(485as) Enzymatic Synthesis of Isoniazid Catalyzed by Lipase Immobilized Into Chitosan and Green Coconut Fiber

The specificity of enzymes and their ability to catalyze reactions make them attractive for applications in biochemical and industrial fields. One major advantage of this biocatalyst specificity is the achievement of targets free of side products. Immobilization offers some operational advantages over free enzymes, such as choice of batch or continuous processes, rapid termination of reactions, controlled product formation, ease of removal from the reaction mixture and adaptability to various engineering designs. By careful selection of the matrix, it is also possible to vary the nature of the immobilized derivative in order to improve enzyme activity and stability and also to allow easier handling and storage. Isonicotinic acid hydrazide known as isoniazid, in particular, has been found to be tuberculostatic. A major advance in the treatment of tuberculosis was signaled by the introduction into therapy of the antibiotic rifampicin. The chemical process to synthesize isoniazid uses 4-cyanopyridine and hydrazine hydrate as reactants in the presence of sodium hydroxide at 100 ¨¬C under reflux conditions. It is a hazardous and expensive process. By contrast, the lipase catalyzed reaction can be conducted at milder temperature and is intrinsically attractive. Lipases are widely used for the solution of many synthetic organic problems. These enzymes catalyze both the hydrolysis of esters in largely aqueous media and their synthesis under low water conditions. Due to economical considerations, their application on an industrial scale requires their immobilization and re-usability. Thus, the objective of this work is the enzymatic synthesis of isoniazid catalyzed by different lipases (Candida Antarctica and Yarrowia lipolytica) immobilized into chitosan or green coconut fiber analyzing some reaction parameters such as effect of catalyst, temperature, initial concentration of substrates (hydrazine and ethyl isonicotinate). The derivatives will be prepared according to existent literature and the synthesis will be carried out in a batch reactor using 1,4-dioxane as solvent. Concentrations of substrates and products are determined using HPLC, Merck 50938 column with a stationary phase of Lichrosphere 100 RP-18, particle size 5 mm, prepacked on a 250mm • 4mm i.d. Mobile phase composed of methanol:water (70:30). Flow rate = 0.8 ml/min at 25° and ¥ë = 273 nm. It is expected the work shows that isoniazid, a prime drug in the treatment of tuberculosis, can be synthesized by different immobilized lipases catalyzed hydrazinolysis reaction in 1,4-dioxane as a solvent achieving conversions higher than 45% and prepared derivatives present high operational stability.