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1.
J Environ Manage ; 356: 120631, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38522275

RESUMEN

In this work the effects of nutrient availability and light conditions on CO2 utilization and lipid production in Micractinium pusillum KMC8 is reported. The study investigated the ideal nitrogen concentrations for growth and nitrogen utilization in a 15% CO2 environment. Logistic and Gompertz models were employed to analyze the kinetics of KMC8 cell growth. Compared to 17.6 mmol L-1 control nitrogen, which generated 1.6 g L-1 growth, doubling and quadrupling nitrogen concentrations boosted biomass growth by 12.5% and 28.78%. At 8.6 mmol L-1 nitrogen, the growth decreased but lipid productivity increased to 18.62 mg L-1 day-1. At 70.6 mmol L-1 nitrogen, elevated nitrogen levels maintained an alkaline pH above 7 and enhanced CO2 mitigation, achieving 2.27% CO2 utilization efficiency. Nitrogen shows a positive correlation with higher rates of carbon and nitrogen fixation. The investigation extends to find out the influence of phosphorus and light conditions on microalgae. Increasing light intensity incrementally from 150 to 1200 µmol m-2 s-1 with more phosphorus increased biomass productivity by 85% (255 mg L-1 day-1) and lipid productivity by 2.5-fold (84.76 mg L-1 day-1), with 3.3% CO2 utilization efficiency compared to directly using 1200 µmol m-2 s-1. This study suggests a water recycling-fed batch cycle with gradual light feeding, which results in high CO2 fixation (1.1 g L-1 day-1), 7% CO2 utilization, and significant biomass and lipid productivity (577.23 and 150 mg L-1 day-1). This approach promotes lipid synthesis, maintains carbon fixation, and minimizes biomass loss, thus supporting sustainable bioenergy development in a circular bio-economy framework.


Asunto(s)
Microalgas , Microalgas/metabolismo , Dióxido de Carbono/metabolismo , Biomasa , Nitrógeno/metabolismo , Fósforo/metabolismo , Nutrientes , Lípidos
2.
Bioresour Technol ; 395: 130409, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38295959

RESUMEN

Traditionally, the time of maximum biomass concentration in stage I is the widely adopted stage conversion time in two-stage microalgae culture. This study challenges this conventional approach, demonstrating that the optimal stage conversion time in stage I is 72 h rather than 120 h for achieving maximum biomass concentration. A comparison of cell characteristics revealed that algal cells at 72 h exhibited better growth potential, leading to a higher biomass concentration after transfer to stage II and, consequently, increased lipid productivity. Moreover, the use of phosphorus repletion (5-fold) in stage II directed carbon flux toward biomass growth and lipid accumulation, thereby enhancing lipid productivity. By optimizing the stage conversion time and implementing phosphorus repletion, the mean lipid productivity of Auxenochlorella pyrenoidosa cultured under autotrophy-nitrogen starvation and autotrophy-high light conditions increased by 31 % and 60 %, respectively. This study underscores the importance of reevaluating the currently widely used stage conversion time.


Asunto(s)
Chlorophyta , Microalgas , Chlorophyta/metabolismo , Biomasa , Nitrógeno/metabolismo , Microalgas/metabolismo , Fósforo/metabolismo , Lípidos , Metabolismo de los Lípidos
3.
Chemosphere ; 285: 131475, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34273702

RESUMEN

This study was aimed to assess the growth and lipid productivity improvement of a green microalga Scenedesmus obliquus by mixotrophic cultivation, via addition of sodium acetate (NaAc) into actual municipal wastewater (AMW). Moreover, the nutrient removal efficiency of the culture media in terms of carbon, nitrogen, and phosphorus was investigated. The results showed that the S. obliquus grew better in the AMW than in the BG11 medium (0.20 g L-1 vs 0.16 g L-1 in dry cell weight), and the final algal lipid productivity was higher (9.02 mg L-1 d-1 vs 7.75 mg L-1 d-1, P < 0.05). Further, the addition of NaAc significantly stimulated the algal growth and lipid productivity. Specifically, the highest improvement was obtained by the NaAc-addition of 1 g L-1, where the algal dry cell weight increased 2.40 times than that in the AMW with little organic carbon (0.48 mg L-1 vs 0.20 mg L-1, P < 0.01), and the corresponding algal lipid productivity increased 2.44 time (22.08 mg L-1 d-1 vs 9.02 mg L-1 d-1, P < 0.01). Meanwhile, the addition of 1 g L-1 of NaAc significantly increased the microalga-driven nitrogen and phosphorus removal efficiency, respectively by 1.75 and 2.23 times (82.20% vs 46.85% for total nitrogen, and 76.35% vs 34.18% for total phosphorus). In summary, this study confirmed the feasibility of using organic carbon-supplemented AMW to replace the artificial media for microalgae-based lipid production and nutrient recycling.


