EFFECTS OF SUN AND OVEN DRYING TECHNIQUES ON 1 QUALITY OF OIL PRODUCED FROM CHLORELLA 2 VULGARIS BIOMASS 3 4 5 6 ABSTRACT 7 This study involved the molecular identification of Chlorella vulgaris microalgae obtained 8 from Kaduna State University Fish Pond for biodiesel production potential. The DNA of 9 Chlorella microalgae was extracted and subjected to PCR. The molecular weight of the PCR 10 product obtained was 1.8kb using 18S rDNA primer sets and BLAST analyses revealed 95% 11 identity with Chlorella vulgaris. The Chlorella vulgaris was cultured in open aquaria tanks at 12 the Department of Biological Sciences, Nigerian Defence Academy. The biomass harvested 13 was subjected to varying timings of sun and oven drying techniques (25-35ºC for 72hours 14 and 60ºC for 12hours respectively) before extraction of oil from the biomass using solvent 15 extraction method. The values for the density (0.854 and 0.867cm 3 ), specific gravity (0.875 16 and 0.876), acid value (0.414 and 0.384mgKOH/g), saponification value (173.3 17 and170.1mgKOH/g), kinematic viscosity (5.200 and 3.870mm 2 /g at 40ºC), flash point (114 18 and 115ºC) and cetane number (54.00 and 47.70) for the sun and oven dried biomass oil 19 respectively were found to be in accordance with the ASTM standard values for biodiesel and 20 fossil diesel. GC-MS analyses of the oil extracted using the two drying methods showed that 21 the fatty acid profiling of the oil obtained from sun dried processed biomass had C14:0, 22 C15:0, C16:0, C18:0, C18:1 cis9 and C22:1ω9 while the oven dried biomass oil had C14:0, 23 C16:0, C19:0, C11:1, C18:1 cis9 and C22:1ω9. Drying methods therefore had influenced on 24 the composition of saturated and unsaturated fatty acids. The oven dried biomass oil 25 possesses high monounsaturated fatty acids when compared to sun dried biomass oil though 26 the most important fatty acids (C14:0, C16:0 and C18:1) found in standard biodiesel were 27 present in both. The results suggested that Chlorella vulgaris microalgae can be sustainably 28 harvested for the production of biodiesel. Both drying techniques can be employed for 29 effective extraction. 30 31 Keywords:Micro algae, Chlorella vulgaris, Biodiesel, Biomass 32 33 1. INTRODUCTION 34 1.1 Background of the study 35 Research into the development of sustainable energy resources and the reduction of carbon 36 dioxide emissions is thriving due to soaring oil price and global climate change. Emphasis on 37 the development of renewable, biodegradable, and environmentally friendly industrial fluids, 38 such as diesel and other fuels have raised the need to search for alternative renewable fuels 39 [1]. Among the options for renewable energy, biofuels produced from biomass feedstock are 40 of most interest to the global energy structure [2] [3]. 41
13
Embed
EFFECTS OF SUN AND OVEN DRYING TECHNIQUES ON QUALITY …
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
EFFECTS OF SUN AND OVEN DRYING TECHNIQUES ON 1
QUALITY OF OIL PRODUCED FROM CHLORELLA 2
VULGARIS BIOMASS 3
4
5
6
ABSTRACT 7
This study involved the molecular identification of Chlorella vulgaris microalgae obtained 8
from Kaduna State University Fish Pond for biodiesel production potential. The DNA of 9
Chlorella microalgae was extracted and subjected to PCR. The molecular weight of the PCR 10
product obtained was 1.8kb using 18S rDNA primer sets and BLAST analyses revealed 95% 11
identity with Chlorella vulgaris. The Chlorella vulgaris was cultured in open aquaria tanks at 12
the Department of Biological Sciences, Nigerian Defence Academy. The biomass harvested 13
was subjected to varying timings of sun and oven drying techniques (25-35ºC for 72hours 14
and 60ºC for 12hours respectively) before extraction of oil from the biomass using solvent 15
extraction method. The values for the density (0.854 and 0.867cm
3), specific gravity (0.875 16
and 0.876), acid value (0.414 and 0.384mgKOH/g), saponification value (173.3 17
and170.1mgKOH/g), kinematic viscosity (5.200 and 3.870mm2/g at 40ºC), flash point (114 18
and 115ºC) and cetane number (54.00 and 47.70) for the sun and oven dried biomass oil 19
