Hydrophobic Support: A Phenomenon of Interface Lipase Activation in Polyurethane Foam as a Heterogeneous Biocatalyst in Synthesis of Natural Flavor Ester
Authors: Moentamaria Dwina , Irfin Zakijah , Chumaidi Achmad , Kusuma Heri Septya 
Published: April 2022

Biokatalis heterogen memerlukan penyangga yang sesuai melalui teknik imobilisasi enzim, terutama jika digunakan dalam industri makanan. Dalam sintesis perisa ester alami, busa poliuretan (PUF) dipilih sebagai penyangga imobilisasi lipase, karena memiliki sifat kaku inert, dan porositas tinggi. PUF perlu dilapisi dengan co-immobilized, yang terdiri dari campuran surfaktan yang aman yaitu gelatin, lecithin, PEG, MgCl2, sehingga menjadi satu kesatuan sebagai penyangga PUF hidrofobik. Interaksi hidrofobik antara lipase dan surfaktan pada PUF dapat memicu lipase yang mengaktifkan antarmuka untuk bereaksi lebih banyak dengan substrat melalui sisi aktifnya. Penelitian ini bertujuan untuk mempelajari kemampuan penyerapan PUF pada co-immobilized lipase sebagai biokatalis heterogen. Tahapan yang dilakukan adalah PUF direndam dalam co-immobilized dengan perbandingan 1:10; 1:20; 1:30 (b/b) selama 1-5 jam, kemudian dikeringkan, hasilnya direndam dalam lipase dan dikeringkan, menghasilkan biokatalis heterogen, hasil terbaik biokatalis heterogen diuji pada sintesis perisa ester alami. Hasil penelitian menunjukkan bahwa kondisi penyerapan surfaktan terbaik diperoleh selama 3 jam perendaman pada semua perbandingan PUF: co immobilized 1:10; 1:20; 1:30 (b/b) masing - masing 6,95 g/g; 23,54 g/g; 19,95 g/g, dan aktivitasnya berturut turut 2 U/g PUF; 5,86 U/g PUF; 3,34 U/g PUF. Hasil biokatalis heterogen terbaik pada rasio PUF: co immobilized 1:20 (b/b) diuji pada sintesis perisa alami melalui reaksi esterifikasi asam laurat dari minyak kelapa dan sitronelol dari minyak sereh, menghasilkan konversi 55% perisa alami citronellyl laurat.
Heterogeneous biocatalysts prepared through the enzyme immobilization technique require an appropriate carrier, especially if they are used in the food industry. In the synthesis of natural ester flavor, polyurethane foam (PUF) was chosen as the lipase immobilization carrier, because it has rigid properties, inert, and high porosity. Carrier PUF needs to be coated with a food-safe surfactant known as co-immobilized, consisting of a mixture of gelatin, lecithin, PEG, and MgCl2, so that it becomes a single unit as support for hydrophobic PUF. The interaction hydrophobic between lipases and surfactants in PUF can trigger interface-activating lipases to react more with substrates through their active sites. This study aims to study the sorption capability of PUF on co-immobilized lipase as a heterogeneous biocatalyst. The steps taken were PUF was immersed in co-immobilized in a ratio of 1:10; 1:20; 1:30 (w/w) for 1-5 h, then dried, the results were soaked in lipase and dried, producing heterogeneous biocatalysts, the best results of heterogeneous biocatalysts were tested by natural flavor ester synthesis. The results showed that the best sorption conditions were obtained for 3 hours of immersion in all PUF: immobilized co ratio 1:10; 1:20; 1:30 (w/w) was 6.95 g/g; 23.54 g/g; 19.95 g/g, and each activity was 2 U/gram PUF; 5.86 U/gram PUF; 3.34 U/gram PUF. The best result of heterogeneous biocatalyst at the ratio of PUF: co immobilized 1:20 (w/w) was tested on the synthesis of natural flavors through the esterification reaction of lauric acid from coconut oil and citronellol from citronella oil, resulting in a conversion of 55% to citronellyl laurate natural flavor.