Screening isolat fungsi lipolitik indigenus dan karakterisasi lipase yang dihasilkan pada solid-state fermentation

DARMASIWI, Sari, Dr. Ir. Chusnul Hidayat

2010 | Tesis | S2 Bioteknologi

Lipase berperan mengkatalisis reaksi hidrolisis asilgliserol menjadi asam lemak dan gliserol serta sintesis ester asam lemak. Aplikasi lipase sebagai katalis telah banyak digunakan dalam berbagai bidang industri, akan tetapi hal ini masih terkendala oleh harga lipase komersial yang mahal. Untuk mengatasi hal ini, dilakukan screening isolat fungi lipolitik dari sumber alam Indonesia yang diproduksi menggunakan medium limbah bungkil jarak secara solid-state fermentation. Tujuan penelitian adalah mendapatkan isolat fungi lipolitik indigenus yang bersumber dari kacang tanah dan jagung yang menghasilkan aktivitas hidrolisis dan esterifikasi tinggi, serta mengevaluasi karakteristik lipase isolat fungi terpilih yang diproduksi pada medium bungkil jarak secara solid-state fermentation. Metode penelitian terdiri atas 4 tahapan yaitu (1) screening isolat fungi secara kualitatif pada medium PDA-tributirin, (2) screening isolat terpilih terhadap aktivitas lipase secara kuantitatif pada medium bungkil jarak secara solid-state fermentation (3) karakterisasi lipase yang dihasilkan oleh isolat fungi terpilih, (4) fraksinasi lipase dengan menggunakan presipitasi amonium sulfat. Hasil penelitian menunjukkan isolat Aspergillus niger 65I6 sebagai isolat yang menghasilkan lipase dengan aktivitas hidrolisis dan esterifikasi tertinggi diantara ketujuh isolat yang diuji yaitu sebesar 63,25 U/g dan 316,25 U/g. Karakteristik lipase yang dihasilkan isolat Aspergillus niger 65I6 memiliki kondisi optimum reaksi terbaik pada pH 8, stabilitas pada pH 7; suhu optimum reaksi terbaik dan stabilitas tertinggi pada 40°C; bersifat spesifik menghidrolisis triasilgliserol rantai panjang, dan stabil pada pelarut organik polar. Fraksinasi amonium sulfat mencapai optimum pada kejenuhan 50%, namun yield yang dihasilkan rendah. Dari hasil penelitian disimpulkan isolat Aspergillus niger 65I6 menghasilkan aktivitas hidrolisis dan esterifikasi tertinggi, dengan karakteristik yang berbeda dari lipase Aspergillus lain yang telah diteliti sebelumnya. Dengan demikian, bungkil jarak merupakan media yang potensial untuk produksi lipase.

Lipase is an enzyme that catalyzes the hydrolysis reaction of acyglycerol in which free fatty acids and glycerol were released. It also acts as catalyst in the synthesis reaction of esters. Lipase applications as a catalyst in industrial sector are really extensive. However, commercial lipase is still very expensive. Alternative ways to solve this problem were screening a new source of indigenous lipolytic fungi in which the best isolate was used for producing lipase using a lowcost medium such as Jatropha cake on solid-state fermentation method. The aims of this research were to obtain an indigenous lipolytic fungus, which has high hydrolytic and esterification activity, and to evaluate the characteristic of lipase that was produced using solid-state fermentation in jatropha cake medium. The methods of this research were conducted in 4 steps: (1) qualitative screening of fungal isolates on PDA-tributyrin medium, (2) quantitative screening of selected isolates on Jatropha cake fermentation medium using solid-state fermentation method, (3) characterization of lipase that was produced by solidstate fermentation from the selected isolate, (4) fractionation of lipase using ammonium sulphate precipitation. The results of this research showed that Aspergillus niger 65I6 was a potential isolate that produced highest hydrolytic and esterifi cation activity which was about 63,25 U/g and 316,25 U/g . It has an optimal hydrolytic activity at pH 8, stable at pH 7, optimum temperature and stable was at 40°C. It had specificity to hydrolyze long chain triacylglycerols and relative stable in organic polar solvents. The fractionation using ammonium sulphate showed optimum at concentration of 50%. However, the yield was low. It was concluded that Aspergillus niger 65I6 had a high potential in producing lipase, and also had different characteristics with another Aspergillus lipase known before. Thus, it showed that the Jatropha cake was a potential source to be used as fermentation medium for lipase production.

Kata Kunci : Screening,Fungsi,Lipase,Solid state fermentation,Karakterisasi,characterization