PAPER REVIEW

Effect of oxygen concentration on the growth

of Nannochloropsis sp. at low light intensity.

Name : Vijendren Krishnan

Supervisor : Prof. Dr. Yoshimitsu Uemura

Date : 16 July 2014

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INTRODUCTION

CO2, nitrogen and phosphate content have

been known to influence growth and lipid

production

Oxygen may cause deleterious effect to

microalgae especially in tubular PBR.

Photorespiration & Photo-inhibition may

decrease the microalgae growth

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CALVIN CYCLE

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CHANGE IN MECHANISM

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EXPERIMENTAL

Culture condition:

Light : 18:6hr, 41 µmol photon m-2 s-1 (Red LED,

637nm)

pH : 7.8

CO2 : 2%

Flow rate : 0.5 L/min

Medium : Zou medium

PBR : Flat panel PBR

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ZOU MEDIUM

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EXPERIMENTAL

Manipulated: Dissolved oxygen (air saturation):

25, 50, 75, 100, 125, 150, 175, 200, 250, 300%

Responding :

* Oxygen evolved (photosynthetic rate)

liquid phase oxygen electrode chamber

* Biomass dw pre-weight glass microfibre

filter, washed with ammonium formate (O.5M)

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RESULT AND DISCUSSION

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Figure 2 : A typical growth curve of Nannochloropsis sp. During the batch run in a 1.5-L

flat-panel photobioreactor, followed by the turbidostat run at dissolved oxygen (DO)

concentration ranging from 20 to 100% air saturation; a batch, b 100% DO, c 75% DO, d

50% DO, e 25% DO, f 20% DO 10

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100% C1.77O0.24N0.15

300% C1.72O0.24N0.15

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Table 2: of oxygen effects on growth of Nannochloropsis sp. At different oxygen

concentrations

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CONCLUSION

An increase of the oxygen concentration from

20 to 75% air saturation showed no obvious

effect of oxygen concentration on specific

growth rate.

To improve the productivity of Nannochloropsis

sp. the oxygen level needs to be controlled.

Synergetic effects of high irradiance and oxygen

on growth for optimization of productivity in the

closed photobioreactors need to be

investigated..14