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Yati Sudaryati Soeka
Bidang Mikrobiologi, Pusat Penelitian Biologi-LIPI

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AKTIVITAS ANTIMIKROBA FLAVONOID - GLIKOSIDA HASIL SINTESIS SECARA TRANSGLIKOSILASI ENZIMATIK Yati Sudaryati Soeka; Elidar Naiola; Joko Sulistyo
BERITA BIOLOGI Vol 8, No 6 (2007)
Publisher : Research Center for Biology-Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/beritabiologi.v8i6.825

Abstract

Flavonoid-glycoside was synthesized enzymatically using CGT-ase (EC.2.4.1.19) of indigenous Bacillus licheniformis in a phosphate buffer pH 6.0 at 45°C for 24 h, through transglycosylation reaction in the present of flavonoid those were extracted from rhizomes such as ginger, flngerroot, turmeric, white turmeric and white curcuma as natural acceptors, and commercial rice,cassava, corn and wheat flour as substrates.The result showed that CGT-ase of B. licheniformis transferred a glycosyl moiety in a bilayer enzymatic reaction system of n-hexanol and phosphate buffer yielding glycosides as transfer products in the present of wheat flour as substrate and white curcuma extract as its acceptor.An inhibitory effects of the synthesized flavonoid glycosides against microbial growth was furthermore examined. It was found that flavonoid-glycoside, as the transfer product, exhibited high antimicrobial activity at MIC 200 ppm on the growth of Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae, however no effect when it was assayed on Candida tropicalis, while arbutin and flavonoid-aglycon showed very low inhibitory activity on the growth of two out of four tested microbial strains.
OPTIMASI DAN KARAKTERISASI a-AMILASE DARI ISOLAT AKTINOMISETES YANG BERASAL DARI KALIMANTAN TIMUR Yati Sudaryati Soeka
BERITA BIOLOGI Vol 10, No 3 (2010)
Publisher : Research Center for Biology-Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/beritabiologi.v10i3.751

Abstract

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.