PENGARUH PENAMBAHAN SORBITOL TERHADAP STABILITAS ENZIM α-AMILASE DARI Bacillus subtilis ITBCCB148

APRILIA ISMA DENILA , 1117011005 (2016) PENGARUH PENAMBAHAN SORBITOL TERHADAP STABILITAS ENZIM α-AMILASE DARI Bacillus subtilis ITBCCB148. FAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAM, UNIVERSITAS LAMPUNG.

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Abstrak

ABSTRAK Enzim α-amilase merupakan enzim yang penting dalam bidang pangan, bioteknologi dan industri serta berperan dalam hidrolisis amilum dengan memutus ikatan α-1,4 glikosida. Pada bidang industri, enzim ini harus mampu bekerja pada pH ekstrim dengan stabilitas termal yang tinggi, namun pada umumnya enzim tidak stabil pada kondisi tersebut. Tujuan penelitian ini adalah untuk mempelajari pengaruh penambahan sorbitol terhadap stabilitas enzim α-amilase dari Bacillus subtilis ITBCCB148. Untuk mencapai tujuan tersebut, telah dilakukan berbagai tahap yaitu : produksi, isolasi, serta pemurnian secara fraksinasi ammonium sulfat dan dialisis. Aktivitas enzim α-amilase ditentukan dengan metode Fuwa dan Mandels sedangkan kadar protein enzim ditentukan dengan metode Lowry. Hasil penelitian menunjukan bahwa enzim hasil pemurnian memiliki aktivitas spesifik sebesar 4185,70 U/mg, meningkat 11 kali dibandingkan ekstrak kasar enzim dengan aktivitas spesifik sebesar 373,559 U/mg. Enzim hasil pemurnian ini memiliki pH optimum 6,5; suhu 60°C; nilai KM = 9 μmol/mL.menit; Vmaks = 500 μmol/mL.menit, nilai ki = 0,029 menit-1; t1/2 = 23,896 menit; ΔGi = 103,009 KJ mol-1. Uji stabilitas termal enzim setelah penambahan sorbitol 0,5 M memiliki nilai KM = 3,4 μmol/mL.menit, Vmaks = 200 μmol/mL.menit, nilai ki = 0,021 menit-1; t1/2 = 33 menit; ΔGi = 103,903 KJ mol-1, sorbitol 1,0 M memiliki nilai KM = 4,95 μmol/mL.menit, Vmaks = 333,333 μmol/mL.menit, nilai ki = 0,016 menit-1; t1/2 = 43,312 menit; ΔGi = 104,312 KJ mol-1, dan sorbitol 1,5 M memiliki nilai KM = 7,5 μmol/mL.menit, Vmaks = 500 μmol/mL.menit, nilai ki = 0,012 menit-1; t1/2 = 57,75 menit; ΔGi = 105,452 KJ mol-1. Penambahan sorbitol terhadap enzim α-amilase dari Bacillus subtilis ITBCCB148 menunjukan peningkatan stabilitas termal enzim berdasarkan peningkatan waktu paruh dan ΔGi serta turunnya nilai ki. Kata Kunci : α-amilase, Bacillus subtilis ITBCCB148, sorbitol. ABSTRACT α-amylase is an enzyme that is important in the field of food, biotechnology, and industry as well as play a role in the hydrolysis of starch, to break the α-1,4 glycoside. In a specific industry, this enzyme must be capable of working at extreme pH with high thermal stability, but in general the enzyme is not stable in these condition. The purpose of this research was to study the effects of sorbitol on the stability of the enzyme α-amylase from Bacillus subtilis ITBCCB148. To achieve these objectives, it has been carried out a number of stages, i.e: production, isolation, and purification by ammonium sulfate fractination and dialysis. The enzyme activity was determined by the method of Fuwa and Mandels while the enzyme protein content determined by the method of Lowry. The results showed that the purified enzyme has a specific activity of 4185.7 U/mg, an increased of 11 fold compared to crude extract of the enzyme with a specific activity of 373.559 U/mg. Purified enzyme has a pH optimum 6.5; temperature 60°C; KM= 9 μmol/mL.sec; Vmax= 500 μmol/mL.sec; ki = 0.029 sec-1; t1/2 = 23.896 sec; ΔGi = 103.009 KJ.mol-1. Kinetic data of the enzyme after the addition of 0.5 M sorbitol has the KM= 3.4 μmol/mL.sec; Vmax = 200 μmol/mL.sec; ki = 0.021 sec-1; t1/2 = 33 sec; ΔGi = 103.903 KJ.mol-1, addition of 1.0 M sorbitol has the KM= 4.95 μmol/mL.sec; Vmax = 333.333 μmol/mL.sec; ki = 0.016 sec-1; t1/2 = 43.312 sec; ΔGi = 104.312 KJ.mol-1; and addition of sorbitol 1.5 M has the KM= 7.5 μmol/mL.sec; Vmax = 500 μmol/mL.sec; ki = 0.012 sec-1; t1/2 = 57.75 sec; and ΔGi = 105.452 KJ.mol-1. The addition of sorbitol to the α-amylase from Bacillus subtilis ITBCCB148 showed increase the thermal stability of the enzyme which showed on an increment in half-life ΔGi and capability to decrease the ki value. Keyword : α-amylase, Bacillus subtilis ITBCCB148, sorbitol.

Tipe Karya Ilmiah: Skripsi
Subyek: Q Science (General) > QD Chemistry
Program Studi: Fakultas MIPA > Prodi Kimia
Depositing User: 5393430 . Digilib
Date Deposited: 21 Dec 2016 07:34
Last Modified: 21 Dec 2016 07:34
URI: http://digilib.unila.ac.id/id/eprint/24719

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