2010 IBE Transesterification of Intracellular Lipids Using a Single Step Reactive-Extraction

8/8/2019 2010 IBE Transesterification of Intracellular Lipids Using a Single Step Reactive-Extraction

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Daniel Nelson1, Ron Sims1, Sridhar Viamajala2Utah State University1, University of Toledo2

Transesterification ofIntracellular Lipids Using a

Single Step Reactive-Extraction


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Utah State University

Microorganism derived biodiesel

Accumulated as intracellular lipids

% of cell lipid content

Type of fatty acid (C14,C16, C18)

How/what/where to obtain biomass

Algae, fungi, etc?

Autotrophic, heterotrophic?

Pond, photo-bioreactor?

http://apexlyo.com/attachments/Image/algae.jpg


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Extraction-Transesterification

Chemical (Bligh and Dyer)

Mechanical

Followed by transesterification

Other

Super critical fluid (SFE),

microwave assisted

In-situtransesterification

Reduces steps/time


How to get the biodiesel out?

http://img170.imageshack.us/

img170/5990/palmeb8.jpg


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Derive a model using known reaction mechanismsto describe the in-situtransesterification of TAGs toFAMEs that is scale independent and can be usedfor large scale production


Objective


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Schizochytrium limacinumSR 21(ATCC MYA 1381), marine fungus

High Lipid Content: 40-50% (dry basis), grow on glycerol


Organism Selection

Fatty Acid Fraction: (% w/w) of Total Lipid

14:0 15:0 16:0 22:5, 22:6

Reference Myristic Pentadecanoic Palmitic DPA + DHA

Yokochi et al., 1998 2.7 7.6 34.2 51.7

Chi et al., 2007 4.0 nr 52.0 42.0

This Study 3.80.11 2.50.08 53.91.3 40.12.5

DPA = Docosapentaenoic acid, DHA = Docosahexaenoic acid, nr = not reported


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In-situ reaction

In-situ transesterification reaction experiments:

Studied significant factors, Acid & Biomass conc.

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140 160 180

ConcentrationofFAME(mgmL-1)

Time (min)

66mg/ml

125mg/ml

200mg/ml

250mg/ml

0

5

10

15

20

25

30

35

0 10 20 30 40 50 60 70 80 90

ConcentrationofFAME(mg/mL)

Time (min)

5%

2%

1.5%

1%


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Using the fundamentalreaction mechanism:

We establish thefollowing identities:

S = TAG

S = Methanol

Model Development

Meher 2006


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We derive the rate expressions:

Model Development

Where:

[S] = specific stable TAG concentration at any time during the reaction (mg-TAGml-1 Methanol

[H+

] = specific stable H+

concentration at any time during the reaction (mg- H+

ml-1

-Methanol[S] = is assumed to be constant throughout the reaction

[SH+] = specific stable TAG-H+ complex at any time during the reaction (mg- TAG-H+ ml-1- Methanol

[SSH+] = specific stable TAG-H+-MeOH complex at any time during the reaction (mg- TAG-H+-MeOHml-1 - Methanol


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Since the first 2 reactions areassumed to be reversible, theequilibrium constants can be

written as:

Model Development

And:


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Model Development

Through substitution of variables, and solving for overall H+ balances,we can reassign the constant terms to single variables Vm and km:

Under our conditions, S was much greater than S, and is assumed to

be constant. Also, Vm and km can be treated as constant when using a

fixed acid conc. In terms of these constants, the rate equation for fattyacid formation can be written as:


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Fatty acid production measured over time as a function of biomass

Data Modeling

Vm = 1.43 mg ml-1 min-1 km = 23.15 mg ml-1


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Since km is independent of acid concentration, Vm was determinedat various acid concentrations. From the expression of Vm, thisparameter should be directly proportional to the initial acid conc.

Model Verification


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An accurate model was developed to describe the in-situ

transesterification reaction based on the known reaction mechanism

The model thus developed is scale-independent and may be appliedto the design of large scale reactors


Conclusions


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Sridhar Viamajala, Biological Engineering, University of Toledo

Ronald Sims, Biological Engineering, Utah State University

Biological Engineering Program, Utah State University


Acknowledgments


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Bligh E, Dyer W. A rapid method of total lipid extraction and purification. Canadian Journal of Biochemistryand Physiology (1959) 37: No. 8, 911-917

Carrapiso A., Garcia C. Development in Lipid Analysis: Some New Extraction Techniques and in situTransesterification. Lipids (2000) Vol. 35, no11, 1167-1177

Lewis T, Nichols P, McMeekin T. Evaluation of extraction methods for recovery of fatty acids from lipid-producing microheterotrophs. Journal of Microbiological Methods (2000) 43: 107-116

Yokochi T, Honda D. Optimization of docosahexaenoic acid production by Schizochytrium limacinumSR21. Appl. Microbiol. Biotechnol. (1998) 49: 72-76

Meher, L.C., Sagar D. Vidya, Naik S.N. Technical aspects of biodiesel production by transesterification- areview. Renewable and Sustainable Energy Reviews. (2006) Vol. 10 Issue 3, 248-268

Mortia E., Kumon Y. Docosahexaenoic acid production and lipid body formation in Schizochytriumlimacinum SR21. Marine Biotechnology (2006) 8; 319-327

Chi Z, Pyle D, Wen Z, Frear C, Chen S. A laboratory study of producing docosahexaenoic acid frombiodiesel-waste glycerol by microalgal fermentation. Process Biochemistry (2007) 42: 1537-1545

Pyle D, Garcia R, Wen Z. Producing docosahexaenoic acid (DHA)-rich algae from biodiesel-derived crudeglycerol; Effects of impurities on DHA production and algal biomass composition. J. Agric. Food Chem.(2008) 56; 3933-3939

References



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Thank You.

Questions?


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GC Chromatograms

TAGs extracted

from biomass,internal standard

FAMEs, converted

from TAGs, noTAG remains afterin-situtransesterification


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Model Development

Documents

2010 IBE Transesterification of Intracellular Lipids Using a Single Step Reactive-Extraction