Neem oil ( <i>Azadirachta indica</i> ) as a promising feedstock for biolubricant production: enzymatic synthesis, process optimization, and molecular studies

Abstract The fuel industry remains closely tied to oil‐based fuels. This relationship is responsible for increasing greenhouse gas emissions. Biofuels are an alternative to petroleum‐based fuels that could make industrial production lines more sustainable. Neem oil ( Azadirachta indica ) was tested as a raw material for the enzymatic synthesis of biolubricants. Eversa Transform 2.0 lipase was tested as a biocatalyst during this process. The Taguchi method was used to determine the optimal point for maximizing production. The best result was achieved with a molar ratio of 1:5 (mol mol −1 ) between free fatty acids and 2‐ethylhexan‐1‐ol, using 10% biocatalyst at 40 °C for 96 h. Theoretical conversion was 89.9%, whereas the experimental value was 89.2% ± 0.04%. A theoretical study showed that eicosanoic acid interacts with His 268 (NAC), a component in the enzyme’s active site, displaying favorable free energy and forming specific hydrogen bonds along with alkyl and π –alkyl interactions. Finally, the characterization analyses – gas chromatography–mass spectrometry (GC–MS) and Fourier transform infrared (FTIR) spectroscopy – confirm the efficient production of biolubricants from neem oil. This vegetable oil is thus a promising source of biofuels.