scholarly journals Assessment of microalgal ACCase and rbcl gene expression as a function of nutrient and metal stress

2017 ◽  
Author(s):  
◽  
Poonam Singh
Keyword(s):  
Large Scale ◽  
Scale Up ◽  
Biomass Productivity ◽  
Photosynthetic Performance ◽  
Lipid Productivity ◽  
Biodiesel Production ◽  
Rbcl Gene ◽  
Limited Condition ◽  
Bg11 Medium ◽  
Microalgal Biodiesel

Microalgae are considered to be a potential feedstock for biodiesel production. However, the main concern with regard to the large scale microalgal biodiesel production process is its competence and economic viability. The commercial realization of microalgal biodiesel production requires substantial impetus towards development of efficient strategies to improve lipid yields upstream. Nitrogen (N) and phosphorus (P) stress during cultivation are the widely used lipid accumulation strategies for microalgae. However, these individual nutrient stress strategies are associated with compromised biomass productivity which hampers overall lipid productivity. Lipid enhancement strategies based on light, temperature and CO2 are associated with technological barriers for scale up and incur additional cost. Thus, the main aim of this study was to develop an integrated, easily applicable and scalable lipid enhancement strategy based on nutrients and metals such as N, P, iron (Fe), magnesium (Mg), calcium (Ca) and EDTA stress for selected indigenous microalgal strains. The effect of metal concentrations individually and in combination on microalgal lipids and biomass production is a scarcely exploited area. In this study, a novel approach involving individual as well as combined metals and EDTA stress under N and P limited conditions for lipid enhancement in microalgae was investigated. Microalgal growth physiology, photosynthetic performance, biochemical composition (lipid, carbohydrate and protein) and expression of selected key genes involved in photosynthesis (rbcL) and fatty acid biosynthesis (accD) were studied both under selected individual and combined stress conditions. Out of seven microalgal isolates obtained during the initial isolation and screening process, two strains were selected for lipid enhancement study based on their growth rates, biomass yields, lipid content and lipid productivities. The strains were later identified as Acutodesmus obliquus and Chlorella sorokiniana based on both morphological characteristics and phylogenetical analysis. The selected strains were thereafter subjected to different cultivation conditions involving varying metal, EDTA and nutrient stress conditions. A significant increase in lipid productivity was observed when the concentrations of Fe, Mg and EDTA were increased and Ca was decreased to degree in the N and P stress BG11 medium. For A. obliquus, a highest lipid productivity of 80.23 mgL-1d-1 was achieved with the developed strategy under limited N (750 mg L-1) condition which was 2.18 fold higher than BG11 medium and 1.89 fold higher than N limited condition alone. Similarly, for C. sorokiniana, highest lipid productivity of 77.03 mgL-1d-1 was achieved with the developed strategy under limited N (500 mgL-1) and P (10 mgL-1) which was 2.67 fold higher than BG11 medium and 2.35 fold higher than N and P limited condition alone. For both the microalgal strains, Fe was the most significant trace metal affecting their lipid productivity. These above observations were further confirmed through photosynthetic performance analysis and gene expression studies. At mid log phase, 6.38 and 5.15 fold increases in the expression levels of rbcL gene were observed under combined stress (OCMS+OE) as compared to the control (BG11) condition in A. obliquus and C. sorokiniana respectively. This also resulted in an increased expression level of accD gene involved in lipid biosynthesis to 10.25 fold and 9.79 fold in A. obliquus and C. sorokiniana respectively at late log phase. The results from expression studies of rbcL and accD genes were in compliance with biomass yields, photosynthetic performance, protein yield and lipid productivities for both the strains under different cultivating conditions. The universal applicability of the above strategy was confirmed by applying it to five other microalgae strains isolated in this study which resulted in considerable increase in their overall lipid productivity under optimized conditions. Attempts were made to scale up the lab scale study to open circular pond (3000L) cultivation for A. obliquus. Results showed a 2.08 fold increase in lipid productivity under optimized conditions compared to the control, which emphasizes the scalability of the developed strategy even under uncontrolled conditions. In conclusion, the developed combined metal and EDTA stress strategy not only assisted in alleviating the biomass productivity but also enhanced the lipid accumulation which resulted in overall increased lipid productivity under N and P limited condition. Furthermore, the improved carbohydrate and protein productivities observed with the developed lipid enhancement strategy make it suitable for biorefinery approach with multiple products. An improvement in lipid profile and high biodiesel conversion were also observed with this universally applicable and scalable lipid enhancement strategy confirming their potential applicability during large scale cultivation for biodiesel production.

