LAPORAN HIBAH PENELITIAN STRATEGIS NASIONAL TAHUN ANGGARAN 2010

PENGEMBANGAN TEKNOLOGI BARU PRODUKSI BIOETANOL DARI NIRA SIWALAN

(Borassus flabellifer) MENGGUNAKAN FLOCCULENT Saccharomyces cerevisiae

Agustin Krisna Wardani, STP, MSi, PhD Ir. Aji Sutrisno , MSi, PhD

Dr. Ir. Bambang Susilo, M.Agr. Dibiayai Oleh Direktorat Jenderal Pendidikan Tinggi, Kementerian Pendidikan Nasional

sesuai dengan Surat Perjanjian Penugasan Dalam Rangka Pelaksanaan Hibah Penelitian Strategis Nasional Tahun Anggaran 2010 Nomor :

522/SP2H/PP/DP2M/VII/2010, tanggal 24 Juli 2010

UNIVERSITAS BRAWIJAYA NOVEMBER 2010

RINGKASAN

Untuk mencapai proses produksi etanol yang ekonomis pada proses hulu

(upstream processing) maka bahan baku nira siwalan digunakan sebagai medium

fermentasi. Selanjutnya penggunaan strain flocculent S. cerevisiae sebagai penghasil

etanol ditujukan guna mereduksi biaya produksi pada proses hilir (downstream

processing) karena strain ini memiliki kemampuan berflokulasi setelah proses

fermentasi. Sehingga tahap pemisahan etanol dari media fermentasi yang

membutuhkan biaya tinggi tidak diperlukan lagi.

Optimasi fermentasi pada penelitian ini dilakukan untuk meningkatkan

produktifitas produksi etanol, yaitu dengan penambahan berbagai konsentrasi inokulum

dan konsentrasi urea sebagai sumber N. Selanjutnya Response surface methodology

(RSM) dengan Central Composite Design (CCD) digunakan untuk mempelajari

pengaruh kombinasi komponen (konsentrasi inokulum dan urea) terhadap produktifitas

etanol.

Hasil kajian menggunakan metode RSM (Response Surface Methodology)

menunjukkan bahwa kondisi optimum dalam menghasilkan etanol tertinggi dicapai pada

kondisi konsentrasi inokulum sebesar 16,41% dan konsentrasi urea sebagai sumber

nitrogen sebesar 0.31%. Kadar etanol yang dihasilkan dari titik optimum ini adalah

sebesar 7,826%. Hasil verifikasi prediksi model menunjukkan konsentrasi etanol

sebesar 7,705%. Sedangkan yield etanol yang dihasilkan pada proses optimasi ini

adalah sebesar 0,42 dengan efisiensi sebesar 82%

SUMMARY

Response surface methodology (RSM) was employed to study the effects of two

parameters (inoculum concentration and urea concentration) on the production of

ethanol from siwalan juice in flask cultures by flocculating Saccharomyces cerevisiae

strain.

An experiment was designed by setting two parameters at three levels: X1 =

inoculum concentration (10, 15, 20%); X2 = urea concentration (0.2, 0.3, 0.4%). A

central composite design (CCD) was chosen to explain the combined effects of two

parameters and to design the minimum number of experiments. The statistical analysis

of the results showed, in the range studied, the inoculum and urea concentration had an

effects on the ethanol production. The model predicted that maximum ethanol

production was achieved at inoculum concentration of 16,41% and 0,31% of urea.

Maximum ethanol production of 7,826% was achieved under the optimized condition.

This values was in good agreement with experimental values, thus confirming the

reliability of our empirical model in optimizing ethanol production by flocculating

Saccharomyces cerevisiae. Yield and efficiency of ethanol production was 0,42 and

82%, respectively.

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