respectively were found to be in accordance with the ASTM standard values for biodiesel and 20
fossil diesel. GC-MS analyses of the oil extracted using the two drying methods showed that 21
the fatty acid profiling of the oil obtained from sun dried processed biomass had C14:0, 22
C15:0, C16:0, C18:0, C18:1 cis9 and C22:1ω9 while the oven dried biomass oil had C14:0, 23
C16:0, C19:0, C11:1, C18:1 cis9 and C22:1ω9. Drying methods therefore had influenced on 24
the composition of saturated and unsaturated fatty acids. The oven dried biomass oil 25
possesses high monounsaturated fatty acids when compared to sun dried biomass oil though 26
the most important fatty acids (C14:0, C16:0 and C18:1) found in standard biodiesel were 27
present in both. The results suggested that Chlorella vulgaris microalgae can be sustainably 28
harvested for the production of biodiesel. Both drying techniques can be employed for 29
Table 3 present the fatty acids composition of the oven-dried Chlorella vulgaris crude oil. 267
The GC-MS results indicate that the oil has a strike balance of 50% saturated fatty acids 268
(C14H28O2, C16H32O2 and C19H38O2) than 50% unsaturated (C11H20O2, C18H34O2 269
and C22H42O2). 270
271
Table 4. Physico-chemical properties of synthesized Chlorella vulgaris biodiesel in 272
comparison with ASTM standard 273
Property Kinematic Viscosity
mm2/g at 40ºC
Flash Point °C Cetane Number
Sun dried Biomass
Biodiesel
5.200a 114.0 a 54.00 a
Oven dried
Biomass Biodiesel
3.870b 115.0 a 49.70 b
Biodiesel ASTM
Standard
2.800-5.700 96.00-190.0 45.00-70.00
Fossil Diesel ASTM
Standard
1.900-3.800 60.00-80.00 40.00-55.00
Data are represented as mean of triplicate values at P=0.05 274
Table 4 shows the results of the Physico-chemical properties for both sun-dried and oven 275
dried prepared biomass biodiesel in comparison with ASTM standards. A high kinematic 276
viscosity (52.00) and cetane number (54.00) were observed in sun-dried biomass prepared 277
biodiesel in comparison with the kinematic viscosity (3.870) and cetane number (49.70) of 278
oven-dried biomass prepared biodiesel, though both values were within the ASTM standard 279
values for biodiesel and fossil diesel. 280
281
4. DISCUSSION 282
One of our goals was to achieve positive DNA extraction, amplification and sequencing of 283
Chlorophyceae (Chlorella sp) microalgae as a feedstock for biodiesel potential. The result of 284
DNA extraction showed that DNA concentration ranges from 1-10µg. The molecular weight 285
of the PCR product was 1.8kb using a set of 18S rDNA primer sets. This is in consistency 286
with result of [25]. Sequencing and BLAST revealed 95% identity with Chlorella vulgaris 287
strain CCAP 211/11F 18S ribosomal RNA gene. 288
Water has to be removed from Chlorella vulgaris biomass slurry to increase its viability for 289
effective lipid extraction. The time taken for removal of water using the two techniques 290
varied. Sun drying took substantially longer to remove water from the Chlorella vulgaris 291
biomass when compared to oven drying. The short term for the oven drying could be the 292
presence of an air circulating fan in the oven that assisted in uniform distribution of heat and 293
air. Among the two techniques, oven drying have an easy mode of operation but required 294
instrumentation. Sun drying technique required a large drying surface, takes longer drying 295
time, and risk the loss of bioreactive products but it is cheap [13]. 296
Oil yields from Chlorella vulgaris biomass prepared by the two techniques showed no 297
significant difference (P>0.05) in the lipid yield although sundried biomass oil volume was 298
slightly higher than oven drying biomass oil. The insignificant differences could be because 299
the species are the same and longer drying time does not affect the total % of oil yield. 300
Similar findings were reported by Balasubramanian et al. [26] where biomass of 301
Nannochloropsis sp. was dried using sun drying technique. 302
Oil characteristics such as density and specific gravity were studied. The variations in both 303
