Abstract
In this research, it was found that in Yarrowia lipolytica Lipase 2 (YLLIP2)-catalyzed biodiesel production, the content of fatty acid methyl esters (FAMEs) was increased by about 10% with the addition of d(+)-glucose. The result indicated that the d(+)-glucose could be used as an effective additive in YLLIP2-catalyzed biodiesel production. In accordance with the results above, the single factor experiments of key parameters in the process were first carried out. On the basis of the single factor experiment results, a five-factor, three-level response surface method was adopted to obtain the optimal reaction conditions: lipase dosage 40 IU/g oil, d(+)-glucose to lipase 1:1.05 (w/w), water content 1.95%, and reaction temperature 39.4 °C. A stoichiometric amount of methanol (11.5%, methanol/waste oil) was added in 6 times (every 4 h for each addition). A subsequent pilot scale production in a 5-ton reactor was carried out to check the performance of this method, and a good biodiesel content of 91.4% was obtained. Finally, molecular dynamics (MD) simulation was adopted to help to explain the possible functions of d(+)-glucose acting on the lipase in the process. The simulation results indicated that one of the functions may be attributed to d(+)-glucose preventing methanol to diffuse into YLLIP2, thus resulting in the prevention of the methanol disruption to the protein.