แบบจำลองทางคณิตศาสตร์ของการสกัดสารไฟโคไซยานินความบริสุทธิ์สูงจากสาหร่ายสไปรูลินา

Abstract

C-Phycocyanin (CPC) is a high-value bioproduct created by blue-green algae Spirulina platensis. It is widely used in various industries, such as, in food pharmaceutical and cosmetics industries. This study aimed to develop a high purity C-phycocyanin extraction process from the upstream (farming) to the middle stream (processing), of spirulina chain production to produce high purity CPC extracts to develop into further products. The fed-batch cultivation was applied as a strategy to enhance growth and CPC accumulation. In this study, Spirulina platensis was cultured in the batch and fed-batch to investigate CPC production. On batch cultivation, it was found that increasing nitrogen source concentration led to an increase in CPC accumulation. The maximum CPC concentration (2.258 g/L) occurred when NaNO3 was 3.5 g/L. The results indicate that the maximum CPC production (4.354 g/L) and productivity (97.53 mg/L·d) were obtained when using fed-batch with the NH4HCO3 2.0 mM. Kinetic model to describe the Spirulina platensis culture system, including cell growth, CPC formation, as well as nitrogen consumption, was proposed and found in good agreement with the experimental results. It can be employed to predict the production of biomass, CPC, and the consumption of nitrogen in culture. For extraction, The Aqueous Two-Phase Extraction (ATPE) is to purify of CPC extract was studied. The polyethylene glycol and potassium phosphate were used to purify CPC. Also, the effect of temperature differences with the ATPE process was applied to improve the efficiency of purification. The influence of various temperature gradient (TG) of process on purity (EP) partitioning and diffusion coefficient were evaluated. The optimal conditions for CPC purification was found at TG25. The CPC purity increased to 2.337 from an initial purity of 1.106. The concentration and recovery yield reached highest value with TG25 (13.932 g/L and 91.18, respectively), which were significantly higher than those of the conventional process. The TG necessarily affected the fluid viscosity variable, possibly due to a decrease in viscosity of the mixture, and increases in the solvent solubility and diffusion capacity. The isothermal diffusion coefficient (Di) significantly increases with TG. The Soret effect (ST) and thermal diffusion coefficient (DT) was obtained at the high TG, but it should be less than 25. A mathematical model of CPC purification using ATPE method at constant temperature conditions. (Conventional method) and ATPE on the temperature gradient process was studied to explain the behavior of the phase separation of the process. The chemical potential was an indicator of a system, when the system reaches equilibrium. The chemical potential in both the upper and lower phases have the same. The mathematical model can predict the partition coefficient and purity of the extract with the error less than 10%. Finally, ATPE on the temperature gradient prototype concept design was proposed The investment of ATPE extractor was approximately 1,200,000 Bahts. To produce the pure CPC as powder with capacity of 1,200 g/days. The result found that the simple payback period for the extractor was about 2 year.