99-125 Lipase Of Candida In The Reverse Micelle System Synthesis Of Biodiesel

Biodiesel production catalyzed by lipase shows many advantages as a material-processing-product green technology.In that process,however,lipase has a low solubility in the substrates(oil)and alcohols which leads to less activity of lipase and low conversion rate.Candiada sp.99-125 lipase was used in bis(2-ethylhexyl)sulfosuccinate(AOT) reverse micelles system to produce biodiesel from soybean oil.The effects of various factors on reaction including the nature of solvents,concentration of AOT,ratio of water and AOT,buffer pH,temperature,methanol adding steps and rotating speed were studied.Results showed that AOT reverse micelles system provided a suitable micro-environment for biodiesel production.The optimal parameters were W₀ (defined as the mass ratio of water to surfactant)11,AOT concentration 50 mmol/L, temperature 40℃,buffer pH 7,the ratio of methanol and oil 3,and rotating speed 180 r/min.The conversion rate can reach 90%when a three steps methanolysis protocol was used.To shorten transesterification time of biodiesel production,the esterification of palmitic acid with methanol catalyzed by Candida sp.99-125 lipase in AOT reversed micelles was studied.The optimum conditions were as follows:W₀ 7,molar ratio of methanol and palmitic acid 2.The conversion rate reached 92%after an hour.Under such conditions,the kinetic studies indicated that the reaction followed a Ping-Pang Bi Bi mechanism and kinetic parameters were determined to be V_max=3.94*10^-8mol.L^-1,min^-1.mg^-1,K_{mpalmaticacid}=0.4901 mol/L,K_mmethanol=0.1055mol/L.The production of biodiesel catalyzed bu lipase from TongZi oil in SAPN and AOT reverse micelles systems was optimized using Orthogonal experiment and JMP software.The results proved the kind of surfactants and alcohols step-wise have distinct effect on conversion rate.The formula for biodiesel production was obtained and coefficient R² was 0.93.The reuse of lipase and reversed micelles systems were also investigated.The results showed that hydrolysis of oil was kept in reversed micelles under suitable mico-enviroment,then methanol was added in the reaction by many steps,the activity of lipase can continued 74hours,while the conversion rate can reach to 83%.yield efficiency of lipase 0.79g/10mg.