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Lipases can be used for a variety of biotechnological applications: synthesis of fine chemicals, therapeutics, agrochemicals, cosmetics, flavors, biopolymers and biodiesel. Biodiesel is an alternative fuel for diesel engines that is environmentally acceptable. Conventionally, biodiesel is produced by transesterification of triglycerides and short chain alcohols in the presence of an acid or an alkaline catalyst. There are several problems associated with this kind of production that can be resolved by using lipase as the biocatalyst. The usage of lipases has several advantages over the conventional chemical methods. It is considered as less energy intensive and environmentally friendly. However, there are two main obstacles associated with the effective utilization of lipases in the production of biodiesel. The main one is the cost of the enzyme and its poor stability in the presence of excess alcohol. Several strategies are proposed to overcome these drawbacks: immobilization of lipases, stepwise addition of alcohol, and the usage of novel acyl acceptors and the usage of whole cell biocatalysts., Lipaze predstavljaju jednu od najvažnijih grupa biokatalizatora koji imaju veliku primenu u biotehnološkim procesima. Zahvaljujući činjenici da mogu katalizovati i hidrolizu i esterifikovanje, često se koriste u reakcijama transesterifikacije. Zbog niza prednosti koje imaju nad klasičnim katalizatorima lipaze postaju sve pogodnije za upotrebu u sintezi biodizela. U ovom radu prikazane su karakteristike lipaza koje se koriste u biotehnologiji, kao i njihova primena u sintezi biodizela.

Today, homogeneous base-catalyzed methanolysis is the most frequently used method for industrial biodiesel production. High requirements for the quality of the feedstocks and the problems related to the huge amount of wastewaters have led to the development of novel biodiesel production technologies. Among them, the most important is heterogeneous base-catalyzed methanolysis, which has been intensively investigated over the last decade in order to develop new catalytic systems, optimize the reaction conditions and to recycle catalysts. These studies are a basis for continuous development of biodiesel production on an industrial scale in the near future. The presented work summarize up-to-date studies on biodiesel production by heterogeneous base-catalyzed methanolysis. The main goals were to point out the application of different base compounds as catalysts, the methods of catalyst preparation, impregnation on carriers and recycling as well as the possibilities to improve existing base-catalyzed biodiesel production processes and to develop novel ones., Homogena bazno katalizovana metanoliza je najčešće primenjivan postupak dobijanja biodizela u industrijskim uslovima. Visoki zahtevi u pogledu kvaliteta uljnih sirovina i ekološki problemi otpadnih voda doprineli su razvoju novih postupaka sinteze biodizela. Među njima značajno mesto zauzima heterogena bazno katalizovana metanoliza ulja, koja je u poslednjoj deceniji intenzivno proučavana sa aspekta razvoja novih katalitičkih sistema, optimizacije reakcionih uslova metanolize i mogućnosti reciklovanja katalizatora. Ispitivanja ovakvih sistema čine osnovu za razvoj kontinualnih postupaka heterogene bazno katalizovane metanolize, na kojima će se u bliskoj budućnosti bazirati industrijska proizvodnja biodizela. U ovom radu analizirana su dosadašnja ispitivanja postupaka dobijanja biodizela heterogenom bazno katalizovanom metanolizom. Cilj rada je da se ukaže na primenu različitih baznih jedinjenja kao katalizatora, načine njihove pripreme, nanošenja na nosače i recikliranja, kao i na mogućnosti unapređenja postojećih i razvoja novih procesa dobijanja biodizela baznom katalizom.

