The production of lipase from Thermomyces lanuginosus with the aim to develop a sustainable enzyme-catalysed biodiesel process

Enzimski kataliziranom transesterifikacijom biljnih ulja uz prisustvo alkohola (metanola) proizvodi se biodizel visoke čistode pri blažim procesnim uvjetima (pH, temperatura), za razliku od kemijski katalizirane transesterifikacije koja je energetski zahtjevnija jer se odvija na višim temperatura uz mogudnost nastajanje neželjnih produkata koje je potrebno ukloniti. U ovome radu istraživan je proces proizvodnje enzima lipaza tijekom uzgoja gljive Thermomyces lanuginosus u uvjetima fermentacije na čvrstim nosačima na trima različitim supstratima, pogači buče, konoplje i lana, s ciljem daljnje primjene lipaze u sintezi biodizela iz suncokretovog ulja i metanola. Svakodnevno su mjerene volumna i specifična aktivnost lipaze tijekom 9 dana fermentacije. Najveda volumna i specifična aktivnost lipaze postignuta je u pokusu u kojem je korištena pogača konoplje kao supstrat (V.A. = 41,3 U cm\(^{-3}\), S.A. = 68,2 U mg\(^{-1}\). Postupkom isoljavanja s amonijevim sulfatom, volumna i specifična aktivnost enzima lipaza povedana je za deset puta. Udio metilnih estera nastalih transesterifikacijom u konačnom produktu primjenom komercijalnog enzima lipaza kao katalizatora iznosila je 95,2 %, a primjenom vlastito proizvedenog nepročišdenog enzima lipaza 11,5 %.In an enzyme-catalysed transesterification of plant oils in the presence of alcohol (methanol), biodiesel of high purity under mild conditions of pH and temperature can be produced, in comparison with chemically catalysed transesterification. In the chemically catalysed transesterification, the process conditions are more extreme because of the higher temperature with possibilities of development undesired products which have to be separated. In this work, the production of a lipase from Thermomyces lanuginosus was investigated under solid state conditions using three different substrates, cakes obtained after production of pumpkin, hemp and flax oils, with the aim to apply the produced lipase in the production of biodiesel from sunflower oil and methanol. Volume and specific activities of the enzyme were measured daily during nine days of fermentation. The highest volume and specific activities were obtained in the experiment when hemp oil cake was used as a substrate (V.A. = 41.3 U cm\(^{-3}\), S.A. = 68.2 U mg\(^{-1}\). Ten folds higher lipase activites were reached after the subsequent salting-out process with ammonium sulphate. The amount of methyl esters in the final product obtained by application of commercial lipase as catalyst was 95.2%, while in the experiment performed with crude enzyme it was 11.4%