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Articles by Dea Indriani Astuti
Total Records ( 6 ) for Dea Indriani Astuti
  Noor Rahmawati , Ariesta Rakhmat Isfandito , Dea Indriani Astuti and Pingkan Aditiawati
  This study aims to isolate and identify endophytic fungi from tissues of stem wood at different age of Toona sinensis and test the antioxidant activity produced from the culture of these fungi. Twenty five isolates were obtained and identified into 7 types of fungi classes; compromising of Trichoderma sp., Aspergillus sp., Rhizopus sp., Cladosporium sp., Penicillium sp., Alternata sp. and Chepalosporium sp. The fungus were then cultured into 100 mL of PDB medium, agitated at 150 rpm, at 28°C for 1 week. Cultures containing antioxidant compound were extracted using n-hexane and ethyl acetate and the antioxidant activity was determined by DPPH method. The ethyl acetate extracts of culture filtrate has higher antioxidant activity comparing than n hexane extracts. Among the 25 isolates, the antioxidant activity of n-hexane extract of culture Penicillium sp., number 1, isolated from 5 years surian branch had the greatest DPPH radical scavenger of 27.79% and the lowest one was 22.29% obtained from Cladosporium sp. and Trichoderma sp., number 8. Whereas antioxidants compound extracted by ethyl acetate of Rhizopus sp., number 2, from 5 months stem shoot had the greatest DPPH radical scavenger of 81.01% and the lowest one is from isolate Aspergillus sp., number 1 from white branch shoot of 5 months which had an activity of 68.72%. This result indicated that surian have many kind of endophytic fungus and some of are potential for producing antioxidant compound.
  Intan Taufik , Dea Indriani Astuti , Isty Adhitya Purwasena and Wuddan Nadhirah Rodiana
  Background and Objective: Microbial accumulation in oil industry's pipeline system would eventually leads to biofilm formation, which could initiate biocorrosion. Biofilm-biocorrosion caused great loss in industry and is essential to be included in mitigation program. Essential oils extracted from plants are known to have anti-microbial properties. This study aimed to further investigate the effect of lemongrass (Cymbopogon citratus) essential oil in emulsion and microemulsion form against biofilm in formation water environment. Materials and Methods: Thermodynamic stability of microemulsion was observed with centrifugation, heating-cooling cycle and freeze-thaw cycle method and confirmed with particle size measurement. Results: Lemongrass essential oil treatment was able to prevent both biofilm and planktonic bacterial growth and eradicate biofilm. Minimum inhibitory concentration (MIC) of emulsion was observed at essential oil concentration of 0.06% (v/v). The minimum biofilm inhibitory concentration of emulsion and microemulsion assayed on carbon steel were 0.06 and 0.03%, respectively. Minimum biofilm eradicating concentration of emulsion and microemulsion were both 1% with eradication percentage of 53.03 and 88.39%, respectively. Biocorrosion mitigation potential of lemongrass essential oil was most effective (96.786% inhibition) at 2% (v/v) after 6 h of exposure. Conclusion: Essential oil in emulsion and microemulsion form could perform as alternative to chemical biocide in mitigating biofilm-biocorrosion.
  Pingkan Aditiawati , Akhmaloka , Dea Indriani Astuti , Sugilubin and Megga Ratnasari Pikoli
  Coal as fuel should be necessarily pre-treated by desulfurization in order to prevent excessive emissions of sulfur dioxide, a precursor of acid rain. Organic sulfur in coal can be eliminated by microbial action through the technology known as biodesulfurization. Source of microorganisms in the present study was coal mine soil in which microorganisms have been adapted to use the sulfur in coal. Coal mine in South Sumatra was choosen as source of microorganisms in this study, because it is an area in Indonesia with the largest of subbituminous coal reserves. The microorganisms were activated as mixed culture by culturing the soil sample in mineral salt medium containing subbituminous coal as the sole sulfur. Desulfurization activities were examined by using three variations of the initial coal concentration, i.e., 10, 15 and 20% weight per volume. Growth and activity of the mixed culture on the subbituminous coal were monitored by measuring of medium pH, cell concentration, sulfate and organic sulfur concentration. The result showed that desulfurization activity of the mixed culture on 15% of coal was able to reduce sulfur up to 82.36%. Isolation and identification of the mixed culture based on genotypic and phenotypic characterizations revealed that members of the mixed culture were identified as genera of Enterobacter, Lelcersia and Bacillus. Observation on growth curves showing that the culturable isolates grew in at least three overlapping stages when using coal as sulfur source suggested that the members of the consortium worked alternately on coal as substrate.