the densities and specific gravities values are insignificant. This is in agreement with the 304
previous study by Kelaiya et al. [27]. These properties compared favourably with the 305
acceptable biodiesel and diesel standards. 306
A high acid value was observed in sun dried biomass oil compared to oven dried biomass oil. 307
This indicates the presence of high amount of free fatty acids in the sundried biomass oil. 308
This demonstrates that drying methods has influence on the level of free fatty acids. The high 309
level of acid value in sundried biomass oil extracted could be as a result of long term 310
exposure to ultra violet radiation, enzyme degradation and sun light. This result is in 311
agreement with study by Balasubramanian et al. [26] where they found similar trend in fatty 312
acid content of lipids extracted from Nannachloropsis sp. using sun-drying. Both are 313
acceptable as ASTM recommendation for biodiesel. 314
High saponification values were observed in both sun dried and oven dried biomass oil. A 315
high saponification value from algal oil indicates that it can be used as efficient feedstock for 316
biodiesel synthesis. The high saponification and high acid values found in algal oil are 317
common to most non edible oils used for biodiesel production. This is in consistency with the 318
previous study by Veljkovic et al. and Zhang and Jiang, [28][29]. 319
The produced biodiesel was subjected to performance requirement properties. The properties 320
include Kinematic viscosity, Flash point and Cetane number. 321
Kinematic viscosity is one of the most important fuel quality parameter. Sun dried biomass 322
oil has higher viscosity than oven dried biomass oil. This could be due to higher degree of 323
saturated fatty acids in the sundried oil. Kelaiya, et al. [27] got similar results in their study of 324
fuel properties of Chlorella sp. for biodiesel. Biodiesel normally possessed superior 325
kinematic viscosity than fossil diesel. Findings show that Kinematic viscosity increases with 326
degree of saturations and carbon length and decreases with the degree of unsaturation [30]. 327
The flash point and cetane number of the sundried and oven dried Chlorella biomass 328
biodiesel were studied. Oven dried biomass biodiesel has a relatively higher flash point than 329
sun dried biomass biodiesel. However, there is no significant difference between the two 330
observed. Fuels above flash point of 66°C are considered safe fuel and are suitable for all 331
climatic conditions [24]. 332
The cetane number of the sundried biomass biodiesel was slightly higher than the cetane 333
number of oven dried biomass biodiesel. The significant dropped of the oven dried biomass 334
biodiesel cetane number could be due to effects of unsaturated fatty acid chains. The cetane 335
number decreases with unsaturation [30]. This result obtained was comparable with the 336
previous study by Bello et al., [31]. The fuel performance requirement properties obtained are 337
in agreement with the ASTM biodiesel standard. 338
Fatty acids composition has a profound effect on the fuel property of biodiesel. 339
In this study, fatty acid profile result had shown that there was variation in composition of 340
saturated fatty acids and mono-unsaturated fatty acids depending upon the drying technique. 341
Sun dried biomass oil had shown higher composition of saturated fatty acids than oven dried 342
biomass oil which possessed a balance of both saturated and unsaturated fatty acids. The high 343
composition of saturated fatty acids in the sundried biomass oil could be as a result of 344
oxidation of unsaturated fatty acids by sunlight or can be attributed to the desaturation effect 345
by enzyme degradation as indicated by Abhishek et al., [32]. The balanced for saturated and 346
unsaturated fatty acids confirms high quality product [32]. According to Knothe [33], the 347
most common fatty acid esters in biodiesel are C16:0, C18:0, C18:1, C18:2 and C18:3. This 348
is true for biodiesel feedstocks such as soybean, sunflower, rapeseed, palm and peanut oils 349
