Photobioreactor Review: Controlling malaria vector with Anabaena sp. strain PCC 7120 based a study by Ketseoglou & Bouwer. An optimization on the volumetric productivity was performed based on three factors described by the authors. This presentation serves just as a review for the authors' work but for education purpose only. All credit are due to the authors of the journal at http://www.sciencedirect.com/science/article/pii/S0168165613002381

1. KKKB 5933: ADVANCED BIOREACTOR ENGINEERING
BERNARD CHUNG KEN VUI
A98753
KB/4
Controlling malaria vector with
Anabaena sp. strain PCC 7120:
A study by Ketseoglou & Bouwer

2. INTRODUCTION: PHOTOBIOREACTOR
 Photobioreactor: specialized bioreactor that uses phototropic
microorganisms to generate bioproducts by using light as the main
energy source (Kunjapur & Eldridge 2010)
 Either in an open cultivation system (pond) or in the closed cultivation
system (Ketseoglou & Bouwer 2013)
 Closed systems include:
A) Flat plate
B) Bubble column
C)Tubular
Source: Posten 2009
 Potential bioproducts from phototropic microorganisms: Astaxanthin,
β-carotene, phycobiliproteins, biodiesel, jet fuel, and biofertilizer

3. INTRODUCTION: PHOTOBIOREACTOR
Arthrospira production plant in Calipatria, California
Source: Mostafa 2012

4. INTRODUCTION: MALARIA
 Malaria: An insect-transmitted disease
that remains one of the greatest global
health challenges of the modern era
(Oliva et al. 2013).
 Caused by Plasmodium falciparum
(parasite) and is transmitted by a bite
from an infected female Anopheles
mosquito (Janneck et al. 2011).
 The new technology to develop a
better insecticide has bring the
attention of using genetically
engineered cyanobacteria as
biopesticides for the control of
mosquitoes (Ketseoglou & Bouwer
2013).

5. INTRODUCTION: Bti TOXIN
 Biopesticide uses the highly toxic crystalline inclusions
produced by Bacillus thuringiensis subspecies israelensis (Bti)
 Endotoxin protein produced by Bti is commonly known as the
crystal protein (Cry) through Cry gene
 Disadvantages (Ketseoglou & Bouwer 2013):
 Possess low persistence in the field (inactivation by
ultraviolet)
 Problem due to ingestion by other aquatic organisms
 Settling from the mosquito larval feeding zone

6. INTRODUCTION: Bti TOXIN
Mode of action for Bt toxin crystal
Source: Jurat-Fuentes

7. CASE STUDY: OBJECTIVE
Optimization of photobioreactor growth conditions for a
cyanobacterium expressing mosquitocidal Bacillus thuringiensis
Cry proteins
By: Irene Ketseoglou, Gustav Bouwer
Link: http://www.sciencedirect.com/science/article/pii/S0168165613002381
 Cyanobacterium Anabaena sp. strain PCC 7120 has been genetically
engineered to express important Cry genes such as cry4Aa, cry11Aa
and p20
 Objective: To determine the optimal growth conditions for PCC
7120#11 in an indoor, flat-plate photobioreactor using RSM

8.  Cultivation of PCC 7120#11 till it reaches mid-exponential growth
 Introduced into the photobioreactor at initial cell concentration of
1.6 x 106 cells mL-1
 Experimental Designs:
 Flat-plate, inclined modular photobioreactor with two
toughened glass plates (6 mm thick, 702 mm length and 516 mm
height)
 Medium used: 3.7 L BG-11 for algae
 Temperature: 30 °C
 pH: 7.2
 Continuous illumination: 58 μmol m-2 s-1 with a panel of 8 Grolux
lamp
 Constant agitation: 140 rpm carbon dioxide-enriched air-bubble
mixing system
 Factors such as airflow, photosynthetic photon flux density (PPFD),
and CO2 affect the growth and development of cyanobacteria
 Response is on the volumetric productivity of PCC
CASE STUDY: METHOD

9. CASE STUDY: FINDINGS
Effect of input CO2 concentration and airflow rate at low
PPFD (53.0 μmol m-2 s-1) on the volumetric productivity

10. CASE STUDY: FINDINGS
Effect of airflow rate and PPFD on PCC 7120#11 volumetric productivity
at a input CO2 concentration of 3.75% (v/v)

11. CASE STUDY: FINDINGS
1. Prediction equation:
2. Numerical optimization reveals that the highest volumetric
productivity of 0.47 g L−1 d−1 were predicted to be a PPFD of 154
μmol m−2 s−1, an airflow rate of 1.02 vvm and an input CO2
concentration of 3.18 % (v/v).
3. For commercialization where cost of production is the main
objective, numerical optimization reveals that optimal volumetric
productivity of 0.44 g L−1 d−1 were obtained at a PPFD of 139.66
μmol m−2 s−1, an airflow rate of 1.00 vvm and an input CO2
concentration of 1.50 % (v/v)
4. Larvicidal activity: Mean of LC50 as reported for the runs was 9.24 x
105 cells mL-1
2
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CBCAB
CBAoductivity
...
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


12. CASE STUDY: CONCLUSIONS
Source Ketseoglou &
Bouwer 2013
Yoon et al. 2008 Fontes et al.
1987
Yu et al. 2011
Type of
photobioreactor
Flat-plate Bubble
(Annular)
Airlift Airlift
Parameters
studied
PPFD, CO2 input,
Airflow rate
Superficial gas
velocity, pH,
Initial
phosphate
concentration,
Light intensity
Airflow rate,
Light density
Mixotrophic
culture
Productivity 0.47 g L−1 d−1
(maximum)
0.44 g L−1 d−1
(optimum)
0.67 g L−1 d−1
(optimum)
13 g m−2 d−1
(optimum)
0.43 g L−1 d−1
(optimum)
Comparisons of different findings on the characterization and design studies

13. THE FUTURE
1. Future PCC 7120#11 studies may want to determine if volumetric
productivity has an impact on the ratio of the LC50 of late-
exponential phase cells to the LC50 of mid-exponential phase cells.
2. A comparison of the different studies suggests that PCC 7120 may
have a lower volumetric productivity maximum than other
cyanobacteria
3. Provide a foundation for future continuous culture optimization
experiments, in which key process parameters are monitored and
controlled on a continual basis
4. Extensive scale-up studies are necessary to evaluate the feasibility
of commercial-scale production of PCC 7120#11