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Rochmadi -
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Biochemistry, Genetics & Molecular Biology Immunology & microbiology Materials Science & Nanotechnology

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Effects of Dissolved Oxygen Tension and Ammonium Concentration on Polyhydroxybutyrate Synthesis from Cassava Starch by Bacillus cereus IFO 13690 ., Margono; ., Rochmadi; Syamsiah, Siti; Cahyanto, Muhammad Nur
Indonesian Journal of Biotechnology Vol 14, No 1 (2009)
Publisher : Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (492.915 KB)

Abstract

Attempting to get low price of raw material for producing polyhydroxybutyrate is always studied. Tapioca starch is one of the raw material with low price. The objective of this research was to study the effects of initial ammonium concentration and dissolved oxygen tension (doT) on producing PHB by Bacillus cereus IFO 13690 with tapioca starch as the carbon source. This fermentation was carried out in 5 L fementors with a 2 L working volume, temperature of 30 oC, and agitation of 500 rpm. The pH medium was controlled at 5.6 after it came down from the initial pH of 6.8. Meanwhile, the initial doT was 100 % air saturation and also came down to and maintained at doT of experiment, i.e. 1 , 5 , or 10 % air saturation. The best result was obtained when the initial ammonium concentration was 5 g/L and the doT value maintained at 5 % air saturation. By this conditions, the cell growth reached 5,457 g cell dry weight/L containing PHB of 2.42 % cell dry weigh after 29 hours fermentation.
LAJU PELEPASAN DIAZINON DARI MIKROKAPSUL BERBASIS MELAMIN FORMALDEHID Suhartaya, Noviana Utami Ciptaningtyas; Mulyono, Panut; -, Rochmadi
Jurnal Bahan Alam Terbarukan Vol 2, No 1 (2013): June 2013
Publisher : Semarang State University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jbat.v2i1.2910

Abstract

The microcapsules containing diazinon as the core material and melamine formaldehyde as the membrane material have been synthesized by in situ polimerization method. The microcapsule membrane on this researches was modified in two types, the first, melamine formaldehyde (MF) and the second types, melamine formaldehyde added with sodium dodecyl sulphate and polyvinyl alcohol (MF-SDSPVA). This research aims to study the effect of pH and temperature on the release rate of diazinon in aqueous medium. The results showed that the pH and temperature has little effect on the release rate of diazinon from microcapsule based on melamine formaldehyde. This is due to the diffusion through the microcapsule membrane is not influenced by the pH and temperature of the solution outside of microcapsule.
Co-Authors Margono . Muhammad Nur Cahyanto Noviana Utami Ciptaningtyas Suhartaya Panut Mulyono Siti Syamsiah