Production of amylase by indigenous thermophilic bacteria isolates

• Published in: Penelitian Pertanian (Indonesia) Vol. 18; no. 2
• Main Authors: Richana, N, Azizah, N, Damardjati, D.S. (Balai Penelitian Bioteknologi Tanaman Pangan, Bogor (Indonesia)), Yusri, N, Murdiyatmo, U
• Format: Journal Article
• Language: English
• Published: 1999
• Subjects: ALMIDON; AMIDON; AMILASAS; AMYLASE; AMYLASES; BIOCONVERSION; ENZIMAS; ENZYME; ENZYMES; MICROORGANISME THERMOPHILE; MICROORGANISMOS TERMOFILOS; PRODUCCION; PRODUCTION; STARCH; THERMOPHILIC MICROORGANISMS
• ISSN: 0216-9959

Amylase-producing thermophilic bacteria were isolated from the soil sample taken from Dieng Vulcanic. Diluted soil sample to 10 at the power of -8 - 10 at the power of -11 was spread out on enriched culture with starch. The appearance of colony surrounded by clear zone were presumed as a result of amylase hydrolysis. Two selected isolates were obtained based on their capacity to excrete high amount of amylase, namely TII-12 and TVII-6. Specific activity of amylase produced by TII-12 and TVII-6 were 1646.21 and 1624.37 U/mg protein respectively. Production of amylase in a 21-bioreactor by these isolates were operated at optimum condition pH 6.5, temperature 50 deg. C, aeration 1.0 vvm and agitation 150 rpm. Result showed that maximum specific activity of enzyme of 2032.3 U/mg protein can be reached after 20 hours cultivation. Crude enzyme was obtained from precipitation of broth with aceton (3:2), and dissolved in phosphate-citrabuffer. Bioconvertion of starch by these enzyme could reached optimum under condition of pH 6 and temperature 90 deg. C, with enzyme and substrate ratio 20 percent incubation period 75 minutes for isolate TII-12, enzyme and substrate ratio 5 percent, incubation period 60 minutes for isolate TVII-6 Bakteri penghasil amilase telah diisolasi dari tanah asal Kawah Dieng. Contoh tanah dilakukan pengenceran bertingkat sampai 10-8-10-11, kemudian diisolasi menggunakan media yang diperkaya dengan pati. Koloni yang menampakkan zona bening di sekelilingnya diduga bakteri penghasil amilase. Dari hasil seleksi berdasarkan kemampuan menghasilkan amilase diperoleh dua isolat unggul, yaitu TII-12 dan TVII-6. Aktivitas spesifik amilase isolat TII-12 dan TVII-6 berturut-turut adalah 1646,21 dan 1624,37 U/mg protein. Kondisi optimum untuk produksi amilase oleh kedua isolat tersebut pada bioreaktor-21 adalah pada pH 6,5, suhu 50 derajat C, aerasi 1,0 vvm dan agitasi 150 rpm. Hasil penelitian menunjukkan, aktivitas spesifik enzim maksimum sebesar 2032,2 U/mg protein dicapai pada jam ke-20 kultivasi. Enzim kasar yang diperoleh dari pengendapan cairan fermentasi dengan penambahan aseton (3:2), dilarutkan pada bufer fosfat sitrat. Biokonversi pati oleh enzim mempunyai kondisi optimum pada pH 6 dan suhu 90 derajat C dengan perbandingan enzim dan substrat 20 persen, selama 75 menit untuk isolat TII-12 dan perbandingan enzim dan substrat 5 persen selama 60 menit untuk isolat TVII-6