Digital Library: No conditions. Results ordered -Date Deposited. 2024-03-29T10:11:36ZEPrintshttp://digilib.unila.ac.id/images/sitelogo.pnghttp://digilib.unila.ac.id/2016-12-21T07:34:20Z2016-12-21T07:34:20Zhttp://digilib.unila.ac.id/id/eprint/24719This item is in the repository with the URL: http://digilib.unila.ac.id/id/eprint/247192016-12-21T07:34:20ZPENGARUH PENAMBAHAN SORBITOL TERHADAP STABILITAS
ENZIM α-AMILASE DARI Bacillus subtilis ITBCCB148ABSTRAK
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.
1117011005 APRILIA ISMA DENILA apriliaisma8@gmail.com