Evaluation of Marine Synechococcus for an Algal Biorefinery in Arid Regions (original) (raw)
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Production of microalgae as feedstock for biofuels must deal with a number of challenges including constraints imposed by local conditions. One solution is to use indigenous strains adapted to local climatic conditions. The present report describes the isolation, identification, and characterization of 32 microalgal strains from different ecological habitats: desert freshwater channels, northern region, and saline regions of Pakistan. The effects of temperature on algal growth rates, biomass productivity, and lipid content were determined through growth at 12, 20, and 35 °C for 15 days under 2% CO2 Responses to temperature varied among species with 20 °C being the optimum temperature in general, although, exceptionally, the best overall growth rate was found for strain S29 (0.311 d−1) at 12 °C. In some cases high biomass productivity was observed at 35 °C, and, depending upon the strain, the maximum lipid content was obtained at different temperatures, including 12 °C. Fatty acid me...
Oleo science
To investigate the potential of application of marine cyanobacterium for concurrent biomass production and ammonium removal, Synechococcus sp. VDW was cultured under different conditions in medium containing varying concentrations of NH4Cl. Response surface methodology (RSM) was then used to build a predictive model of the combined effects of independent variables (pH, inoculum size, ammonium concentration). At the optimum conditions of initial pH 7.4, inoculum size 0.17 (OD730) and ammonium concentration 10.5 mg L–1, the maximum ammonium removal and biomass productivity were about 95% and 34 mg L–1d–1, respectively, after seven days of cultivation. The result of fatty acid methyl ester (FAME) analysis showed that the major fatty acids were palmitic acid (C16:0), linoleic acid (C18:2 n6 cis), palmitoleic acid (C16:1) and oleic acid (C18:1 n9 cis), which accounted for more than 80% weight of total fatty acids. Further, analysis of neutral lipid accumulation using flow cytometry revealed that the mean of the fluorescence intensity increased under optimal conditions. These results indicate that Synechococcus sp. VDW has the potential for use for concurrent water treatment and production of biomass that can be applied as biofuel feedstock.
Microalgae can grow effectively on various wastewaters, including those generated in aquaculture as a result of operation of hatcheries and farming systems. These organisms are able to remove pollutants from their growth environment, while the biomass produced can be further exploited. Such biomass contains lipids rich in polyunsaturated fatty acids and other substantial nutrients and can be used as a live feed in shrimp farming or in fisheries, i.e. as live feed for zooplankton or as fish feed supplement after enzymatic and/or chemical treatment. In the current work, a shrimp farm wastewater (SFW) with high nutrient (P, N) concentrations was used as growth medium for six newly isolated marine microalgae strains from Saudi Arabian coastal waters, including Chlorella sp., Dunaliella sp., Nannochloropsis sp., Navicula sp. (two strains) and Tetraselmis sp.. The growth yields and kinetics parameters were compared to those obtained in synthetic f/2 medium. Among these strains, Navicula sp. (both strains) and Tetra-selmis sp. were able to grow well on SFW, producing high lipid quantities (especially Navicula sp. 1) containing polyunsaturated fatty acids, including eicosapentaenoic acid. However, microalgae lipids produced in SFW medium were in general more saturated than those produced in f/2 medium. It seems that several desaturases, of both the C16 and C18 group, and probably the C16:0 elongase, were inhibited in SFW medium modifying accordingly the fatty acid profile. Considering the overall physiological behavior of the strains, including biomass yields and fatty acid composition, we conclude that SFW can be valorized in a sustainable way for microalgae production in fisheries.
The Potential of Marine Microalgae for the Production of Food, Feed, and Fuel (3F)
Fermentation
Whole-cell microalgae biomass and their specific metabolites are excellent sources of renewable and alternative feedstock for various products. In most cases, the content and quality of whole-cell biomass or specific microalgal metabolites could be produced by both fresh and marine microalgae strains. However, a large water footprint for freshwater microalgae strain is a big concern, especially if the biomass is intended for non-food applications. Therefore, if any marine microalgae could produce biomass of desired quality, it would have a competitive edge over freshwater microalgae. Apart from biofuels, recently, microalgal biomass has gained considerable attention as food ingredients for both humans and animals and feedstock for different bulk chemicals. In this regard, several technologies are being developed to utilize marine microalgae in the production of food, feed, and biofuels. Nevertheless, the production of suitable and cheap biomass feedstock using marine microalgae has ...
Critical reviews in biotechnology, 2014
Despite the great interest in microalgae as a potential source of biofuel to substitute for fossil fuels, little information is available on the effects of bacterial symbionts in mass algal cultivation systems. The bacterial communities associated with microalgae are a crucial factor in the process of microalgal biomass and lipid production and may stimulate or inhibit growth of biofuel-producing microalgae. In addition, we discuss here the potential use of bacteria to harvest biofuel-producing microalgae. We propose that aggregation of microalgae by bacteria to achieve >90% reductions in volume followed by centrifugation could be an economic approach for harvesting of biofuel-producing microalgae. Our aims in this review are to promote understanding of the effects of bacterial communities on microalgae and draw attention to the importance of this topic in the microalgal biofuel field.