Asunto(s)
Microalgas , Scenedesmus , Biocombustibles , Biomasa , Lípidos , Nitrógeno , Nutrientes , Fósforo , Aguas Residuales
4.
J Environ Manage ; 271: 111041, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32778320

RESUMEN

Lipid production in microalgae under nitrogen (N) starved condition can be enhanced by excess phosphorus (P) supply in the second stage of two-stage cultivation strategy. However, implementing two-stage cultivation is difficult in large-scale cultivation system as it requires high energy of transferring large algal biomass from first stage to second stage. To address this problem, we have optimized a continuous two-stage (CTS) cultivation strategy using Chlorella sp. HS2, where nitrogen in the growth environment is depleted naturally via consumption. To enhance both biomass and lipid productivity this strategy explored supplementation of additional P from 50% to 2500% of the initial concentration at the start of N-limited second stage of growth. The results of the optimization study in photobioreactor (PBR) showed that supplementing 500% of initial P and 100% of initial other nutrients (O) (N0-P500-O100) on 5th day showed the maximum biomass productivity of 774.4 mg L-1 d-1. It was observed that Chlorella sp. HS2 grown in PBR yielded higher biomass (3.8 times), lipid (6.1 times) and carbohydrate (5.5 times) productivity in comparison to the open raceway ponds (ORP) study, under optimum nutrient and carbon supply condition. The maximum lipid (289.6 mg L-1 d-1) and carbohydrate (219.2 mg L-1 d-1) productivities were obtained in TPBR-3, which were 1.9 and 1.3 times higher than that of TPBR-2 (+ve control) and 9.6 and 3.7 times higher than that of TPBR-1 (-ve control), respectively. Fatty acid mainly composed of C16/C18 (84.5%-85.7%), which makes the microalgal oil suitable for biofuel production. This study concluded that feeding excess amount of P is an effective and scalable strategy to improve the biomass and lipid productivity of CTS cultivation.


Asunto(s)
Chlorella , Microalgas , Biocombustibles , Biomasa , Fósforo , Fotobiorreactores
5.
J Environ Manage ; 250: 109529, 2019 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-31518792

RESUMEN

Generation of biodiesel from microalgae grown in wastewater can offer a cost-effective approach, whilst wastewaters usually do not contain the optimum concentrations of the essential nutrients and carbon sources that result in lowering the productivities of biomass and lipid. This study aimed to overcome this limitation by manipulating wastewater with various concentrations of nutrients (NO3-, PO43-, Cl- and SO42-) and three carbon sources either individually or in combination to cultivate Micractinium reisseri for biodiesel production. Initially, various dilutions of wastewater were tested and a concentration up to 75% of wastewater showed the highest biomass productivity (0.076 g L-1 d-1) and lipid productivity (0.014 g L-1 d-1). The optimum manipulating conditions for maximum lipid production and the highest productivity required 50% decrease in phosphorous from the concentration of the control medium and supplementation with 1.0 g L-1 of glucose. Under this condition, biomass and lipid productivities increased by 1.7 and 4-folds, respectively, compared to those observed in the control. Furthermore, phosphorous starvation condition in the presence of glucose significantly improved fatty acid profile in the biomass and biodiesel quality related parameters.


