Yati Sudaryati Soeka

OPTIMASI DAN KARAKTERISASI a-AMILASE DARI ISOLAT AKTINOMISETES YANG BERASAL DARI KALIMANTAN TIMUR [Optimization and Characterization of Amylase from Actinomycetes Isolates From East Kalimantan]

Forty-one actinomycetes isolates from East Kalimantan held in Microbiology Division Collection-UPI, and their ability to produce a-amylase has been assessed. Those 41 number of actinomycetes isolates performed amylolytic activity as shown by clear zone areal after being poured with iodium solution. The bacteria produced high a-amylase when was grown in media containing starch soluble 2% the a-amylase activity in media containing 8.24 U/ml. The isolate (number 7) was the most active compared to another (number 100) and it was identified as Nocardia; the activity of this enzyme obtained was 12.93 U/ml (one unit activity is defined as mol of glucose produced per ml per minute). The maximum temperature for enzyme reaction was 40°C, optimum pH was pH 7.5 the a-amylase activity were 15.76 U/ml and 31.11 U/ml, respectively. From kinetic characterization study, it was found that enzyme showed Km and Vmax value of 7.62 % (b/v) and 71.10- umol/ml/minute respectively at condition of temperature 40°C, pH 7.5 and incubation time 10 minute.

SEMI PURIFIKASI DAN UJI REAKSI TRANSGLUKOSILASI P-GLUKOSIDASE DARI Aspergillus pulverulentus Transglycosylation Reaction of Partially Purified Aspergillus pulverulentus P-Glucosidase

An extracellular p-glucosidase[EC 3.2.1.21]derived from Asvereillus vulverulentus were separated and partially purified by successive chromatographies and its some characterization and transglucosylation capacity were studied.The purification protocol included precipitation with ammonium sulphate,gel filtration,ion exchange chromatography and native polyacrylamide gel electrophoresis.The enzyme readily hydrolysed cellobiose to form transglucosylation products in the present of primary alcohol acceptors.This P-glucosidase was stable at temperatures up to 70 °C and from pH 2.5 to 8.5, while its highest activity was in the pH 4.5 at 65°C.