Study On Catalyzed Hydrolysis Of Castor Oil By Candida Rugosa Lipase In Simple AOT Microemulsion And AOT/TritonX-100 Microemulsion Systems

The hydrolysis activity of Candida rugosa lipase by using castor oil as the substrate were studied in simple AOT reverse microemulsion system and in AOT/Triton X-100 mixed reverse microemulsion system. The effects of molar fraction of TritonX-100 to total surfactants(x), molar ratio of water to total surfactants(ω₀), reaction temperature, pH and the concentration of enzyme in "water pool" and substrate on enzymatic activity were investigated. It is found that the activity of Candida rugosa lipase increases rapidly with x up to 20%. Maximum enzyme activity appears at 307.15-311.15 K, pH=6.8 andω₀=6-7 in simple AOT reverse microemulsion system and at 307.15 K, pH=7.0,ω₀=5-6 in AOT/TritonX-100 mixed reverse microemulsion system (x=20%), respectively.The activation energy, the Michaelis constant K_m,a ,the maximum enzyme activity(v_max) and the catalytic rate constant(K_cat) of the reaction were calculated in both reaction systems. It is seen that the activation energy of the reaction in reverse microemulsions with and without Triton X-100 is almost identical,whereas v_max and K_cat increase significantly and K_m,a increases appreciably in the AOT/TritonX-100 mixed reverse microemulsions system. The stabilities of the enzyme in microemulsions were also determined and discussed.