UTILIZATION OF PLANT LIPASE FOR SMALL PRODUCTION SCALE PROCESS OF FATTY ACID

• Main Author: Nur Istyami, Astri
• Format: Dissertations
• Language: Indonesia
• Subjects: Teknik kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/38764
• Institution: Institut Teknologi Bandung

Free fatty acid is an important intermediate product in oleochemical industry. Aside from being converted into oil and fats derivatives, fatty acids can also be processed into drop-in biofuel. This kind of biofuel is readily applied in automotive engine without the necessity of blending with fossil fuel. The current fatty acids production technology requires huge amount of energy and causes unwanted side reactions. Triglyceride hydrolysis can alternatively be done with lipase enzyme, a reaction that is also known as lipolysis. This process is potentially more economic than the conventional one because it feasibly operates in mild operating condition and cause less product deterioration. Due to high production cost of microbial lipase, plant seeds and plant latex became a low-cost alternative source of lipase. Activity of several plant lipases have been reported before, but usually they require very high ratio of crude lipase to substrate, very high ratio of organic solvent to substrate, or very long reaction period. The general objective of this research is to develop fatty acid production technology in mild condition process with utilization of plant lipase. To obtain process with good feasibility, performance of various plant-based lipases was evaluated. Evaluation was conducted for 16 plant lipases, i.e. physic nut (Jatropha curcas), castor seeds (Ricinus communis), kapok seeds (Ceiba pentandra), wild almond seeds (Sterculia foetida), pongam seeds, (Milletia pinnata), sea mango seeds (Cerbera manghas), red poon seeds (Calophyllum inophyllum), roda seeds (Hura crepitans), red lucky seed (Adenanthera pavonina), rubber seeds (Hevea brasiliensis), rice bran (Oryza sativa), aveloz latex (Euphorbia tirucalli), plumeria latex (Plumeria sp.), sea mango latex (Cerbera manghas), papaya latex (Carica papaya), and jackfruit latex (Artocarpus heterophyllus). Among the lipase source evaluated, frangipani latex lipase performed highest degree of lipolysis at low crude lipase content (1%-substrate) and with the absence of organic solvent. To enhance process feasibility, variable optimization of lipolysis with frangipani latex was conducted. Evaluated variables were pH, temperature, organic solvents to oil ratio, water to oil ratio, lipase particulate size, activator ion addition, and crude lipase storage period. The effects of each variables were quantified to screen variables with highest impact to degree of hydrolysis. Optimization was then established with Response Surface Method. Performance of frangipani latex lipase was optimum on pH 8.25, where degree of lipolysis achieved 74.5% in 10 hours reaction. To increase process efficiency, immobilization was conducted to frangipani latex lipase. Immobilization is enzyme attachment onto a support surface or into a matrix to enable recycling of enzyme. In this research, immobilization of frangipani latex lipase was conducted with adsoprtion method (onto surfaces of rice bran acetone powder, polypropylene beads and polyethylene beads) and encapsulation ethod (into calcium alginate matrix). Immobilization with adsorption method, although was effective for liquid microbial enzyme, was proved not to be effective for frangipani latex particulate lipase. Immobilization with encapsulation method, although was more effective than using adsorption method, prone to breaking of matrix which leads to product contamination, especially in stirred tank reactor. Considering performance and availability between free (unimmobilized) lipase and immobilized lipase, lipase in free form was recommended in utilization of frangipani latex lipase. The last part of this research was kinetic study of plant oil lipolysis using frangipani latex lipase. Based on the assumption that lipolysis was occurred in one-step conversion, several models based on Michaelis-Menten equation were proposed: simple Michaelis-Menten model, Michaelis-Menten model with effect of emulsion area surface, Michaelis-Menten model with effect of water volume fraction, and Michaelis-Menten model with effect of product inhibition. Three-step conversion model was also proposed by considering that lipolysis was involving formation of diglyceride an monoglyceride, using MATLAB® Simulink software. Although the one-step conversion models acknowledge the effects of factors such as emulsion, water amount, and product inhibition, the three-step conversion model demonstrates better fits to experimental data. This model can be applied to estimate the degree of lipolysis with adequate accuracy or extended further to estimate accurately the various kinetic consstants involved, if data on concentrations of diglycerides and monoglycerides formed along the reaction are available or measured.