Mixotrophic Cultivation of Scenedesmus sp. as Biodiesel Feedstock

2013 ◽  
Vol 777 ◽  
pp. 268-273 ◽  
Author(s):  
Jing Han Wang ◽  
Hai Zhen Yang ◽  
Feng Wang
Keyword(s):  
Lipid Content ◽  
Synergetic Effect ◽  
Biomass Productivity ◽  
Lipid Productivity ◽  
Biodiesel Production ◽  
Mixotrophic Cultivation ◽  
Heterotrophic Culture ◽  
Glucose Addition ◽  
Biodiesel Feedstock ◽  
Microalgal Biodiesel

Microalgae are a promising feedstock for biodiesel production. Microalgal biodiesel can be obtained under three major cultivation modes, namely, photoautotrophic, heterotrophic, and mixotrophic cultivation. Reported studies of microalgal biodiesel production are mainly based on photoautotrophic cultivation, mixotrophic cultivation has rarely been researched. This paper compared the biomass productivity, lipid content, and lipid productivity of Scenedesmus sp. under photoautotrophic, heterotrophic, and mixotrophic cultivation. Glucose was added as organic carbon source at five concentrations (0.1, 0.5, 1.0, 2.0, 5.0% glucose w/v). Results displayed that microalgal growth was significantly improved in glucose supplied cultures. Synergetic effect of photoautotrophy and heterotrophy existed in all mixotrophic cultures. Highest biomass productivity of 1.307 g·L-1·d-1 and highest lipid productivity of 316 mg·L-1·d-1 was respectively observed under mixotrophic cultivation with 5.0% and 1.0% (w/v) glucose addition. Lipid content of Scenedesmus sp. under mixotrophic cultivation was mostly higher in stationary phase than in exponential phase. Highest lipid content of 27.73% was observed in 1.0% mixotrophic culture, followed by 24.66% in 1.0% heterotrophic culture.

Potential of Mixotrophic Cultivation of Chlorella sorokiniana for Biodiesel Production

2013 ◽  
Vol 779-780 ◽  
pp. 1509-1513
Author(s):  
Jing Han Wang ◽  
Hai Zhen Yang ◽  
Feng Wang
Keyword(s):  
Lipid Content ◽  
Synergetic Effect ◽  
Biomass Productivity ◽  
Chlorella Sorokiniana ◽  
Lipid Productivity ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Mixotrophic Cultivation ◽  
Promising Alternative ◽  
Microalgal Biodiesel

Biodiesel from microalgae provides a promising alternative for biofuel production. Microalgal biodiesel can be produced under three major cultivation modes, namely, photoautotrophic, heterotrophic, and mixotrophic cultivation. Studies of biodiesel production from microalgae have been reported mostly focusing on photoautotrophic cultivation, mixotrophic cultivation has rarely been researched. This paper compared the biomass productivity, lipid content, and lipid productivity ofChlorella sorokinianaunder photoautotrophic, heterotrophic, and mixotrophic cultivation. Glucose was adopted as organic carbon source at five concentrations (0.1, 0.5, 1.0, 2.0, 5.0% glucose w/v). Results displayed that microalgal growth was significantly improved in glucose supplied cultures. Synergetic effect of photoautotrophy and heterotrophy existed in mixotrophic cultivation except for 5.0% culture. Highest biomass productivity of 1.178 g·L-1·d-1and highest lipid productivity of 582 mg·L-1·d-1was observed under mixotrophic cultivation with 2.0% (w/v) glucose addition. Lipid content ofC. sorokinianawas mostly higher in stationary phase than in exponential phase. Highest lipid content of 49.37% was observed in 2.0% mixotrophic culture, followed by 47.09% in 2.0% heterotrophic culture.

scholarly journals Metabolic response of Botryococcus braunii to high bicarbonate dosages and other conditions: analysis of photosynthetic performance, productivity, and lipidomic profile

