Pertumbuhan Mikroalga Chlamydomonas dalam Medium Beneck dan Air Tanah yang Mengandung Insektisida Berbahan Aktif Klorpirifos

The research of insecticide effect to the growth of genus Chlamydomonas had been done.  Research was experimental study with block random design to 9 concentrations of chlorpiriphos containing insecticide in Beneck and soil water media i.e. 0 (control), 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, and 0.40%.  Observations were done for 35 days.  Friedman test showed that there were some effects of media and insecticide concentrations on cell numbers of Chlamydomonas (cell/ml) in culture (p>0.05).  Dunnets test showed that mean of cell numbers of Chlamydomonas (cell/ml) differ (on p>0.05) and very differ (on p>0.01) on every concentrations in Beneck and soil water media.  Insecticide could reduced the cell size of Chlamydomonas, yet increased the number of cells on 0.05--0.30% concentrations in Beneck medium, and 0.05--0.20% concentrations in soil water medium.  On peak culture, insecticide with 0.10% concentration produced the highest cell numbers i.e. 21,179,167 cell/ml in Beneck medium, and 4,087,500 cell/ml in soil water medium

STUDI KARAKTERISTIK FLUORESENSI CHLORELLA spp : PENGARUH pH TERHADAP PENGKULTURAN

The Study on Fluorescence Characteristics of Chlorella spp: pH Influence on Culture. Experiments for measuringthe fluorescence characteristics of Chlorella spp. by using high stability and high repetition rate nitrogen laser ofenergy 5 mJ with pulse duration of 5 ns have been carried out. The results show that for a cell concentration rangefrom 2,625 cells/ml up to 2,769,000 cells/ml, the fluorescence intensities at pada λ = 687 nm have a linear relationshipwith the cell concentration. It has been also found that for a 7 days old chlorella culture, the pH variation at thestarting culture influenced the cell concentration.Keywords: Chlorella spp., culture, fluorescence, pH, high stability nitrogen lase

Synthesis and Characterization of Zinc Oxide Nanoparticles-based Dental Cement

Dental cement-based mixture of zinc oxide and eugenol is one of the commonly used dental cement. One of the major shortcomings that limit its application is dental cement zinc oxide and eugenol has detrimental mechanical properties. This study aims to carry out the synthesis and characterization of nano-based dental cement of zinc oxide mixed with eugenol with the hypothesis that zinc oxide nanoparticles will provide better mechanical properties. Physical and mechanical properties of cement-based dental cement oxide nanoparticles will be compared with dental cement zinc oxide microparticles.Mixing eugenol and ZnO nanoparticles were made by the composition of the powder 0.4 g, 0.45 g, 0.5 g, 0.55 g, 0.6 g and 0.2 mL of fluid. ZnO nanoparticles as a powder slowly mixed with liquid, so as to produce pasta. Methods of analysis include compressive strength, hardness and microstructure observation. From a series of studies and analysis, the surface morphology of the samples obtained by the nanoparticles-based dental cement is smoother and has a little fracture compared with microparticles-based dental cement. Likewise, the mechanical analysis of dental cement, ZnO nanoparticles can increase the compressive strength and hardness of thematerial. The conclusions are that the addition of nanoparticles can enhance physical and mechanical characteristics

Application of yeasts isolated from fermented cocoa beans for biocontrol of pathogenic mold in chocolate fruit

Contamination by pathogenic mold in postharvest cocoa beans becomes a significant concern by most Indonesian farmers. Pathogenic mold can cause damage to cocoa beans by such as rotting diseases in fruit. One alternative that can be used to control pathogenic mold is using biological agents such as yeasts. Some group of yeasts can produce cellulase enzyme that can degrade cellulose, and it can possibly break the cell wall with of mold which composed of semi-crystalline chitin, p-need, and cellulose. This study aims to determine the yeast originated from fermented cocoa beans which can produce cellulase enzymes and their potential ability as a biocontrol for pathogenic molds in chocolate fruit. This study includes yeast isolation from fermented beans, screening of yeast isolates that produce cellulase enzymes, and in-vitro antagonistic testing against pathogenic molds on chocolate fruit. The results showed that there were 21 yeast isolates from fermented cocoa beans, and among all, there were five isolates which can produce cellulase enzymes, namely isolate C4.-3.3, C4.-3.13, C4.-4.9, C4.-4.10, and C4.-5.9. Yeast isolate C4.-4.10 can produce cellulase enzymes with an index of 0.32 U/mL. This research showed that the 5 yeast isolates have the low category of cellulase enzyme, and further study is needed to be done to confirm their ability to act as a biocontrol agent

Lipid production from tapioca wastewater by culture of Scenedesmus sp. with simultaneous BOD, COD and nitrogen removal

The use of microalgae to produce biodiesel or possibly remove nutrients from industrial wastewater has gained important attention during recent years due to their photosynthetic rate and its versatile nature to grow in various wastewater systems. In this study, a microalgae, Scenedesmus sp., was cultured to enhance the lipid production and nutrients removal from tapioca wastewater sample. To assess lipid production, Scenedesmus sp. was cultured in different concentration of tapioca wastewater sample (from 0 to 100 %), and nutrient removal including BOD, COD, NH4, NO2, NO3 level by Scenedesmus sp. was assessed in 100% of tapioca wastewater culture. After 8 days of culture, it was found out that 50% of tapioca wastewater sample resulted in highest concentration of lipid content than that of the other concentrations. The level of environment indicator as nutrient removal such as BOD, COD, NH4, NO2, NO3 were also decreased up to 74%, 72%, 95%, 91%, and 91%, respectively. The pH condition changed from initial condition acidic (pH: 4) to neutral or basic condition (pH: 7-8) as recommended in wastewater treatment system. This research provided a novel approach and achieved efficient simultaneous lipid production and nutrients removal from tapioca wastewater sample by Scenedesmus's culture system