GROWTH KINETICS OF Citrus suhuiensis CELL SUSPENSION CULTURES

Abstract

Citrus is as one of the major commodities in most countries because of its demand and availability throughout the year. However, production of citrus including Citrus suhuiensis (C. suhuiensis) is declining due to diseases and unable to withstand low temperature. Plant cultures such as cell suspension has a potential in propagating free-disease 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 several 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 the residual sugars in medium were analyzed using HPLC. Cells were completely hydrolyzed sucrose into glucose and fructose after 5 days of inoculation. All sugars were completely utilized by C. suhuiensis cells after 25^th day. The kinetic growth parameters determined from batch experiments were then used for model simulation and verification in MATHCAD 15 software. After adjustments and refinement to the selected kinetic parameters, the model has fairly described and predicted the growth and sugars profile of C. suhuiensis cell suspension culture. The proposed model can be used to predict sucrose hydrolysis, glucose and fructose formation from sucrose and their consumption by the cells and also for larger scale of growth.