  Keukeu K. Rosada , Nur F. Afianti , Dea Indriani Astuti , Gede Suantika and Pingkan Aditiawati
  Bacterial communities in planktonic cells and biofilm at Saguling Hydro Power were investigated using Denaturing Gradient Gel Electrophoresis (DGGE) technique. Physicochemical characteristic of aqueous medium indicated that the water source was classified as moderately polluted (eutrophic). The study inferred that isolates in biofilm mostly derived from the planktonic cells and the Mann-Withney U tests showed that there was no significantly difference between the bacterial communities of planktonic cells and biofilm. The 16S rRNA sequences revealed that bacteria recovered from the planktonic cells were affiliated with Betaproteobacteria and Bacteroidetes phyla. Meanwhile, the sequences bacteria revealed from biofilm were closed to Betaproteobacteria, Alphaproteobacteria and Gammaproteobacteria groups. Overall, the majority of microbes identified from the two samples were belong to Betaproteobacteria group.
  Keukeu K. Rosada , Navisan Najia , Rahma Widya Ningrum , Dea Indriani Astuti , Gede Suantika and Pingkan Aditiawati
  Background and Objective: Biofilm plays an important role in causing microbial corrosion. One of prerequisites for microbes as energy source to grow and to form biofilm is carbon source. The purposes of this study were measuring the ability of biofilm community sampled from Saguling hydro power in utilizing carbon sources and assessing culturable heterotrophic of bacterial community from those biofilm. Materials and Methods: Biolog EcoPlateTM and culture-dependent approach were used to assess biofilm community. Results: Heterotrophic bacteria in biofilm have the ability to use 30 different carbon sources consistently. The source of carbon used by this community at the highest rate are N-acetyl-D-glucosamine from carbohydrates group, 2-hydroxybenzoic acid from carboxylic and kenotic acids, glycogen from polymers group and L-serine from the amino acid group at the rate of 0.16, 0.05, 0.14 and 0.09 absorbance U h–1 respectively. Whereas the carbon sources with high consumption are as follow: Pyruvic acid methyl ester, β-methyl-D-glucoside, D-mannitol and N-acetyl-D-glucosamine from carbohydrates group; D-galacturonic acid, 2-hydroxybenzoic acid, D-glucosaminic acid and D-malice acid from the group of carboxylic and kenotic acids; tween 40 and 80 as polymers; L-argentine, L-asparagines, L-serine, L-heroine and glycol-L-glutei from amino acids group. Furthermore, culturable bacterial community of those biofilm were dominated by Gram-negative bacteria, consisted of five common/heterotrophic bacteria, two manganese bacteria, two nitrifying bacteria, three iron bacteria and three sulfate reducing bacteria. Conclusion: Bacterial community of biofilm from Saguling hydro power which were dominated by Gram-negative bacteria have the ability to use various carbon sources and degrade glycogen.
  Gede Suantika , Alissa Diany Putri , Yovita Astuti Djohan , Fahma Fiqhiyyah Nur Azizah , Dea Indriani Astuti and Pingkan Aditiawati
  Background and Objective: The impact of environmental factors on the B vitamins (B1, B2, B6 and B12) content of marine diatom Skeletonema costatum has not yet been evaluated so far. Here, we aim to optimize the B vitamins production (vitamin B1, B2, B6 and B12) through culture of S. costatum on different salinity levels as well as light intensity exposures. Materials and Methods: The marine diatom Skeletonema costatum was cultured in different salinity levels (24, 29 and 34 g L–1) to optimize B vitamins production, prior to exposure to different light intensity levels (20, 34 and 47 μmol m–2 sec–1) for 3 days in f/2 medium. Results: Twenty four grams per liter salinity exposure produced the highest vitamin B1, B6 and B12 content of 90.08±2.6, 410.03±12.97 and 61.22±27.67 μg g–1, respectively. When cultivated either below or above light intensity of 34 μmol m–2 sec–1, vitamin B1, B6 and B12 content decreased. The highest total B vitamins obtained at 34 μmol m–2 sec–1 was 563.46 mg L–1 (vitamin B1: 90.08±1.48 μg g–1, vitamin B2: 2.87±0.79 μg g–1, vitamin B6: 410.03±12.97 μg g–1 and vitamin B12: 61.22±27.67 μg g–1). Conclusion: Optimum growth, biomass and total B vitamins produced was achieved by culturing at salinity of 24 g L–1 and light intensity 34 μmol m–2 sec–1. So far, optimum growth, biomass and total B vitamins produced was achieved by culturing at salinity of 24 g L–1 and light intensity 34 μmol m–2 sec–1. Note that when aiming at high vitamin productivities, it is better to culture S. costatum in a two step process: A nutrient sufficient phase in optimum environmental growth conditions to produce enough cells (e.g., salinity, illumination, pH, temperature, supply of CO2 and nutrients etc.), followed by suitable stress to stimulate B vitamins synthesis in a controlled manner.
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