2021 ◽  
Author(s):  
Néstor David Giraldo ◽  
Sandra Marcela Correa ◽  
Andrés Arbeláez ◽  
Felix L. Figueroa ◽  
Rigoberto Ríos-Estepa ◽  
...  
Keyword(s):  
Nutrient Limitation ◽  
Metabolic Response ◽  
Neutral Lipids ◽  
Biomass Productivity ◽  
Botryococcus Braunii ◽  
Photosynthetic Performance ◽  
Lipid Productivity ◽  
Cellular Growth ◽  
Adaptive Responses ◽  
Nitrogen And Phosphorus

AbstractIn this study the metabolic responses of Botryococcus braunii were analyzed upon different inorganic carbon dosages and nutrient limitation conditions in terms of lipid and biomass productivity, as well as photosynthetic performance. The nutritional schemes evaluated included different levels of sodium bicarbonate and nitrogen and phosphorus starvation, which were contrasted against standard cultures fed with CO2. Bicarbonate was found to be an advantageous carbon source since high dosages caused a significant increase in biomass and lipid productivity, in addition to an enhanced photosynthetic quantum yield and neutral lipids abundance. This contrasts to the commonly used approach of microalgae nutrient limitation, which leads to high lipid accumulation at the expense of impaired cellular growth, causing a decline in overall lipid productivity. The lipidome analysis served to hypothesize about the influence of the nutritional context on B. braunii structural and storage lipid metabolism, besides the adaptive responses exhibited by cells that underwent nutrient stress.

scholarly journals Coupling of Nutrient Removal and Biodiesel Production By Asterarcys quadricellulare Microalga Grown in Municipal Wastewater

2021 ◽  
Author(s):  
Hanaa Morsi ◽  
Hamed Eladel ◽  
Ayah Maher
Keyword(s):  
Municipal Wastewater ◽  
Basal Medium ◽  
Biomass Productivity ◽  
International Standards ◽  
Lipid Productivity ◽  
Biodiesel Production ◽  
Fatty Acids Profile ◽  
High Lipid ◽  
Biodiesel Feedstock ◽  
Profile Estimation

Abstract The present study focused on the feasibility of using municipal wastewater (WW) as culture medium for cultivation of microalgae. The study aimed to assess the efficiency of microalgae in nutrients removing capacity from wastewater and its biomass and lipid productivity for using as biodiesel feedstock. Based on that, the green microalga Asterarcys quadricellulare was isolated and grown for 24 days in Bold’s Basal Medium as a control and at different concentration of secondary treated municipal wastewater (WW) diluted with distilled water (25%, 50%, 75% and 100%WW). Results of 75%WW treatment recorded 96.6%, 98.4%, and 89.9% removal efficiency for, nitrate, ammonia and total phosphorus, respectively. Also, it revealed high biomass productivity and biomass content, where it recorded 69.0 mgL-1 day-1, and 1.44 g/L, respectively. Likewise, high lipid productivity 17.2 mg L−1 day−1 and 360.6 mg/L lipid content. Consequently, Asterarcys quadricellulare fatty acids profile estimation revealed an increase in Oleic, Palmitic and Linoleic acids levels. Most properties of biodiesel derived from the studied microalga meet with values established by the ASTM D6751 and EN 14214 biodiesel standards. According to this analysis, A. quadricellulare microalga could be used for wastewater bioremediation and biomass production with a suitable content of lipids proper as biodiesel feedstock. The predictive biodiesel properties pointed that it has a good quality compared with international standards.

scholarly journals Operation Regimes: A Comparison Based on Nannochloropsis oceanica Biomass and Lipid Productivity

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1542
Author(s):  
Inês Guerra ◽  
Hugo Pereira ◽  
Margarida Costa ◽  
Joana T. Silva ◽  
Tamára Santos ◽  
...  
Keyword(s):  
Large Scale ◽  
Continuous Cultivation ◽  
Fold Increase ◽  
Continuous Operation ◽  
Lipid Productivity ◽  
Biodiesel Production ◽  
Nannochloropsis Oceanica ◽  
Operation Regime ◽  
Significant Research ◽  
Tubular Photobioreactors