Asunto(s)
Biocombustibles , Microalgas , Biomasa , Suplementos Dietéticos , Lípidos , Nutrientes , Aguas Residuales
6.
Sci Total Environ ; 687: 1107-1126, 2019 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-31412448

RESUMEN

Considerable research activities are underway involving microalgae species in order to treat industrial wastewater to address the waste-to-bioenergy economy. Several studies of wastewater treatment using microalgae have been primarily focused on removal of key nutrients such as nitrogen and phosphorus. Although the use of wastewater would provide nutrients and water for microalgae growth, the whole process is even more complex than the conventional microalgae cultivation on freshwater media. The former one adds several gridlocks to the system. These gridlocks are surplus organic and inorganic nutrients concentration, pH of wastewater, wastewater color, total dissolved solids (TDS), microbial contaminants, the scale of photobioreactor, batch versus continuous system, harvesting of microalgae biomass etc. The present review discusses, analyses, and summarizes key aspects involved in the treatment of wastewaters from distillery, food/snacks product processing, and dairy processing industry using microalgae along with sustainable production of its biomass. This review further evaluates the bottlenecks for individual steps involved in the process such as pretreatment of wastewater for contaminants removal, concentration tolerance/dilutions, harvesting of microalgae biomass, and outdoor scale-up. The review also describes various strategies to optimize algal biomass and lipid productivities for various wastewater and photobioreactor type. Moreover, the review emphasizes the potential of co-cultivation of microorganism such as yeast and bacteria along with microalgae in the treatment of industrial wastewater.


Asunto(s)
Microalgas , Eliminación de Residuos Líquidos/métodos , Agricultura , Nitrógeno , Nutrientes , Fósforo , Fotobiorreactores , Aguas Residuales/química
7.
Bioresour Technol ; 273: 297-304, 2019 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30448681

RESUMEN

Approaches to improve wastewater treatment by microalgae have objectives of greater culture control, efficient nutrient removal and increased lipid content. This work designed a bio-photoelectrolysis cell (BPE) system to modulate wastewater treatment by electric current. The electric current had the capacity to enrich entrapped cell weight with a 0.72-fold increase, which resulted in high daily nutrient removal, with 6.78 mg/L/d for nitrogen and 2.14 mg/L/d for phosphorus at 0.6 A/m2. As the nutrient removal was mostly dependent on cell growth, the 1.17-fold increase of lipid productivity was achieved. The harvesting at 6 A/m2 required lower energy input of 1.77 KWh/kg. For the recyclability of treatment, BPE system could continuously treat the fresh wastewater for at least three cycles with biomass and lipid productivities of 68.67 and 22.04 mg/L/d, respectively. The nitrogen removal model of Cst = 45.52-5.52exp(0.45 t) and phosphorus removal model of Cst = 12.54-1.48exp(0.45 t) were established to evaluate the stability of BPE system.


Asunto(s)
Eliminación de Residuos Líquidos/economía , Aguas Residuales/química , Biomasa , Análisis Costo-Beneficio , Electrólisis , Lípidos/biosíntesis , Nitrógeno/metabolismo , Fósforo/metabolismo , Procesos Fotoquímicos , Aguas Residuales/economía
8.
Bioresour Technol ; 268: 286-291, 2018 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-30086455

RESUMEN

This study was conducted to evaluate the efficiency of treatment by C. zofingiensis, C. vulgaris and Scenedesmus sp. in terms of nutrient loading, lipid productivity and the activity of photosystem II. Results from nutrient loading suggested that the nitrogen loading of C. zofingiensis at 0.406 mg/L/h was higher than C. vulgaris and Scenedesmus sp., and the phosphorus loading of C. zofingiensis at 0.075 mg/L/h was higher than C. vulgaris. During the treating process, C. zofingiensis accumulated lipid with higher productivity of 26.57 mg/L/d than C. vulgaris and Scenedesmus sp. In combination with photosynthetic efficiency, C. zofingiensis possessed superior trophic transfer efficiency and absorption capability, even in worse environmental conditions. C. zofingiensis, therefore, exhibited the promising application prospect in wastewater treatment.