[33]. These findings were in agreement with those reported by Pratoomyot et al. [34]. Isik et 350
al. [35] reported C16:0, C18:0 +1 and C18:3 as the main fatty acid components in 351
Scenedesmus abundans. 352
A higher content of saturated fatty acids are desirable for better oxidation stability of 353
biodiesel. This is beneficial for industry as biodiesel could be stored for a longer period. On 354
the other hand, a higher content of unsaturated fatty acids is beneficial for cold flow 355
properties of biodiesel. This will lead to a possible usage of the fuel even in cold countries 356
and during the cold months. It is desirable that there is a mixture of both saturated and 357
unsaturated fatty acids in the oil so that both the oxidation stability and cold flow property 358
strike a balance (Abhishek et al., 2014). 359
5. CONCLUSION 360
Microalgae isolated from Kaduna State University fish pond was authenticated to be 361
Chlorella vulgaris. 362
The study showed that Sun and Oven drying techniques has no significant effect on the 363
quantity of oil produced from biomass of Chlorella vulgaris. 364
Sun drying technique at the temperature of 25-35ºC for 72hours has effect on the Acid value 365
(0.414), Kinematic viscosity (5.200), Cetane number (54.00) and composition of saturated 366
and unsaturated fatty acids, although both the sun and oven drying techniques quality value 367
were within the standard ASTM values recommended. Oven dried biomass oil was found to 368
be of high quality because of the balanced in saturated and unsaturated fatty acid 369
compositions (C14:0, C16:0, C19:0, C11:1, C18:1 cis9 and C22:1ω9). 370
371
REFERENCES 372
1. Sahoo P., Das L., Babu M. and Naik S. (2007). Biodiesel Development from High Acid 373
Value Polanga Seed Oil and Performance Evaluation in CI Engine. Fuel 86: 448-454. 374 2. Singh J. and Cu S. (2010). Commercialization Potential of Microalgae for Biofuels 375
Production. Renewable and Sustainable Energy Revolution 14: 2596–2610. 376
3. Yeh K. and Chang J. (2012). Effects of Cultivation Conditions and Media Composition 377 on Cell Growth and Lipid Productivity of Indigenous Microalga Chlorella vulgaris ESP-378 31, Bioresources Technology 105: 120–127. 379
4. Nigam P. S. and Singh A. (2010). Production of Liquid Biofuels from Renewable 380 Resources. Progress in Energy and Combustion Science. In press. DOI: 381
10.1016/j.pecs.2010.01.003. 382 5. Knothe G. (2010). Biodiesel and Renewable Diesel: A Comparison. Progress in Energy 383
and Combustion Science 36(3): 364-373. 384
6. Natural Ressources Canada (2011b). Initiative de démonstration nationale sur le diesel 385 renouvelable, In: Natural Ressources Canada, 23.05.2011, Retrieved from 386
2010/chap1.cfm?attr=16 388 7. Naik S., Goud V., Rout P. and Dalai A. (2010). Production of First and Second 389
Generation Biofuels: A Comprehensive Review. Renewable and Sustainable Energy 390 Reviews 14(2): 578-597. 391
8. Schenk P., Thomas-Hall S., Stephens E., Marx U., Mussgnug J., Posten C., Kruse O. 392 and Hankamer B. (2008). Second Generation Biofuels: High Efficiency Microalgae 393 for Biofuel Production 1: 20-43 394
9. Brennan L. and Owende P. (2010). Biofuels from Microalgae--A Review of Technologies 395 for Production, Processing, and Extractions of Biofuels and Co-products. Renewable and 396
Sustainable Energy Reviews 14: 557-577. 397 10. Fatih Demirbas M. (2009). Biorefineries for Biofuel Upgrading: A Critical Review. 398
Applied Energy 86(1): S151-S161. 399 11. Nigam P.S. and Singh A. (2011). Production of Liquid Biofuels from Renewable 400
Resources. Progress in Energy and Combustion Science 37(2): 52-68. 401
12. Chisti Y. (2007). Biodiesel from Microalgae. Biotechnology Advances 25: 294-306. 402 13. Li Y., Horsman M., Wu N., Lan C. and Dubois-Calero N. (2008) Biofuels from 403
15. Hirano A., Ueda R., Hirayama S. and Ogushi Y. (1997). CO2 Fixation and Ethanol 408 Production with Microalga Photosynthesis and Intracellular Anaerobic Fermentation. 409
Energy 22: 137–142. 410 16. Williams P. and Laurens L. (2010). Microalgae as Biodiesel and Biomass Feedstocks: 411