Microalgae are currently considered to be a promising feedstock for biodiesel production. However, significant research efforts are crucial to improve the current biomass and lipid productivities under real outdoor production conditions. In this context, batch, continuous and semi-continuous operation regimes were compared during the Spring/Summer seasons in 2.6 m3 tubular photobioreactors to select the most suitable one for the production of the oleaginous microalga Nannochloropsis oceanica. Results obtained revealed that N. oceanica grown using the semi-continuous and continuous operation regimes enabled a 1.5-fold increase in biomass volumetric productivity compared to that cultivated in batch. The lipid productivity was 1.7-fold higher under semi-continuous cultivation than that under a batch operation regime. On the other hand, the semi-continuous and continuous operation regimes spent nearly the double amount of water compared to that of the batch regime. Interestingly, the biochemical profile of produced biomass using the different operation regimes was not affected regarding the contents of proteins, lipids and fatty acids. Overall, these results show that the semi-continuous operation regime is more suitable for the outdoor production of N. oceanica, significantly improving the biomass and lipid productivities at large-scale, which is a crucial factor for biodiesel production.

scholarly journals Optimization cultivation of Chlamydomonas reinhardtii in a tubular photobioreactor (2000 Liter) for biomass and green bioenergy (biodiesel) production

2020 ◽  
Vol 48 (3) ◽  
pp. 1439-1457
Author(s):  
Hanaa H. ABD EL BAKY ◽  
Gamal S. EL BAROTY
Keyword(s):  
Fatty Acids ◽  
Chlamydomonas Reinhardtii ◽  
Lipid Content ◽  
Large Scale ◽  
Saturated Fatty Acids ◽  
Economic Feasibility ◽  
Lipid Productivity ◽  
Biodiesel Production ◽  
Tubular Photobioreactor ◽  
High Lipid

The biodiesel can be produced from diverse microalgae lipids as alternative and renewable fuel. Thus, the aim of this study was to optimize the Chlamydomonas reinhardtii promising species as biodiesel feedstock for large-scale cultivation in Egypt. To understand some of the triggers required for the metabolic pathway switch to lipid accumulation, the effect of carbon sources and the three elements availability (N, P, S) in C. reinhardtii growth medium was determined. A local microalgae C. reinhardtii was cultured in modified Sueoka medium containing various concentrations of CO2 and bicarbonate (NaHCO3) (in 2-liter flasks) as a carbon source. The optimal source in term biomass, high lipid productivity (10.3 mgL-1d-1) and a higher lipid content (22.76%) were obtained in 6% CO2 culture. Then, the availability of N, P, S (various concentrations of N, P and S) nutrients elements was added to 6% CO2 culture, for produce a highest lipid content and lipid productivity. As expected, under low availability N-1.78 mM; P-0.14mM and S-0.10 mM mediums, C. reinhardtii showed a high accumulation lipid content. Therefore, to improve the economic feasibility of microalgae biofuels production, its concentrations were selected to combine (N+P+S) in order to cultivation of C. reinhardtii in a multi-tubular photobioreactor (400 liter) to produce high lipid contents. Under limited condition, the biomass dry weight, biomass productivity, lipid content and lipid productivity were found to be 3.11 (gL-1), 0.15±0.012 (g-1L-1d-1), 22.76% (w/w %) and 1.9± 0.35 (mg-1L-1d-1), respectively. The extracted lipid was found to have physical and chemical properties similar that plant oils using for biodiesel production. The FAME profiling of prepared biodiesel shows the presence of considerable amount of 36.97% saturated fatty acids (palmitic acid and stearic acid, together) with 27.33% unsaturated (oleic acid and linoleic acid) fatty acids. The FAME had a low iodine value and high CN, which meet with the appropriate of biodiesel standards (EN 14214 and ASTM D6751). Thus, C. reinhardtii appears to be more feasible for high quality biodiesel production.

scholarly journals Formulation of a minimal nutritional medium for enhanced lipid productivity in Chlorella sp. and Botryococcus sp. using response surface methodology

2018 ◽  
Vol 77 (6) ◽  
pp. 1660-1672 ◽  
Author(s):  
Rashi Vishwakarma ◽  
Dolly Wattal Dhar ◽  
Sunil Pabbi
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Large Scale ◽  
Biomass Productivity ◽  
Biodiesel Production ◽  
Lipid Yield ◽  
Chlorella Sp ◽  
Nutritional Medium ◽  
Single Super Phosphate ◽  
Muriate Of Potash

