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Effect of elevated level of CO2 on Kirchneriella sp., a microalga, under salinity and nitrogen stress.

IR@CSIR-CFTRI

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Relation http://ir.cftri.com/11566/
 
Title Effect of elevated level of CO2 on Kirchneriella sp., a microalga, under salinity
and nitrogen stress.
 
Creator Kamala, Shiny. S
 
Subject 01 Algae
 
Description The present study is focused on the effect of stress conditions in microalga Kirchneriella sp
which was grown under ambient (0.03%) and elevated level of CO2 (20%) . The stress
condition selected was nitrogen at 0.008 M, 0.004 M and 0.0017M of NaNO3 and salinity at
0.04M, 0.085M, 0.127M and 0.17M NaCl. The cellular metabolites were studied in the
culture under these conditions. Biomass yield clearly indicate the growth promoting and
salinity stress alleviating effect of 20% CO2 up to 0.13M level of NaCl in medium. The
cultures under all the tested levels of nitrogen stress showed no significant increase in the
biomass yields with ambient level of CO2. The total chlorophyll content under salinity stress
shows that under ambient level control culture and cultures under 0.04 M and 0.13 M NaCl
was in the range of 22-30 μgm/ml and under elevated level the cultures under 0.08 M and
0.13 M NaCl show comparatively lower chlorophyll content. The total chlorophyll content in
nitrogen stress under supplementation with 20% CO2 was about 22-24 μgm/ml which is
almost two fold increase than the chlorophyll content achieved under ambient level of CO2.
There was also increase in carotenoid content. Total lipid content of the microalga was also
estimated as a function CO2 . Under elevated levels of CO2, the lipid content of all the
cultures at all the tested levels of NaCl showed an enhancement of lipid content. Total lipid
content with nitrogen stress suggested that reduced nitrogen level lead to an increase of lipid
content by about 12% over control cultures under ambient level of CO2 and on
supplementation with elevated levels of CO2, there was a 34% increase in lipid content in
control culture. Fatty acid profile of the cultures indicated that ambient level was favourable
for accumulation of unsaturated fatty acids.
The enzyme Carbonic anhydrase (CA) is an important component of carbon concentrating
mechanism. Its activity was measured in cultures under nitrogen stress (supplied with
nitrogen at 0.004M NaNO3) under ambient and elevated levels of CO2. Supply of CO2 led to
decrease in culture pH, availability of free CO2 and decreased levels of bicarbonate in culture
medium. The activity of carbonic anhydrase in elevated CO2 supplied cultures is higher than
the cultures supplied with ambient level of CO2.
 
Contributor Sarada, R.
 
Date 2013
 
Type Student Project Report
NonPeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://ir.cftri.com/11566/1/shiny%20thesis.pdf
Kamala, Shiny. S (2013) Effect of elevated level of CO2 on Kirchneriella sp., a microalga, under salinity and nitrogen stress. [Student Project Report] (Submitted)