Asunto(s)
Chlorella , Purificación del Agua , Biomasa , Chlorella vulgaris , Microalgas , Nitrógeno , Fósforo , Aguas Residuales
9.
Bioresour Technol ; 262: 1-8, 2018 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-29684784

RESUMEN

This work investigated the production of Scenedesmus sp. in semi-continuous mode in three pilot-scale outdoor raceways (7.2 m2) using flue gas for CO2 supply and centrate from the anaerobic digestion of urban wastewater as the sole nutrient source. Experiments were performed at different culture depths, 5, 10 and 15 cm, while evaluating two centrate concentrations (30% and 45%) at dilution rates of 0.2 and 0.3 d-1. Under optimal conditions of 30% centrate, 0.3 d-1 dilution rate and a 15 cm culture depth, a maximum biomass productivity of 22.9 g m-2 d-1 was obtained. The optical properties of the cultures were studied and the results showed a photosynthetic efficiency of up to 2.0% and a quantum yield of 0.3 g biomass E-1. Nitrogen and phosphorus removal rates of 3 g N m-2 d-1 and 0.6 g P m-2 d-1 were recorded, respectively. Lipid productivity of 2.3 g m-2 d-1 was determined possessing a suitable fatty acids profile for biofuel production.


Asunto(s)
Scenedesmus , Aguas Residuales , Biomasa , Gases , Microalgas , Nitrógeno/aislamiento & purificación , Fósforo/aislamiento & purificación
10.
World J Microbiol Biotechnol ; 34(2): 25, 2018 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-29330693

RESUMEN

Brewery effluent (BE) as an appreciable and sustainable resource presented new possibilities in low-cost algal biomass production, whereas the relatively low essential macronutrients hindered extensive applications as growth medium for microalgae cultivation. The objective of this study was to investigate the feasibility of an integrated treatment strategy initiated by BE coupling phytohormones in augmenting biomass and lipid accumulation in Coccomyxa subellipsoidea. Results revealed that BE coupling synthetic 1-naphthaleneacetic acid (NAA) accomplished the favorable lipid productivity of 481.76 mg/L/days, representing 6.80- to 9.71-fold more than that of single BE as well as standard Basal media. BE coupling NAA feeding also heightened the proportions of C16-C18 fatty acids (over 96%) and mono-unsaturated C18:1 (approximate 45%) which were prone to high-quality biofuels-making. Such profound lipids accumulation might be attributable to that BE coupling NAA treatment drove most of metabolic flux (i.e. acetyl-CoA) derived from TCA cycle and glycolysis flowing into lipid accumulation pathway. Concurrently, the complete removal of total nitrogen and total phosphorus by C. subellipsoidea with assistance of NAA were easily complied with the permissible dischargeable limits for BE. These present results strongly demonstrated that BE coupling NAA was a potential feeding strategy in boosting algal lipid productivity and further provided great possibilities in linking affordable algal biomass production with high-efficient biological contaminants removal.


Asunto(s)
Biomasa , Chlorophyta/crecimiento & desarrollo , Chlorophyta/metabolismo , Lípidos/biosíntesis , Reguladores del Crecimiento de las Plantas/farmacología , Biocombustibles , Vías Biosintéticas/efectos de los fármacos , Fenómenos Químicos/efectos de los fármacos , Medios de Cultivo/metabolismo , Ácidos Grasos/biosíntesis , Metabolismo de los Lípidos/efectos de los fármacos , Microalgas/crecimiento & desarrollo , Microalgas/metabolismo , Ácidos Naftalenoacéticos/metabolismo , Nitrógeno/metabolismo , Fósforo/metabolismo
11.
Environ Sci Pollut Res Int ; 25(1): 353-362, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-29039037

RESUMEN

The potential of lipid accumulation by oleaginous yeast Cryptococcus vishniaccii grown on amaranth seed aqueous extract (AAE) media was assessed. Maximum cell biomass productivity of 104 mg/L/h, lipid productivity of 54 mg/L/h, and lipid content of 52.31% were recorded on AAE when carbon to nitrogen (C:N) ratio increased from 134 to 147 after removal of ammonia nitrogen. The lipid droplet (LD) size (2.32 ± 0.38 µm) was visualized by fluorescence microscopy using Nile red stain indicating maximum accumulated triacylglycerol (TAG) at C:N 147. Fatty acid methyl ester (FAME) profile obtained after transesterification of extracted lipid revealed the presence of palmitic acid (16:0), palmitoleic acid (16:1), stearic acid (18:0), oleic acid (18:1), and linoleic acid (18:2). Data showed the presence of high monounsaturated fatty acid (MUFA) content (68.17%) depicting improved winter operating conditions of biodiesel. Various quality parameters of biodiesel were evaluated and compared to the American and European biodiesel standards specifications. Based on the lipid productivity, distribution of fatty acids, and evaluated properties obtained; the lipid accumulation by C. vishniaccii utilizing amaranth seeds as substrate could serve as a feasible feedstock for biodiesel production.