Environmental Technology, 2013
Microalgae hold promise for the production of sustainable replacement of fossil fuels due to their high growth rates, ability to grow on non-arable land and their high content, under the proper conditions, of high energy compounds that can be relatively easily chemically converted to fuels using existing technology. However, projected large-scale algal production raises a number of sustainability concerns concerning land use, net energy return, water use and nutrient supply. The state-of-the-art of algal production of biofuels is presented with emphasis on some possible avenues to provide answers to the sustainability questions that have been raised. Here, issues concerning algal strains and supply of nutrients for large-scale production are discussed. Since sustainability concerns necessitate the use of wastewaters for supply of bulk nutrients, emphasis is placed on the composition and suitability of different wastewater streams. At the same time, algal cultivation has proven useful in waste treatment processes, and thus this aspect is also treated in some detail.
Journal of Marine Science and Engineering, 2019
The aim of the study was to explore the possibility of bioremediation of oil refinery wastewaters by the cyanobacterium Synechococcus sp. MK568070, isolated from the Adriatic Sea. The potential of biomass and lipid production was explored upon cultivation on oil refinery wastewater with excess CO2 after the removal of nutrients. The strain grew well in a wide range of salinities and ammonium concentrations, and was further tested on the wastewater from local oil refinery plant of various N-composition. Growth experiment under optimized conditions was used to analyze the lipid, carbohydrate and protein dynamics. The biomass yield was highly dependent on nutrient source and concentration, salinity and CO2 addition. Highest biomass yield was 767 mg/L of dry weight. Towards the end of the experiment the decline in carbohydrate to 18.9% is visible, whereas at the same point lipids, in particular saturated fatty acid methyl esters (FAME), started to accumulate within the cells. The conten...
Biomass and Lipid Production Potential of Economically Important Marine Microalgal Strains
International Journal of Current Microbiology and Applied Sciences, 2022
Four marine microalgal strains viz. Pavlova sp. ABT 102, Chromulina sp. ABT 103, Thalassiosira sp. AMS 5 and Chlorella sp. AMS 6 were tested for their biomass and lipid productivities through bench-scale studies to assess their potential for production of value added products. Among the four different marine microalgal strains Pavlova sp. ABT 102 isolate showed maximum volumetric biomass productivity of 0.048 g L-1d-1 followed by Chlorella sp. AMS 6 (0.035 g L-1d-1), Thalassiosira sp. AMS 5 (0.021 g L-1d-1) and Chromulina sp. ABT 103 (0.019 g L-1d-1). The highest volumetric lipid productivity was recorded by Chromulina sp. ABT 103 (11.12 mg L-1d-1) followed by Pavlova sp. ABT 102 (10.65 mg L-1d-1), Thalassiosira sp. AMS 5 (8.77 mg L-1d-1) and Chlorella sp. AMS 6 (7.73 mg L-1d-1). Among four algal strains, Chlorella sp. AMS 6 could effectively utilise sodium bicarbonate as an external inorganic carbon source in the growth medium. It was found that the addition of inorganic carbon sou...
Journal of Cleaner Production, 2018
Microalgae can grow effectively on various wastewaters, including those generated in aquaculture as a result of operation of hatcheries and farming systems. These organisms are able to remove pollutants from their growth environment, while the biomass produced can be further exploited. Such biomass contains lipids rich in polyunsaturated fatty acids and other substantial nutrients and can be used as a live feed in shrimp farming or in fisheries, i.e. as live feed for zooplankton or as fish feed supplement after enzymatic and/or chemical treatment. In the current work, a shrimp farm wastewater (SFW) with high nutrient (P, N) concentrations was used as growth medium for six newly isolated marine microalgae strains from Saudi Arabian coastal waters, including Chlorella sp., Dunaliella sp., Nannochloropsis sp., Navicula sp. (two strains) and Tetraselmis sp.. The growth yields and kinetics parameters were compared to those obtained in synthetic f/2 medium. Among these strains, Navicula sp. (both strains) and Tetraselmis sp. were able to grow well on SFW, producing high lipid quantities (especially Navicula sp. 1) containing polyunsaturated fatty acids, including eicosapentaenoic acid. However, microalgae lipids produced in SFW medium were in general more saturated than those produced in f/2 medium. It seems that several desaturases, of both the C16 and C18 group, and probably the C16:0 elongase, were inhibited in SFW medium modifying accordingly the fatty acid profile. Considering the overall physiological behavior of the strains, including biomass yields and fatty acid composition, we conclude that SFW can be valorized in a sustainable way for microalgae production in fisheries. Highlights: • The shrimp farm wastewater (SFW) can be considered as growth medium for microalgae. • Six newly isolated strains were cultivated in SFW. • Biomass and lipid yields in SFW were comparable to those obtained in f/2 medium. • Desaturases involved in polyunsaturated fatty acid synthesis maybe inhibited in SFW medium.
2021
Energy-storage metabolites such as neutral lipids and carbohydrates are valuable compounds for liquid biofuel production. The aim of this work is to elucidate the main biological responses of two algae species known for their effective energy-rich compound accumulation in nitrogen limitation and day–night cycles: Nannochloropsis gaditana, a seawater species, and Parachlorella kessleri, a freshwater species. Lipid and carbohydrate production are investigated, as well as cell resistance to mechanical disruption for energy-rich compound release. Nitrogen-depleted N. gaditana showed only a low consumption of energy-storage molecules with a non-significant preference for neutral lipids (TAG) and carbohydrates in day–night cycles. However, it did accumulate significantly fewer carbohydrates than P. kessleri. Following this, the highest levels of productivity for N. gaditana in chemostat cultures at four levels of nitrogen limitation were found to be 3.4 and 2.2 × 10−3 kg/m2·d for carbohyd...