Biocatalytic synthesis of drugs is imperative to avoid the hazardous environmental effects of the pharmaceutical production processes. In view of this, biocatalytic synthesis of aspirin is discussed in the present work. A crude lipase extracted from Geobacillus sp. was crosslinked using N,N-methylenebisacrylamide (N,N-MBAAm) and two different initiators: ammonium persulphate (APS) and gamma-irradiation. The crude lipase was crosslinked as such bypassing the separation procedures using a biocompatible crosslinker. The crosslinked lipase was characterized by various techniques and evaluated for its activity profile as a function of time, temperature, pH and substrate concentration and results were compared to its free form. The activity profile of the crosslinked lipase was observed to be only marginally lower than the free lipase. The crosslinked lipases were used as catalysts in the green synthesis of acetylsalicylic acid, aspirin, directly from the acetic acid. The reusability studies of the crosslinked lipases were carried out up to 10 cycles. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.