Asunto(s)
Amaranthus/microbiología , Biocombustibles/análisis , Biotecnología/métodos , Cryptococcus/metabolismo , Semillas/microbiología , Amaranthus/química , Biomasa , Cryptococcus/crecimiento & desarrollo , Ácidos Grasos/análisis , Gotas Lipídicas/metabolismo , Extractos Vegetales/química , Semillas/química
12.
Mar Biotechnol (NY) ; 19(3): 219-231, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28456869

RESUMEN

Lipid production is an important indicator for evaluating microalgal species for biodiesel production. In this study, a new green microalga was isolated from a salt lake in Egypt and identified as Asteromonas gracilis. The main parameters such as biomass productivity, lipid content, and lipid productivity were evaluated in A. gracilis, cultivated in nutrient-starved (nitrogen, phosphorous), and salinity stress as a one-factor-at-a-time method. These parameters in general did not vary significantly from the standard nutrient growth media when these factors were utilized separately. Hence, response surface methodology (RSM) was assessed to study the combinatorial effect of different concentrations of the abovementioned factor conditions and to maximize the biomass productivity, lipid content, and lipid productivity of A. gracilis by determining optimal concentrations. RSM optimized media, including 1.36 M NaCl, 1 g/L nitrogen, and 0.0 g/L phosphorus recorded maximum biomass productivity, lipid content, and lipid productivity (40.6 mg/L/day, 39.3%, and 15.9 mg/L/day, respectively) which agreed well with the predicted values (40.1 mg/L/day, 43.6%, and 14.6 mg/L/day, respectively). Fatty acid profile of A. gracilis was composed of C16:0, C16:1, C18:0, C18:3, C18:2, C18:1, and C20:5, and the properties of fuel were also in agreement with international standards. These results suggest that A. gracilis is a promising feedstock for biodiesel production.


Asunto(s)
Biocombustibles , Chlorophyta/química , Ácidos Grasos/química , Biomasa , Medios de Cultivo/química , Lípidos/análisis , Nitrógeno/química , Fósforo/química , Salinidad
13.
Environ Sci Pollut Res Int ; 23(20): 20997-21007, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27488714

RESUMEN

The study illustrates the synergistic potential of novel microalgal, Chlamydomonas debaryana IITRIND3, for phycoremediation of domestic, sewage, paper mill and dairy wastewaters and then subsequent utilisation of its biomass for biodiesel production. Among these wastewaters, maximum lipid productivity (87.5 ± 2.3 mg L-1 day-1) was obtained in dairy wastewater with removal efficiency of total nitrogen, total phosphorous, chemical oxygen demand and total organic carbon to be 87.56, 82.17, 78.57 and 85.97 %, respectively. Metal ions such as sodium, calcium, potassium and magnesium were also removed efficiently from the wastewaters tested. Pigment analysis revealed loss of chlorophyll a while increase in carotenoid content in algal cells cultivated in different wastewaters. Biochemical data of microalgae grown in different wastewaters showed reduction in protein content with an increase in carbohydrate and lipid contents. The major fatty acids in algal cells grown in dairy wastewater were C14:0, C16:0, C16:1, C18:0, C18:2 and C18:3. The physical properties of biodiesel derived from microalgae grown in dairy wastewater were in compliance with the ASTM D6751 and EN 14214 fuel standards and were comparable to plant oil methyl esters.


