A Novel Lipase from Rice (Oryza sativa) Bran : Purification, Identification and Characterization

Rice (Oryza sativa) bran is a by-product of rice processing, which contains rich nutrients and is a resource that can be fully utilized. However, lipase in rice bran can lead to rancidity of rice bran oil. Therefore, it is important to study the characteristics of rice bran lipase for the stable storage of rice bran. A new lipase from rice bran was isolated by DEAE Sepharose column and gel filtration column, respectively. The determination of lipase’s molecular weight and purity was conducted utilizing the SDS-PAGE technique, and the enzyme was identified through LC-MS/MS. Concurrently, an investigation was conducted on the characteristics of the lipase. The findings indicated that the lipase had a molecular weight of 36.352 kDa. Optimal catalytic activity for rice bran lipase (RBL) was observed at a temperature of 40 ℃ and pH value of 7.0, while it exhibited remarkable stability below 20 ℃ and within the pH range from 6.0 to 8.0. The stability of the RBL against various metal ions and high NaCl concentrations was observed to be relatively modest. Notably, the catalytic activity was significantly influenced by certain organic solvents (such as acetone, THF, and trichloromethane) as well as several inhibitors (P < 0.05). Furthermore, RBL demonstrated a preference for hydrolyzing long-chain p-NP esters (C12-C16).