Heterologous production of enzymes degrading bioplastic by non-conventional yeast Yarrowia lipolytica

Bioplastika se pojavila kao zamjena za konvencionalnu plastiku, a alifatski poliesteri predstavljaju najbitniju skupinu biorazgradivih polimera. Na razgradnju bioplastike utječu i okolišni uvjeti i svojstva samog materijala, a enzimska hidroliza predstavlja obećavajući izbor za poboljšanje stope razgradnje. U ovom radu konstruirani su sojevi kvasca Yarrowia lipolytica koji eksprimiraju enzime koji bi mogli razgrađivati bioplastiku. Konstruirani sojevi eksprimiraju gene za: Fs kutinazu (iz Fusarium solani) i Tr kutinazu (iz Trichoderma resei), PETazu i modificiranu PETazu R280 (iz Ideonella sakaiensis) te nativnu lipazu 2. Sposobnost biorazgradnje analizirana je na krutim hranjivim podlogama koje su sadržavale alifatske poliestere, polikaprolakton (PCL) ili poli(butilen-sukcinat)-ko-(butilenadipat) (PBSA), a konstruirani sojevi mogu koristiti PCL kao jedini izvor ugljika. Na podlogama s PCLom Fs kutinaza i lipaza 2 imale su veću aktivnost na 25°C, a Tr kutinaza na 37°C. Na podlogama s PBSA-om, jedino je Tr kutinaza imala enzimsku aktivnost.Bioplastic has emerged as a substitute for conventional plastic and aliphatic polyesters are the most important group of biodegradable polymers. Bioplastic degradation depends on both environmental conditions and material properties and enzymatic hydrolysis is a promising option to improve the degradation rate. In this thesis, Yarrowia lipolytica strains, expressing selected bioplasticdegrading enzymes, were constructed. Constructed strains expressed: Fs cutinase (from Fusarium solani) and Tr cutinase (from Trichoderma resei), PETase and engineered PETaseR280 (from Ideonella sakaiensis) and native lipase 2. The biodegradation capability was analyzed by performing plate assays on two different aliphatic polyesters, poly(ε-caprolactone) (PCL) and poly(butylene succinate)-co- (butylene adipate) (PBSA) and constructed strains were able to utilize PCL as a sole carbon source. On PCL plates Fs cutinase and lipase 2 had higher activity at 25°C while Tr cutinase displayed higher activity at 37°C. However, only Tr cutinase had enzymatic activity on PBSA plates