Asunto(s)
Biocombustibles , Chlamydomonas/metabolismo , Microalgas/metabolismo , Biodegradación Ambiental , Análisis de la Demanda Biológica de Oxígeno , Biomasa , Clorofila/metabolismo , Clorofila A , Industria Lechera , Residuos Industriales , Metabolismo de los Lípidos , Metales/metabolismo , Nitrógeno/metabolismo , Fósforo/metabolismo , Aguas Residuales , Contaminantes Químicos del Agua/metabolismo
14.
Bioresour Technol ; 218: 161-6, 2016 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-27367812

RESUMEN

Filamentous microalgae Tribonema is promising for biodiesel production in terms of high lipid content, easy harvesting and good contamination tolerance. As high lipid productivity is a key basis, several methods including different culture medium, phosphorus, iron and CO2 inductions were tested to enhance lipid productivity in Tribonema minus. T. minus subjected to BG11-freshwater medium achieved a favorable lipid productivity of 216.18mgL(-1)d(-1), much higher than those in other culture medium (BG11-S, Kuhl, f/2, f, 2f, BBM, ASW and ES). Secondly, the optimal phosphorus, iron and CO2 concentrations for high lipid productivity of T. minus were obtained, respectively. Finally, the cells of T. minus grown in optimized BG11 medium containing 80mgL(-1) KH2PO4 and 6mgL(-1) FeC6H5O7·NH4OH with 2% CO2 achieved a lipid productivity of 384.67mgL(-1)d(-1), representing a 1.56-fold increase from the control. Therefore, the strategy to enhance lipid productivity of T. minus was successfully proposed.


Asunto(s)
Biocombustibles , Biomasa , Lípidos/biosíntesis , Microalgas/metabolismo , Estramenopilos/metabolismo , Reactores Biológicos , Dióxido de Carbono/química , Medios de Cultivo/química , Hierro/química , Lípidos/química , Fósforo/química
15.
Appl Biochem Biotechnol ; 180(1): 109-21, 2016 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-27093970

RESUMEN

This investigation utilized sugarcane bagasse aqueous extract (SBAE), a nontoxic, cost-effective medium to boost triacylglycerol (TAG) accumulation in novel fresh water microalgal isolate Scenedesmus sp. IITRIND2. Maximum lipid productivity of 112 ± 5.2 mg/L/day was recorded in microalgae grown in SBAE compared to modified BBM (26 ± 3 %). Carotenoid to chlorophyll ratio was 12.5 ± 2 % higher than in photoautotrophic control, indicating an increase in photosystem II activity, thereby increasing growth rate. Fatty acid methyl ester (FAME) profile revealed presence of C14:0 (2.29 %), C16:0 (15.99 %), C16:2 (4.05 %), C18:0 (3.41 %), C18:1 (41.55 %), C18:2 (12.41), and C20:0 (1.21 %) as the major fatty acids. Cetane number (64.03), cold filter plugging property (-1.05 °C), and oxidative stability (12.03 h) indicated quality biodiesel abiding by ASTM D6751 and EN 14214 fuel standards. Results consolidate the candidature of novel freshwater microalgal isolate Scenedesmus sp. IITRIND2 cultivated in SBAE, aqueous extract made from copious, agricultural waste sugarcane bagasse to increase the lipid productivity, and could further be utilized for cost-effective biodiesel production.


Asunto(s)
Biocombustibles/microbiología , Biotecnología/métodos , Celulosa/química , Microalgas/metabolismo , Saccharum/química , Scenedesmus/metabolismo , Triglicéridos/metabolismo , Residuos , Procesos Autotróficos/efectos de los fármacos , Biomasa , Carbono/farmacología , Tamaño de la Célula/efectos de los fármacos , Ésteres/metabolismo , Lípidos/biosíntesis , Microalgas/citología , Microalgas/efectos de los fármacos , Microalgas/ultraestructura , Extractos Vegetales/farmacología , Estándares de Referencia , Scenedesmus/citología , Scenedesmus/efectos de los fármacos , Scenedesmus/ultraestructura
16.
Bioresour Technol ; 211: 422-8, 2016 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-27035473

