BIOMASS CULTIVATION OF Chlorella vulgaris in POLYETHYLENE PHOTOBIOREACTORS WITH VARYING DIAMETER, LIGHT INTENSITY
AND AERATION RATE
ELMER BRENT TATEL CAUTON
SUBMITTED TO THE FACULTY OF THE
COLLEGE OF ENGINEERING AND AGRO-INDUSTRIAL TECHNOLOGY UNIVERSITY OF THE PHILIPPINES LOS BAŇOS
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE
DEGREE OF
BACHELOR OF SCIENCE IN CHEMICAL ENGINEERING
APRIL 2009
The thesis attached hereto, entitled “BIOMASS CULTIVATION OF Chlorella vulgaris IN POLYETHYLENE PHOTOBIOREACTORS WITH VARYING DIAMETER, LIGHT INTENSITY AND AERATION RATE” prepared and submitted by ELMER BRENT TATEL CAUTON in partial fulfillment of the requirements for the degree of Bachelor of Science in Chemical Engineering, is hereby accepted.
______________________________________ _______________________________
Engr. MARIA CHRISTINA V. MAHILUM Dr. CATALINO G. ALFAFARA
Panel Member Panel Member
___________________ __________________
Date Signed Date Signed
_________________________________ _______________________________
Prof. JUNE OWEN O. NACORDA Prof. REX B. DEMAFELIS Co-Adviser Adviser
___________________ __________________
Date Signed Date Signed
__________________________________
Dr. JOVITA L. MOVILLON Chair
Department of Chemical Engineering ____________________
Date Signed
___________________________________
Dr. ARSENIO N. RESURRECCION Dean
College of Engineering and Agro-Industrial Technology University of the Philippines Los Baños
_____________________
Date Signed
TABLE OF CONTENTS
CHAPTER PAGE
NUMBER
TITLE PAGE i
ACCEPTANCE SHEET ii
ACKNOWLEDGEMENT iii
TABLE OF CONTENTS vi
LIST OF TABLES viii
LIST OF FIGURES ix
ABSTRACT xi
I. INTRODUCTION 1
1.1. Significance and Background of the Study 1
1.2. Objectives of the Study 4
1.3. Scope and Limitations of the Study 4
1.4. Time and Place of the Study 5
II. REVIEW OF RELATED LITERATURE 6
2.1. Chlorella vulgaris Alga 6
2.2. Chlorella vulgaris Oil 10
2.3. Biodiesel 12
2.4. Cultivation of Microalgae 14
2.4.1. Photobioreactors 14
2.4.2. Microalgal Pond Systems 15
2.5. Factors Affecting Microalgal Growth 17
2.5.1 Light Intensity 17
2.5.2 pH 17
2.5.3. Reactor Diameter and Geometry 18
2.5.4. Aeration Rate 18
2.5.5. Medium 19
2.6. Studies on the Factors Affecting Microalgal Growth 19 2.7. Cell Density, Biomass and Optical Density Relationship 20
2.8. Growth Rate 21
III. MATERIALS AND METHODOLOGY 22
3.1. Microalgal Culture 22
3.2. Media Preparation and Sterilization 22
3.2.1. Preparation of Culture Media 22
3.2.2. Sterilization of Culture Media 24
3.3. Preparation of Inoculum 25
3.4. Experimental Setup 25
3.5. Cultivation of Chlorella vulgaris 30
3.6. Sampling 30
IV. RESULTS AND DISCUSSIONS 32
4.1. Cultivation of Chlorella vulgaris 33
4.1.1. Growth of Chlorella vulgaris in Highly-Aerated Systems 33 4.1.2. Growth of Chlorella vulgaris in Low-Aeration Systems 40
4.2. Statistical Analysis 47
V. SUMMARY AND CONCLUSIONS 50
VI. RECOMMENDATIONS 53
REFERENCES 54
APPENDICES 56
A. Raw Data 56
B. Growth Curves of Chlorella vulgaris for Trial 2 60 C. Specific Growth Rates of Chlorella vulgaris under 0.896vvm 62 D. Specific Growth Rates of Chlorella vulgaris under 0.242vvm 68
E. Sample Calculations 74
F. Material Safety Data Sheet 77
LIST OF TABLES
TABLE TITLE PAGE NUMBER
2.1 Chemical Composition of Some Algae Expressed on a 8 Dry Matter Basis (%)
2.2 Selected Microalgae with their Maximum Lipid Content (%w/v) 9
2.3 Hydrocarbon Distribution of Algal Oil 11
2.4 Biodiesel Properties of Petrol-derived and Micralgal Biodiesel 14 3.1 BG11 Culture Media Components and Amounts in Stock Solution 22 4.1 Culture Conditions Studied in the Cultivation of Chlorella 32
vulgaris
4.2 Specific growth rates (hr-1) of Chlorella vulgaris under 36 high aeration rate
4.3 Doubling time (hr) of Chlorella vulgaris in high aeration 39 systems with varying diameter and light intensity
4.4 Specific growth rates (hr-1) of Chlorella vulgaris under 43 low aeration rate
4.5 Doubling time (hr) of Chlorella vulgaris in low aeration 46 systems with varying diameter and light intensity
4.6 Summary of the statistical analysis of cultivation parameters 47 on the doubling time of Chlorella vulgaris using three-way
ANOVA via Design Expert v.7.1.6
LIST OF FIGURES
FIGURE TITLE PAGE NUMBER
2.1 Chlorella vulgaris cells in suspension and photomicrograph 6
2.2 Sample of a Triglyceride Molecule 13
2.3 Schematic Representation of a Raceway Pond 16
3.1 Beer amber bottle used for media sterilization 23
3.2 BG11 Culture Media stored in boxes 24
3.3a Schematic Representation of the Experimental Setup 25
3.3b Actual Experimental Cultivation Setup 26
3.4 Side View of the Cultivation Setup 26
3.5 Reactors Used in the Cultivation of Chlorella vulgaris 27
3.6 Precision PR7500 air pump 28
3.7 Vespa Compressor and Galvanized Iron nipple and elbow 29 used in aeration of Reactor 3
3.8 Hach DR 2800 Visible Spectrophotometer 31
3.9 Hach COD Vials and Syringe used in algal sampling 31 4.1 Growth curves of C. vulgaris in photobioreactors under 34
High Aeration Rate (Trial 1)
4.2 Effect of increasing light intensity to specific growth rate 37 for the photobioreactors aerated at 0.896vvm
4.3 Effect of increasing reactor diameter to specific growth rate 38
for the photobioreactors aerated at 0.896vvm
4.4 Growth curves of C. vulgaris in photobioreactors under 41 Low Aeration Rate (Trial 1)
4.5 Effect of Increasing light intensity to specific growth rate 44 for the photobioreactors aerated at 0.242vvm
4.6 Effect of increasing reactor diameter to specific growth rate 45 for the photobioreactors aerated at 0.242vvm
