Carbon capture and storage (CCS) involves capturing, transporting and storing CO2 geologically underground permanently. Carbon capture using solvent such as amine and aqueous ammonia has been extensively studied by many researchers. However, this capture technology for CCS scheme is costly. As an alternative, CO2 emission can be cost-effectively captured and stored by utilizing the well-understood natural photosynthetic process of marine cyanobacteria. In contrast, the capturing process using cyanobacteria is very slow compared to the chemical absorption mentioned prior. Hence, this study aimed to investigate carbon capturing and storing process using integrated aqueous ammonia and mutated marine cyanobacteria (Synechococcus PCC 7002 IIUM01). The conditions that can maximize CO2 reduction under various conditions; CO2 flow rate (Lpm), absorption temperature (C) and aqueous ammonia concentrations (% (w/v)) were to be identified. The effectiveness of the mutant cyanobacteria was quantified by measuring the cell concentration, percentage reduction in CO2 concentration and lipid content. Synechococcus PCC 7002 IIUM01 showed it robustness by growing in aqueous ammonia solution at the concentration of 0.5 to 1% (w/v) at which the parent strain was not able to tolerate. The best conditions in maximizing CO2 capture and storage while sustaining growth optimally and being a potential biofuel source was observed at 0.5 Lpm of 15% CO2 gas flow rate, 0.75% (w/v) of ammonia concentration and 33C of absorption temperature. At this specified condition, around 68% of CO2 removal was achieved with 9% (w/w) yield of lipid and more than 13% (w/v) of cell concentration obtained.
Citrus is one of the major commodities in many countries including Malaysia.
However, production of citrus including Citrus suhuiensis (C. suhuiensis) is declining due to
diseases and inability to withstand low temperatures. Plant cultures such as cell suspension have the
potential in propagating disease-free and healthy Citrus fruits with value-added characteristics.
However, studies related to C. suhuiensis is still scarce. Therefore, the growth kinetics of C.
suhuiensis cell suspension culture was studied. Friable callus of C. suhuiensis which was induced
from seeds was inoculated into MS medium with 30 g/L sucrose, 0.5 g/L malt extract and 2.0 mg/L
2, 4-D for the cell suspension initiation. Several batch experiments using a few types of sugars
(sucrose, glucose and fructose) were carried out. The cell dry weight (CDW) of C. suhuiensis was
recorded for 30 days of culture period and residual sugars in the medium were analyzed using
HPLC. Cells grown in 30 g/L sucrose achieved the highest CDW (9.559 g/L) with µmax equals to
0.00512/h, compared to glucose and fructose. In addition, sucrose is the preferred carbon source
with the highest uptake rate (0.213 g/L·h). Cells completely hydrolyzed sucrose into glucose and
fructose after 5 days of inoculation. All sugars were completely utilized by C. suhuiensis cells after
25 days. The kinetic growth parameters determined from batch experiments were then used for
model simulation and verification in MATHCAD 15. After adjustments and refinement to the
selected kinetic parameters, the model has fairly described and predicted the growth and sugars
profile of C. suhuiensis cells. The proposed model can be used to predict sucrose hydrolysis, glucose
and fructose formation from sucrose and their consumption by plant cells and also for larger scale
of growth.