Abstract Chlorella sp. MCC 7 and Botryococcus sp. MCC 31 were investigated to enable large-scale biodiesel production from minimal constituents in the growth medium. Response surface methodology (RSM) was used to maximise the biomass productivity and lipid yield using only nitrogen (N), phosphorus (P) and potassium (K) as urea, single super phosphate and muriate of potash. The optimum values were 0.42 g/L nitrogen; 0.14 g/L phosphorus and 0.22 g/L potassium for Chlorella sp.; and 0.46 g/L; 0.14 g/L and 0.25 g/L for Botryococcus sp. Lipid yield of 42% for Chlorella sp. and 52% in Botryococcus sp. was observed. An enhancement in lipid yield by approximately 55% for Chlorella sp. and 73% for Botryococcus sp. was registered as compared to original nutrient medium. Fourier transform infrared (FTIR) analysis of extracted lipids revealed characteristic bands for triglycerides. This study provided utilisation of a practicable nutrient recipe in the form of N, P, K input for enhanced lipid yield from the selected microalgal strains.

scholarly journals Nutrients formulation to maximize Ankistrodesmus sp. microalgal cell biomass and lipid productivities

2019 ◽  
Vol 92 (2) ◽  
Author(s):  
Wanida Pan-utai ◽  
Penjit Srinophakun ◽  
Wilasinee Inrung
Keyword(s):  
Culture Media ◽  
Lipid Production ◽  
Scale Up ◽  
Biomass Productivity ◽  
Lipid Productivity ◽  
Nutrient Contents ◽  
Media Formulation ◽  
Cell Biomass ◽  
Burman Design ◽  
Plackett Burman Design

Ankistrodesmus sp. belongs to a group of microalgae which plays a significant role in various applications. Availability of nutrients is one of the primary factors regulating the growth and development of microalgae. Twelve experiments were run to determine the optimum media formulation of significant nutrient components for maximum biomass and lipid productivities of Ankistrodesmus sp. IFRPD 1061 cultivation using Plackett- Burman design. All nutrients significantly affected biomass productivity. Highest lipid productivity may not only necessarily originate from biomass cells with highest lipid content but also depend on nutrient formulation of culture media. Microalgal cell growth rate plays a major role in biomass and lipid production. Some nutrients including phosphorus and sodium did not significantly affect lipid productivity, therefore, optimizing nutrient contents could be applied to further scale-up microalgal production.

Solid Lipid Nanoparticles: A Promising Drug Delivery Technology

2009 ◽  
Vol 2 (2) ◽  
pp. 509-516
Author(s):  
S. Pragati ◽  
S. Kuldeep ◽  
S. Ashok ◽  
M. Satheesh
Keyword(s):  
Drug Delivery ◽  
Solid Lipid Nanoparticles ◽  
Large Scale ◽  
Colloidal Particles ◽  
Scale Up ◽  
Lipid Nanoparticles ◽  
Scale Production ◽  
Research Activity ◽  
New Approach ◽  
Solid Lipid

One of the situations in the treatment of disease is the delivery of efficacious medication of appropriate concentration to the site of action in a controlled and continual manner. Nanoparticle represents an important particulate carrier system, developed accordingly. Nanoparticles are solid colloidal particles ranging in size from 1 to 1000 nm and composed of macromolecular material. Nanoparticles could be polymeric or lipidic (SLNs). Industry estimates suggest that approximately 40% of lipophilic drug candidates fail due to solubility and formulation stability issues, prompting significant research activity in advanced lipophile delivery technologies. Solid lipid nanoparticle technology represents a promising new approach to lipophile drug delivery. Solid lipid nanoparticles (SLNs) are important advancement in this area. The bioacceptable and biodegradable nature of SLNs makes them less toxic as compared to polymeric nanoparticles. Supplemented with small size which prolongs the circulation time in blood, feasible scale up for large scale production and absence of burst effect makes them interesting candidates for study. In this present review this new approach is discussed in terms of their preparation, advantages, characterization and special features.

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