Biodiesel is defined as a fuel which may be used as pure biofuel or at high concentration in mineral oil derivatives, in accordance with specific quality standards for transport applications. The main raw material used for biodiesel production is rapeseed, which contains mono-unsaturated acids (about 60%) and also poly-unsaturated fatty acids (C 18:1 and C 18:3) in a lower quantity, as well as some undesired saturated fatty acids (palmitic and stearic acids). Other raw materials have also been used in research and the industrial production of biodiesel (palm oil, sunflower oil, soybean oil, waste plant oil, animal fats, etc). The historical background of biodiesel production, installed industrial capacities, as well as the Directive of the European Parliament and of the Council (May 2003) regarding the promotion of the use of biofuels or other renewable fuels for transport are discussed in the first part of this article. The second part focuses on some new concepts for the future development of technology for biodiesel production, based on the application of non-catalytic transesterification under supercritical conditions or the use of lipases as an alternative catalyst for this reaction., Biodizel je definisan kao gorivo koje se može kao čisto ili u mešavini sa dizelom mineralnog porekla koristiti za pokretanje dizel motora. Prefiks bio ukazuje da se dobija od sirovina biljnog porekla (repičino, suncokretovo, sojino, kukuruzno, pamučno, bademovo, palmino, laneno, kokosovo, ulje od kikirikija, kao i svih vrsta masti biljnog porekla) ali se može govoriti i o bio-dizelu (ili ani-dizelu) ako se kao polazna sirovina za proizvodnju mono-alkil estara masnih kiselina koriste masnoće (trigliceridi) životinjskog porekla. Za proizvodnju estara masnih kiselina, kao biološkog goriva, najprihvatljivije je repičino ulje. U prvom delu ovog rada se izlaže istorijski pregled početka proizvodnje biodizela u Svetu, analiziraju instalirani kapaciteti u Evropi za proizvodnju biodizela, njihovo iskorišćenje, zatim se u kratkim crtama predstavlja direktiva Evropske zajednice u pogledu supstitucije dizela mineralnog porekla dobijenog iz nafte sa bio-dizelom do 2010 godine koja je usvojena prošle godine, te na kraju daje pregled standarda koje su do sada usvojile neke države koji su najveći proizvođači biodizela. U drugom članku ove serije biće prikazan razvoj nekih novih tehnologija za proizvodnju biodizela koje se zasnivaju na direktnoj nekatalitičkoj konverziji triglicerida u odgovarajuće estre masnih kiselina u natkritčnim uslovima ili korišćenje lipaza kao katalizatora.

Biodiesel is defined as a fuel that might be used as a pure biofuel or at high concentration in mineral oil derivatives, in accordance with specific quality standards for transport applications. The main raw material used for biodiesel production is rapeseed, which contains mono-unsaturated (about 60%) and also, in a lower quantity, poly-unsaturated fatty acids (C 18:1 and C 18:3), as well as some amounts of undesired saturated fatty acids (palmitic and stearic acids). Other raw materials have also been used in the research and industrial production of biodiesel (palm-oil, sunflower-oil, soybean-oil, waste plant oil, animal fats, etc). The historical background of the biodiesel production, installed industrial capacities, as well as Directives of the European Parliament and of the Council (May 2003) regarding the promotion of the use of biofuels or other renewable fuels for transport are discussed in the first part of this article (Chem. Ind. 58 (2004)). The second part focused on some new concepts and the future development of technology for biodiesel production based on the use of non-catalytic transesterification under supercritical conditions. A literature review, as well as original results based on the transesterification of animal fats, plant oil and used plant oil were discussed. Obtained results were compared with the traditional concept of transesterification based on base or acid catalysis. Experimental investigations of transesterification with supercritical methanol were performed in a 2 dm3 autoclave at 140 bar pressure and at 300°C with molar ratio of methanol to triglycerides of about 41. The degree of esterification strongly depends on the density of supercritical methanol and on the possibility of reaction occurring in one phase., U prvom članku serije na temu biodizela analizirana je proizvodnja biodizela u proteklih 20 godina, ukupno instalirani kapaciteti za proizvodnju biodizela u Evropi, trenutno iskorišćenje postojećih kapaciteta, usvojena direktiva Evropske zajednice u 2003. o supstituciji dizela mineralnog porekla dobijenog iz nafte sa biodizelom koja treba da bude primenjena do 2010. U prvom članku su navedeni standardi koji su usvojeni u nekim državama trenutno najvećim proizvođačima biodizela [1]. U drugom članku ove serije posvećene problematici biodizela analizira se nov postupak dobijanja biodizela primenom direktne konverzije trigiicerida u odgovarajuće estre masnih kiselina korišćenjem metanola u natkritčnim uslovima. U radu se, između ostalog, prikazuju originalni rezultati natkriticne transesterifikacije trigiicerida sa metanoiom izvdeni sa trigiiceridima životinjskog porekla (svinjska mast), uljem suncokreta i korišćenog biljnog ulja kao polazne sirovine za proizvodnju biogoriva odnosno biodizela.