RESUMEN

Despite the vast interest in microalgae as feedstock for biodiesel production, relatively few studies examined their response to diurnal temperature fluctuation. Here, we describe biomass and lipid productivities and fatty acid profiles of thermo-resistant Micractinium sp. and Scenedesmus sp. grown in batch cultures in a laboratory set-up that mimics a typically warm summer day in Central Anatolia with a 16-h light temperature of 30°C and 8-h dark temperature of 16°C (30°C (day)/16°C (night)). Both strains can survive a temperature range of 10-50°C. We found the lipid productivities of Micractinium sp. and Scenedesmus sp. as 30/21mgL(-1)d(-1) and 6/7mgL(-1)d(-1), respectively during the 30°C (day)/16°C (night) cycle. Saturated fatty acid content increased with increasing temperature. Additionally, we cultured Micractinium sp. under Nitrogen (N) and Phosphorus (P) limiting conditions. Highest lipid productivity of 85.4±2mgL(-1)d(-1) was obtained under P-depletion during exponential growth phase. Oleic acid amount also increased eight fold during P-deplete.


Asunto(s)
Biomasa , Lípidos/biosíntesis , Microalgas/crecimiento & desarrollo , Nitrógeno/farmacología , Fósforo/farmacología , Scenedesmus/crecimiento & desarrollo , Temperatura , Biocombustibles/microbiología , Ésteres/metabolismo , Ácidos Grasos/metabolismo , Microalgas/efectos de los fármacos , Microalgas/metabolismo , Scenedesmus/efectos de los fármacos , Scenedesmus/metabolismo
17.
Bioresour Technol ; 213: 79-87, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26970694

RESUMEN

The study synergistically optimized nitrogen and phosphorous concentrations for attainment of maximum lipid productivity in Chlorella minutissima. Nitrogen and phosphorous limited cells (N(L)P(L)) showed maximum lipid productivity (49.1±0.41mg/L/d), 1.47 folds higher than control. Nitrogen depletion resulted in reduced cell size with large sized lipid droplets encompassing most of the intracellular space while discrete lipid bodies were observed under nitrogen sufficiency. Synergistic N/P starvations showed more prominent effect on photosynthetic pigments as to individual deprivations. Phosphorous deficiency along with N starvation exhibited 17.12% decline in carbohydrate while no change in nitrogen sufficient cells were recorded. The optimum N(L)P(L) concentration showed balance between biomass and lipid by maintaining intermediate cell size, pigments, carbohydrate and proteins. FAME profile showed C14-C18 carbon chains in N(L)P(L) cells with biodiesel properties comparable to plant oil methyl esters. Hence, synergistic N/P limitation was effective for enhancing lipid productivity with reduced consumption of nutrients.


Asunto(s)
Biocombustibles , Biotecnología/métodos , Chlorella/metabolismo , Lípidos/biosíntesis , Nitrógeno/farmacología , Fósforo/farmacología , Biomasa , Carbohidratos/análisis , Chlorella/efectos de los fármacos , Chlorella/crecimiento & desarrollo , Ésteres/metabolismo , Pigmentos Biológicos/análisis , Proteínas/análisis
18.
Bioresour Technol ; 194: 117-29, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26188554

RESUMEN

A culture medium based on NPK-10:26:26 fertilizer was formulated for enhanced biomass and lipid production of Dunaliella tertiolecta by selecting appropriate nutrients and environmental parameters. Five-level-five-factor central composite design assisted response surface methodology was adopted for optimal cultivation of D. tertiolecta and results were compared with simple genetic algorithm (GA). Significant improvement in biomass and lipid production was obtained using newly formulated fertilizer medium over f/2 medium. Following optimal parameters [i.e., NaHCO3, (mM), NPK-10:26:26 (g L(-1)), NaCl (M), light intensity (µmol m(-2) s(-1)) and temperature (°C)] were obtained for maximum biomass (1.98 g L(-1)) and lipid production (0.76 g L(-1)): (42.50, 0.33, 1.09, 125, 25.13) and (38.44, 0.40, 1.25, 125, 24.5), respectively using GA. A multi-objective optimization was solved using non-dominated sorting GA to find best operating variables to maximize biomass and lipid production simultaneously. Effects of operating parameters and their interactions on algae and lipid productivity were successfully revealed.


