@misc{eprints33171,
           month = {Agustus},
           title = {KONVERSI ENZIMATIS PATI SAGU MENJADI GLUKOSA
MENGGUNAKAN ENZIM ?-AMILASE DARI Bacillus Subtilis
ITBCCB148 YANG DIAMOBILISASI DENGAN KITOSAN UNTUK
PRODUKSI BIOETANOL},
          author = { 1417011080 NI PUTU RAHMA AGUSTINA},
         address = {UNIVERSITAS LAMPUNG},
       publisher = {FAKULTAS MATEMATIKA DAN ILMU PENGETAHUAN ALAM },
            year = {2018},
             url = {http://digilib.unila.ac.id/33171/},
        abstract = {Kebutuhan bahan bakar saat ini semakin meningkat sementara ketersediaan
bahan bakar fosil terus berkurang. Oleh karena itu, diperlukan sumber energi
alternatif untuk mengatasi masalah tersebut. Bioetanol merupakan salah satu
sumber energi alternatif yang dapat diperbaharui dan berpeluang untuk
menggantikan sumber energi yang tidak dapat diperbaharui. Penelitian ini
bertujuan untuk memanfaatkan pati sagu sebagai bahan baku untuk memproduksi
bioetanol. Pati sagu dikonversi menggunakan enzim {\ensuremath{\alpha}}-amilase dari Bacillus
subtilis ITBCCB148 yang diamobilisasi dengan matriks kitosan melalui metode
ikatan silang menjadi glukosa. Tahap penelitian ini meliputi proses isolasi enzim,
pemurnian enzim, amobilisasi enzim, karakterisasi enzim hasil pemurnian dan
amobilisasi serta konversi enzimatis pati sagu dan fermentasi bioetanol dengan
bantuan Saccharomyces cerevisiae.
Hasil penelitian menunjukkan bahwa aktivitas spesifik enzim {\ensuremath{\alpha}}-amilase hasil
pemurnian hingga tahap dialisis adalah 4.576,43 Umg-1 dan kemurniannya
meningkat 9 kali dibandingkan dengan ekstrak kasar enzimnya. Enzim {\ensuremath{\alpha}}-amilase
hasil pemurnian memiliki suhu optimum 65oC, KM = 2,037 mgmL-1 substrat, dan
Vmaks = 28,571{\ensuremath{\mu}}molmL-1 menit-1. Enzim {\ensuremath{\alpha}}-amilase hasil amobilisasi memiliki
suhu optimum75oC, KM = 2,046 mgmL-1 substrat, dan Vmaks= 27,027 {\ensuremath{\mu}}molmL-1
menit-1. Aktivitas sisa enzim hasil pemurnian dan hasil amobilisasi dalam uji
stabilitas termal pada suhu 60oC selama 80 menit berturut-turut sebesar 21\% dan
81\%. Enzim amobil dapat digunakan berulang hingga 5 kali. Data kinetika enzim
hasil pemurnian diperoleh waktu paruh (t1/2)= 32,38 menit, ki= 0,0214 menit-1, dan
{\ensuremath{\Delta}}Gi= 177,7 kJmol-1. Data kinetika enzim hasil amobilisasi diperoleh t? = 256,67
menit, ki = 0,0027 menit-1, dan {\ensuremath{\Delta}}Gi yaitu 214,8 kJ mol-1. Berdasarkan penurunan
nilai ki , peningkatan nilai {\ensuremath{\Delta}}Gi dan t1/2, diketahui bahwa amobilisasi menggunakan
kitosan dapat meningkatkan stabilitas enzim {\ensuremath{\alpha}}-amilase dari B. subtilis
ITBCCB148. Selanjutnya, hasil fermentasi S. cerevisiae pada pati sagu yang
dikonversi dengan enzim {\ensuremath{\alpha}}-amilase didapatkan kadar etanol sebesar 0,26\% (w/v).
Kata kunci : ?-amilase, amobilisasi, B. subtilis ITBCCB148, kitosan,
S. cerevisiae

abstract

Current fossil fuel demand are increasing recently however the supply of that
fuels became decreasing. An alternative energy sources are intended to address
concerns about fossil fuels. Bioethanol is one of the alternative energy sources
that is renewable and has a chance to subtitute un-renewable energy sources such
as fossil fuels. The aims of this study were to utilization of sago starch as raw
material for bioethanol production. Sago converted using {\ensuremath{\alpha}}-amylase from
Bacillus subtilis ITBCCB148 that was immobilized through crosslinking method
on chitosan matrix into glucose. The sequential processes applied as following:
enzyme isolation, enzyme purification, enzyme immobilization, characterization
of the purified and immobilized enzyme, saccharification of sago starch and
bioethanol fermentation using Saccharomyces cerevisiae.
The results showed that the specific activity of purified {\ensuremath{\alpha}}-amylase enzyme
after the dialysis stage was 4576.43 Umg-1 and its purity 9 times higher than the
crude extract enzyme. The purified {\ensuremath{\alpha}}-amylase enzyme has an optimum
temperature of 65oC, KM = 2.037 mgmL-1 substrate, dan Vmaks = 28.571
{\ensuremath{\mu}}molmL-1 min-1. The immobilized {\ensuremath{\alpha}}-amylase enzyme has an optimum
temperature of 75oC, KM = 2.046 mgmL-1 substrate, dan Vmaks= 27.027 {\ensuremath{\mu}}molmL-1
min-1. The residual activity of the purified enzyme and immobilized enzyme in the
study of thermal stability on 60oC for 80 minutes were 21\% dan 81\% respectively.
The immobilized enzyme can be used repeadly up to 5 times. The kinetic studies
of the purified enzyme were obtained half-life (t1/2 ) was 32.38 minutes, ki was
0.0214 min-1, and {\ensuremath{\Delta}}Gi was 177.7 kJ mol-1. The investigation of the kinetic studies
of immobilized enzyme showed that t? was 256.67 minutes, ki was 0.0027 min-1,
and {\ensuremath{\Delta}}Giwas 214.8 kJmol-1. Based on the decreasing of ki value, increasing of {\ensuremath{\Delta}}Gi
and t1/2, the immobilization by chitosan in this study improved the stability of {\ensuremath{\alpha}}-
amylase from B. subtilis ITBCCB148. Futhermore, the S. cerevisiae fermentation
on sago starch converted by the immobilized {\ensuremath{\alpha}}-amylase enzyme obtained ethanol
approximately 0,26\% (w/v).
Keywords : {\ensuremath{\alpha}}-amylase, immobilization, B. subtilis ITBCCB148, chitosan,
S. cerevisiae}
}