-scale applications to identify the most suitable medium for each species. In the optimal medium, Scenedesmus obliquus showed the highest biomass productivity measured as increase of cell dry weight (0.25 g cellu dry weight (CDW) L −1 day −1 ), while Botryococcus braunii showed the highest lipid and total fatty acid content (430 and 270 mg g −1 CDW, respectively) among the tested species. Regarding lipid and total fatty acid productivity, S. obliquus was the most lipid and total fatty acid productive strain with 41 and 18 mg L −1 day −1 during the exponential phase, respectively. Additionally, the proportion of saturated and monounsaturated fatty acids increased with duration of the incubation in S. obliquus, while polyunsaturated fatty acids decreased. These results nominate S. obliquus as a promising microalga in order to serve as a feedstock for renewable energy production.
Bioresource Technology, 2011
We describe a methodology to investigate the potential of given microalgae species for biodiesel production by characterizing their productivity in terms of both biomass and lipids. A multi-step approach was used: determination of biological needs for macronutrients (nitrate, phosphate and sulphate), determination of maximum biomass productivity (the ''light-limited" regime), scaling-up of biomass production in photobioreactors, including a theoretical framework to predict corresponding productivities, and investigation of how nitrate starvation protocol affects cell biochemical composition and triggers triacylglycerol (TAG) accumulation. The methodology was applied to two freshwater strains, Chlorella vulgaris and Neochloris oleoabundans, and one seawater diatom strain, Cylindrotheca closterium. The highest total lipid content was achieved with N. oleoabundans (25-37% of DW), while the highest TAG content was found in C. vulgaris (11-14% of DW). These two species showed similar TAG productivities.
2015
The application of microalgal oil for energy purposes continues to present a number of challenges, including the optimization of culture conditions. In this study, the two light intensities at 2.5 Klux and 5 Klux were used in light-dark cycles of 8:16, 16:8, 0:24 and 24:0 hour to investigate the effect of light intensity and photo period on biomass production and lipid productivities in microalgae, Chlorella vulgaris and Nannochloropsis sp. in view of optimizing the illumination level for biodiesel production through algal oil. Chlorella vulgaris and Nannochloropsis sp were cultured in Guillard and Rither`s f/2 media for 21 days and 14 days growth periods respectively in a laboratory scale closed experimental set-up. The cultures were aerated with mechanical aerators. Finally, cells were harvested by flocculation and dry weight and the percentage lipid content were estimated. Significantly higher average dry matter yield was observed when the cells cultured under 5 Klux light intens...
Energies
Microalgae are considered to be potentially attractive feedstocks for biodiesel production, mainly due to their fast growth rate and high oil content accumulated in their cells. In this study, the suitability for biofuel production was tested for Chlorella vulgaris, Chlorella fusca, Oocystis submarina, and Monoraphidium strain. The effect of nutrient limitation on microalgae biomass growth, lipid accumulation, ash content, fatty acid profile, and selected physico-chemical parameters of algal biodiesel were analysed. The study was carried out in vertical tubular photobioreactors of 100 L capacity. The highest biomass content at 100% medium dose was found for Monoraphidium 525 ± 29 mg·L−1. A 50% reduction of nutrients in the culture medium decreased the biomass content by 23% for O. submarina, 19% for Monoraphidium, 13% for C. vulgaris and 9% for C. fusca strain. Nutrient limitation increased lipid production and reduced ash content in microalgal cells. The highest values were observe...
Microorganisms
The development of clean and renewable energy sources is currently one of the most important challenges facing the world. Although research interests in algae-based energy have been increasing in the last decade, only a small percentage of the bewildering diversity exhibited by microalgae has been investigated for biodiesel production. In this work, seven strains of green microalgae belonging to the genera Scenedesmus, Tetradesmus and Desmodesmus were grown in liquid medium with or without a nitrogen (N) source—at two different irradiances (120 ± 20 and 200 ± 20 μmol photons m−2 s−1)—to evaluate biomass production and FAME (fatty acid methyl esters) content for biodiesel production. The strains of Tetradesmus obliquus and Desmodesmus abundans grown in N-deprived medium showed the highest FAME content (22.0% and 34.6%, respectively); lipid profile characterization highlighted the abundance of saturated FAME (as C16:0 and C18:0) that favors better viscosity (flow properties) and appli...
