Heterotrophic cultivation of microalgae in photobioreactor using low cost crude glycerol for enhanced biodiesel production (original) (raw)
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Present study used central composite design (CCD) to evaluate algal strains for biodiesel by optimizing their harvesting time and pH. As a preliminary step, green alga Chlorella vulgaris MCRC A0001 and two cyanobacteria Chroococcus turgidus MCRC A0002 and Spirulina platensis MCRC A0005 have been explored for growth in terms of cell number, protein, chlorophyll-a, dry weight and pH from every 5th day till 25th day of growth. Furthermore, no hitherto report on CCD approach to inspect the impact of harvesting period and pH on algal lipid content. As evident from CCD, seemly candidate C. vulgaris MCRC A0001 exhibited high lipid content of 0.22 g dry weight1 on day 20 compared to other strains. Under nitrogen stimulus, C. vulgaris MCRC A0001 grown under 0 g nitrogen/L and 27 C showed 1.39 gL1 biomass which marginally equal to control, and a significant increase in total lipid about 26% which is 4% high over control forum. It is noteworthy that, high biomass coupled with high lipid content was observed in nitrogen deprived and limited cells of C. vulgaris MCRC A0001. Additionally, robust methyl ester yield at 0.69 g g1 was observed in 1:9 ratio of lipid-methanol and 3% NaOH, and ester yield was confirmed by FTIR spectra and gas chromatogram. Besides, gas chromatographic analysis revealed an increase in C16:0 e29.61%, C18:1e25.33%, C18:2e11.3% which are prerequisite for biodiesel production. Further, biodiesel was critically analyzed for Degree of unsaturation (DU-77.32) and Long chain saturation factor (LCSF- 2.96) which accords the European standard.
Evaluation of the Potential of Biodiesel 3G: Heterotrophic Bioreactors
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
Biodiesel derived from microalgae has several benefits over other resources, such as oil productivity. Many microalgae greatly exceeds the best oil producing crops. Nonetheless, in order to make microalgal biodiesel competitive, single-cell oil productivity evaluation is required under different process conditions. This work evaluates the potential of third generation biodiesel (3G) by microalgae Aphanothece microscopica Nägeli cultivate heterotrophically in agro-industrial wastewaters (fish processing, rice parboiling and dairy processing). The results indicate that the single-cell oil productivities reached 0.05, 0.12 and 0.49 g lipid /L.day for cultivations in fish processing, rice parboiling and dairy processing wastewater, respectively. These values are comparable to oil productivities obtained currently with soybean, demonstrating the potential of microalgae as matrix for oil production for biofuels.
The investigation first time reports the efficacy of de-oiled algal biomass extract (DOABE) for mixotrophic cultivation of Chlorella sp. MCC27 to enhance biodiesel production in open tray systems and in BioXpert-V2 software connected photobioreactor (PBR). The cultivation systems with addition of DOABE (PBR systems þ DOABE and open tray system þ DOABE) as media were tested for quality and quantity of biodiesel. The presence of organic carbon and low nitrogen in DOABE caused >2 folds higher biomass productivity and >4 folds enhanced lipid productivity for the cells cultivated in PBR system þ DOABE and open tray system þ DOABE as compared to control (i.e. BBM). Biochemical analysis of cells from both the systems revealed the decrease in total carbohydrates and protein contents. The FAMEs analyses showed vehicular quality biodiesel. PBR system þ DOABE showed edge over open tray system þ DOABE in terms of biomass productivity and lipid content. The physical properties of biodiesel produced from Chlorella sp. MCC27 were more close to the fuel standards (ASTM D6751), when cells were cultivated in open tray system þ DOABE than in PBR system þ DOABE. Collectively, this study highlights the use of DOABE as a low cost feedstock for enhancing vehicular quality biodiesel production from microalgae.
BACKGROUND: The novelty of this work is the estimation of the fuel properties of biodiesel, a comparison study with conventional sources of biodiesel commonly used as feedstock, and an investigation for meeting the requirements of the standard specifications for this fuel produced by six strains of microalgae (three cyanobacteria, two green algae and one diatom), cultivated photosynthetically in a bubble column photobioreactor. Lipid productivity and biofuel quality were the criteria for species selection.
Production and characterization of biodiesel from Chlorococcum sp.: A green microalgae
Environmental Quality Management, 2023
Biodiesel was prepared by extracting oil from Cladophora glomerata green algae followed by transesterification of the oil using NaOH as a catalyst. The algae Oil extraction was carried out using two different techniques (Soxhlet and refluxing) and similar oil yield was obtained (23-24%). The resulting biodiesel showed desirable physical and chemical properties. Specific gravity, acid value, iodine value, ash content and calorific value of the algae biodiesel were within the specification of American Society for Testing and Materials (ASTM) and European Standards (EN). The analysis of fatty acid methyl ester composition revealed, 63, 27 and 10% for 9octadecodenoic, hexadeconic and octadeconoic acid methyl ester, respectively. From the production line, two waste streams (glycerol and residual biomass) were combined to form a glycerine pellet. The measured energy content of the glycerine pellet was found to be comparable with firewood. Therefore, C. glomerata could potentially be utilized for the production of both biodiesel and glycerine pellet with no net waste in the transesterification process.
Microalgae with their higher growth rate and oil volume can be counted on as a new source of producing biodiesel. Chlorella vulgaris microalgae have been used in this study for producing biodiesel. From one germinator device was used as the culture room. The optimum temperature for cultivation was adjusted, 25ºC; pH, 7; Light intensity, 3500 Lux. Due to stiffness of cell envelope of this type of microalgae, the cell envelope was broken using Ultrasonic device in 40°C. The biodiesel produced from transesterification methods was analyzed by gas chromatograph (GC). The biodiesel samples were characterized in accordance with American standard specification for biodiesel (ASTM D6751) and European standard specifications for biodiesel (EN14214) protocols. 18-carbon fatty acids with 51.3% constitute the most fatty acids presence. Olecic acid with 28.10%, Palmitic acid with 24%, Linolelaidic acid with 16.7%, Linolenic acid with 10.6% and Linoleic acid 10% assign the biggest share to themselves respectively. The resultant biodiesel was evaluated for physic-chemical properties namely kinematic viscosity (4.8 mm2/s), density (870 kg/m3), flash point (140 °C), cetane number (60), cloud point (0 °C), pour point (-11 °C), heating value (41MJ/kg). Although the presence of some unsaturated fatty acids increased the pour and cloud point of the biodiesel, the microalgae with its high growth rate however can be considered as a proper source of biodiesel production.