Review and Analysis of the Biochemistry, Energetics and Economics. Energy and 412 Environmental Science 3: 554-590. 413
17. Morweiser M., Kruse O., Hankamer B. and Posten C. (2010). Developments and 414
Perspectives of Photobioreactors for Biofuel Production. Applied Microbiology and 415
Biotechnology 87: 1291–1301. 416 18. Grzebyk D., Sako Y. and Berland B. (1998). Phylogenetic Analysis of Nine Species of 417
Prorocentrum (dinophyceae) Inferred from 18s ribosomal DNA Sequences, 418
Morphological Comparisons, and Description of Prorocentrum panamensis sp. nov. 419 Journal of Phycology 34(6): 1055–1068. 420
19. Ehimen E., Sun Z. and Carrington C. (2010). Variables Affecting the In situ 421 Transesterification of Microalgae Lipids. Fuel 89: 677–84. 422
20. Rwehumbiza V., Harrison R. and Thomsen L. (2012). Alum-induced Flocculation of 423
Preconcentrated Nannochloropsis salina: Residual Aluminium in the Biomass, FAMEs 424 and its Effects on Microalgae Growth upon Media Recycling. Chemical Engineering 425
Journal 200–202: 168–75. 426 21. Lee J., Yoo Jun S., Ahn C. and Oh H. (2010). Comparison of Several Methods for 427
Effective Lipid Extraction from Microalgae. Bioresources Technology 101(1): 575–7. 428
22. Bilal S., Mohammed-Dabo I., Nuhu M., Kasim S., Almustapha I. and Yamusa Y. (2013). 429 Production of Biolubricant from Jatropha Curcas Seed Oil. Academic Journal of 430
Chemical Engineering and Materials Science 4(6): 72-79. 431 23. Demirbas A. (2008). Relationships Derived from Physical Properties of Vegetable Oil 432
and Biodiesel Fuels. Fuel 87(8-9): 1743-1748. 433
24. Raja S., Smart D. and Lee C. (2011). Biodiesel Production from Jatropha Oil and its 434 Characterization. Resources Journal for Chemical Sciences 1(1): 81-87. 435
25. Reynaldo M. U. (2012). Identification of algal strains by PCR amplification and 436
evaluation of their fatty acid profiles for biodiesel production. (Master’s thesis, Louisiana 437 State University and Agricultural and Mechanical College). 438 https://etd.lsu.edu/docs/available/etd-01042012-150704/unrestricted/ Thesis.pdf. 439
26. Balasubramanian R., Yen-Doan T. and Obbard J. (2012). Factors Affecting Cellular Lipid 440
Extraction from Marine Microalgae. Chemical Engineering Journal 215–216: 929–36. 441
27. Kelaiya S., Chauhan P. and Akbari S. (2015). Fuel Property of Biodiesel made from 442 Microalgae (Chlorella sp). International Research Journal of Environmental Science 443 2320-8031. 444
28. Veljkovic V., Lakicevic S., Stamenkovic O., Todorovic Z. and Lazic M. (2006). 445 Biodiesel Production from Tobacco (Nicotiana tabacum L.) Seed Oil with a High Content 446
of Free Fatty Acids. Fuel 85(17-18): 2671-2675. 447 29. Zhang J. and Jiang L. (2008). Acid-catalyzed Esterification of Zanthoxylum bungeanum 448
Seed Oil with High Free Fatty Acids for Biodiesel Production. Bioresources Technology 449 99(18): 8995-8998. 450
30. Knothe G. (2005b). Viscosity of Biodiesel, In: The Biodiesel Handbook, Knothe G., 451
Krahl J. and Gerpen J. V., pp. 81-82 AOCS Press, Campaign, Illinois, USA 452 31. Bello E., Out F. and Osasona A. (2012). Cetane Number of Three Vegetable Oils, their 453
Biodiesels and Blends with Diesel Fuel. Journal of Petroleum Technology and 454 Alternative Fuels 3: 52-57. 455
32. Abhishek G., Bhaskar S., Ismail R., Krishan R. and Faizal B. (2014). Efficacy of Drying 456 and Cell Disruption Techniques on Lipid Recovery from Microalgae for Biodiesel 457 Production. Fuel 128: 46-52. 458
33. Knothe G. (2010). Biodiesel and Renewable Diesel: A Comparison. Progress in Energy 459 and Combustion Science 36(3): 364-373. 460
34. Pratoomyot J., Srivilas P. and Noiraksar T. (2005). Fatty Acids Composition of 10 461 Microalgal Species. Songlanakarin Journal of Science and Technology 27(6): 1179-1187. 462
35. Isik O., Sarihan E., Kusvuran E., Gul O. and Erbatur O. (1999). Comparison of the Fatty 463 Acid Composition of the Freshwater Fish Larva Tilapia zillii, the Rotifer Brachionus 464
calyciflorus, and the Microalgae Scenedesmus abundans, Monoraphidium minitum and 465 Chlorella vulgaris in the Algaerotifer-fish Larvae Food Chains. Aquaculture 174 (3): 466