Energies
Optimization of the fatty acid profile in microalgae is one of the key strategies for obtaining valuable products and sustainable biofuels. Light intensity and light regimes exert an impact on the growth and metabolic process in microalgae. The objective of the present investigations was to assess the effect of light intensity and continuous light vs. photoperiod conditions on the growth and changes in the biomass composition in Eustigmatos magnus, with a focus on bioactive molecules such as lipids and fatty acids. The highest daily productivity of Eustigmatos magnus biomass and lipid yields were detected at continuous illumination and at the highest intensity of light. The results show that the content and composition of fatty acids was influenced by the culture conditions. The biomass of Eustigmatos magnus contained the highest concentrations of polyunsaturated fatty acids in the pphotoperiod conditions with the highest light intensity. This study shows that Eustigmatos magnus has...
Microalgae are discussed as an alternative source for the production of biofuels. The lipid content compared to cultivation time of used species is the main reason for any choice of a special strain. This paper reviews more analytical data of 38 screened microalgae strains. After the cultivation period, total content of lipids was analysed. The extracted fatty acids were quantified as fatty acid methyl esters by GC analysis. The amino acids were analysed by HPLC. Chlorella sp., Chlorella saccharophila, Chlorella minutissima and Chlorella vulgaris were identified as species with the highest productivity of fatty acids relevant to transesterification reactions. The components were mainly linoleic acid, palmitic acid and oleic acid. To increase productivity of highly saturated fatty acids, cultivation parameters light intensity and temperature were varied. In this manner, the ideal conditions for biodiesel production were defined in this publication.
Bioresource Technology , 2016
h i g h l i g h t s Phosphate, pH and light intensities have marked effect on the FA profile of alga. 60 mg/L phosphate has favoured high biomass and lipid concentration. Illumination of 6000 lux was suitable for biomass and lipid production. Biomass increased at pH 8, whereas pH 6 favoured lipid content. Favourable phosphate, pH and light conditions resulted in good fuel properties. a b s t r a c t The present study dealt with biomass, lipid concentration, fatty acid profile and biodiesel properties of microalga Scenedesmus abundans under different phosphate concentrations, pH and light intensities, one at a time. Among different phosphate concentrations, higher biomass (770.10 ± 11.0 mg/L) and lipid concentration (176.87 ± 4.6 mg/L) were at the concentration of 60 mg/L. Light intensity at 6000 lux yielded higher biomass and lipid concentration of 742.0 ± 9.7 and 243.15 ± 9.1 mg/L, respectively. The biomass (769.0 ± 12.3 mg/L) and lipid (179.47 ± 5.5 mg/L) concentration were highest at pH 8 and pH 6, respectively. All the culture treatments showed marked effect on the fatty acid profile and biodiesel properties of the extracted oil. FAME derived biodiesel properties were compared with European biodiesel standards (EN 14214), Indian biodiesel standards (IS 15607) and American biodiesel standards (ASTM D 6751-08) to assess the suitability of algal oil as biodiesel feedstock.
African Journal of Biotechnology
Microalgae are a promising alternative source to produce biofuels and bio-products, as they consume carbon dioxide to grow, multiply quickly, and can be cultivated in domestic and industrial wastewater. The efficiency of microalgae-based biodiesel industry depends on the selection of appropriate strains with best lipid content yields and adequate fatty acids composition. The aim of this study was to select a potential microalga strain for lipid production by bioprospecting and screening lipid productivity and fatty acid compositions of some local microalgae isolated from different water bodies located in the region of Agadir, Morocco and cultivated in homemade photobioreactors. For this purpose, four freshwater microalgae Parachlorella kessleri, Cyclotella species, Chlorella species and Closterium species were isolated and cultivated. Lipid extraction was carried out using Soxhlet and fatty acids profiling was performed using Gas Chromatography. The highest lipid content was obtained with a diatom microalga Cyclotella spp. (33 wt%) after 15 days of residence time. The investigated strains produced high amount of oleic acid (41-54%) followed by linoleic (18-33%), palmitic (13-23%) and stearic acid (4-12%), respectively. Variations in lipid production and fatty acids composition as responses to changes in residence times form another important factor to feedstock selection for biofuel production.
2020
The main purpose of this review is to evaluate the design of several photobioreactor (PBR) systems with the microalgae cultures and the quality of the microalgae species related to the production of lipid for biodiesel. In general, microalgae cultivation is divided into two systems: open pond system (unstirred, circular, raceway) and closed system (flat-panel, horizontal tube, helical tube, vertical tube, stirred tank, big bag), made by transparent and waterproof materials, and able to provide an ideal cultivation environment for photosynthetic microalgae. There are some issues to be considered in microalgae cultivation systems such as modelling by simulation, data collecting, mixing, illumination, gas exchange, availability of the nutritions and the cost of the system. Most common microalgae for PBRs and their lipid percentages as follows: Chlorella ellipsoidea %84, Schizochytrium sp . %77, Botryococcus braunii %74, Nitzschia sp. %51 Chlorella protothecoides %51 and Neochloris oleo...