Asunto(s)
Algoritmos , Chlorophyta/crecimiento & desarrollo , Medios de Cultivo , Fertilizantes , Metabolismo de los Lípidos , Análisis de Varianza , Biomasa , Chlorophyta/metabolismo , Medios de Cultivo/química , Luz , Lípidos/biosíntesis , Modelos Teóricos , Nitrógeno/metabolismo , Fósforo/metabolismo , Potasio/metabolismo , Cloruro de Sodio
19.
Ecotoxicol Environ Saf ; 121: 253-7, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25838071

RESUMEN

Lipid from microalgae is one of the putative oil resources to facilitate the biodiesel production during this era of energy dissipation and environmental pollution. In this study, the key parameters such as biomass productivity, lipid productivity and lipid content were evaluated at the early stationary phase of Chlamydomonas reinhardtii, CC1010 cultivated in nutrient starved (nitrogen, phosphorous), glucose (0.05%, 0.1%, 0.15% and 0.2%) and vitamin B12 supplementation (0.001%, 0.002% and 0.003%) in Tris-Acetate-Phosphate (TAP) medium. The lipid content in nitrogen starved media was 61% which is 2.34 folds higher than nutrient sufficient TAP medium. Glucose supplementation has lead to proportional increase in biomass productivity with the increasing concentration of glucose whereas vitamin B12 supplementations had not shown any influence in lipid and biomass production. Further, fatty acid methyl ester (FAME) profiling of C. reinhardtii, CC 1010 has revealed more than 80% of total SFA (saturated fatty acid) and MUFA (mono unsaturated fatty acid) content. Quality checking parameters of biodiesel like cetane number, saponification value, iodine number and degree of unsaturation were analyzed and the biodiesel fuel properties were found to be appropriate as per the international standards, EN 14214 and ASTM D6751. Conclusively, among all the treatments, nitrogen starvation with 0.1% glucose supplementation had yielded high lipid content in C. reinhardtii, CC 1010.


Asunto(s)
Biocombustibles , Biotecnología/métodos , Chlamydomonas reinhardtii/crecimiento & desarrollo , Chlamydomonas reinhardtii/metabolismo , Ácidos Grasos/biosíntesis , Biocombustibles/normas , Biomasa , Ácidos Grasos/análisis , Cromatografía de Gases y Espectrometría de Masas , Glucosa/metabolismo , Lípidos/análisis , Lípidos/biosíntesis , Microalgas/crecimiento & desarrollo , Microalgas/metabolismo , Microscopía Confocal , Nitrógeno/metabolismo , Fósforo/metabolismo
20.
Bioresour Technol ; 157: 84-90, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24534788

RESUMEN

Effect of mine wastewater on the nutrient removal efficiency of a green microalga Micratinium reisseri from concentrated municipal wastewater (CMW) with simultaneous lipid production was investigated. Different dilution ratios (1-10%) of CMW either with mine wastewater (MWF) or mine wastewater without Fe (MWOF) were used. M. reisseri showed the highest growth (0.8gL(-1)) and nutrient uptake (35.9mgTNL(-1) and 5.4mgTPL(-1)) at 3% MWF ([Fe]tot=6.7mgL(-1)), and the highest lipid productivity (10.4mgL(-1)day(-1)) at 5% MWF ([Fe]tot=11.2mgL(-1)) after 15days. CMW supported the algal autoflocculation due to formation of phosphate, calcium and magnesium precipitates at a high suspension pH. Fatty acid methyl ester analysis revealed that the microalgal lipids possessed 79-82% of C16/C18 fatty acids. Application of mine wastewater improved the nutrient removal efficiency, growth and lipid productivity of M. reisseri cultivated in CMW.


Asunto(s)
Chlorophyta/metabolismo , Lípidos/biosíntesis , Microalgas/metabolismo , Minería , Nitrógeno/aislamiento & purificación , Fósforo/aislamiento & purificación , Aguas Residuales/microbiología , Biodegradación Ambiental , Biomasa , Carbono/análisis , Chlorophyta/crecimiento & desarrollo , Ciudades , Ésteres/metabolismo , Ácidos Grasos/metabolismo , Factores de Tiempo , Contaminantes Químicos del Agua/aislamiento & purificación
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