Kumala Dewi

Characteristics of Metals Supported-Zeolites Catalysts on Steam Reforming of Bioethanol

Graphene has shown great potential for high speed devise and transparent electrode in recent years. Thermal CVD (Chemical vapor deposition) with methane gas is the most popular method for graphene synthesis. However, a high temperature of 900 C and higher is necessary for synthesizing high-quality graphene. In this study, monolayer graphene with fewer defects was synthesized using acetylene gas at 800 C. In addition, an optimal CVD condition for monolayer graphene with fewer defects was investigated by changing the nickel catalyst film thickness, hydrogen concentration, and cooling condition. The results showed that the number of the graphene layers decreased with an increase of the nickel film thickness. Furthermore, although a small amount of hydrogen reduced the amount of the defect, a lot of hydrogen etched the graphene. The fastest cooling rate in pure nitrogen was effective for synthesis of graphene with high crystallinity and with almost no defect. We succeeded in the monolayer graphene synthesis with a low density of defects on nickel catalyst film by a thermal CVD at 800 C using acetylene gas.

Flavonoid Production, Growth and Differentiation of Stelechocarpus burahol (Bl.) Hook. F. and Th. Cell Suspension Culture

BACKGROUND AND OBJECTIVE Stelechocarpus burahol is a plant containing flavonoid compounds that have the potential for use as an antihyperuricemic for gout medication. This study was performed to assess flavonoid production, growth and cell differentiation of S. burahol in cell suspension culture. METHODOLOGY Mesocarp was planted in Murashige and Skoog (MS) medium supplemented with 7.5 mg L-1 picloram for the induction of callus. Non-embryonic callus obtained was used in the formation of cell suspension cultures. Growth of cells was determined by fresh and dry weights. During the culturing, the fresh weight, dry weight and flavonoid content were determined as a result of culture status. RESULTS The growth of the S. burahol cell suspension was slow, the stationary phase occurred at 30 days. The production of flavonoids was not in line with the growth of cells and the maximum production occurred on the 15th day of the log phase. The globular-shaped cells dominated the cell suspension culture at all ages. Fluorescein diacetate (FDA) staining of cells derived from cell cultures aged for 36 days showed that some cells were still viable. CONCLUSION The results show that flavonoid production, growth and cell differentiation of a S. burahol cell suspension culture differed according to the culture age.

Intergenus Protoplast Fusion between Pichia manshurica and Rhodosporidium paludigenum to Increase the Production of Inulinase

The purpose s of this study was to identify the optimum concentration of the lytic enzyme Glucanex for protoplast isolation and to conduct fusion for the purpose of increasing inulinase production . The study performs the protoplast fusion technique using Pichia manshurica and Rh odosporidium paludigenum . Protoplast fusion consists of a series of stages: protoplast isolation , protoplast fusion , protoplast regeneration , and analysis of hybrid fusion results . Protoplast isolation and fusion success rate are determined by various factors, including age of the culture , media type, and type of lytic enzymes used . H ybrid results were analyzed using a fungicide as a marker and measuring specific growth rate ( μ) of the hybrid compared with parental growth rates. Results demonstrated that a concentration of 4 mg/ mL of Glucanex produces the greatest number of protoplasts, 7.2 x 10 10 ( c ell/mL) for P. manshurica and 8.8 x 10 10 ( c ell/mL) for Rh . paludigenum . The results of analysis of hybrid fusions indicate that the study has identified a new fusant , called fusant F4 . Fusant F4 is capable of producing the highest inulinase, 0.6892 IU, compared with parentals P. manshurica, 0557 IU, and Rh . paludigenum, 0.3263 IU. Fusant F4 has specific growth rate ( μ) of 0.3360/h and generation time ( g) of 2.0629 h .