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Pengaruh Kepadatan Awal Inokulum terhadap Kualitas Kultur Chaetoceros gracilis (Schütt) pada Sistem Batch Gede Suantika; Pingkan Adityawati; Dea Indriani Astuti; Yusup Sofyan
Jurnal Matematika & Sains Vol 14, No 1 (2009)
Publisher : Institut Teknologi Bandung

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Abstract

Chaetoceros gracilis (Schütt) is a common live food used in white shrimp Litopenaeus vanamei larviculture that is commonly produced by using batch culture system. The aim of this study was to evaluate the effect of different initial densities inoculums to obtain the optimum quality of C. gracilis culture in batch culture system. Based on the result from step 1, the highest cell density of 9,85x106 ± 5,00x105 cells/mL was obtained in the culture with inoculum initial density of 1,0x105 cells/mL. At step 2, the highest cell density of 9,87 x 106 ± 2,00 x 105 cells/mL was obtained in the culture with inoculum initial density of 1,0x105 cells/mL and it was significantly (p
Microbial Succession and Chemical Characteristics in Fermentation of Ambonese Arrack (Sopi), Traditional Beverage from Maluku Mahulette, Ferymon; Astuti, Dea Indriani
Biosaintifika: Journal of Biology & Biology Education Vol 12, No 2 (2020): August 2020
Publisher : Department of Biology, Faculty of Mathematics and Sciences, Semarang State University . Ro

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/biosaintifika.v12i2.23791

Abstract

Ambonese arrack is one of the traditional fermented beverage product in Maluku, Indonesia. The microbiological research of this beverage that is processed using coconut sap as raw material has never been done before. The research aimed to analyze the microbial succession and chemical characteristics during fermentation of Ambonese arrack. The sample of coconut sap was taken from traditional producer in Mahia village, Ambon. The dominant microbes in the fermentation of Ambonese arrack were Pichia polymorpha and Kloeckera javanica. The highest numbers of these two microbes was obtained after 15 hours fermentation (9.6 log Cfu/mL and 9.9 Cfu/mL, respectively). The sugar content decreased from 593.3 mg/L to 474.3 mg/L, whereas ethanol content increased from 0.0018 g/L to 0.0100 g/L. The pH value decreased from 4.70 to 3.10. The research has isolated indigenous microbes in Ambonese arrack fermentation which was considered as novelty. The bacteria that play a role in fermentation can be used as a starter in the fermentation of various beverage products, especially Ambonese arrack. The results of this research can improve the quality of this fermentation product in the future.
PENGEMBANGAN MODEL PENERIMAAN BIOPESTISIDA (Studi Kasus Pada Petani Sayuran di Desa Cipada Kecamatan Cisarua Kabupaten Bandung Barat) Saepudin Saepudin; Dea Indriani Astuti
Jurnal Sosioteknologi Vol. 11 No. 27 (2012)
Publisher : Fakultas Seni Rupa dan Desain ITB

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Abstract

Pertanian tradisional ditandai penggunaan pestisida sintetik yang tinggi sehingga meninggalkan residu pestisida sintetik. Di lain pihak, kesadaran konsumen untuk mendapatkan produk pertanian yang bebas dari pestisida sintetik cenderung meningkat sehingga diperlukan penggunaan pestisida yang ramah lingkungan. Biopestisida merupakan pestisida yang ramah lingkungan, tetapi penggunaan oleh petani di lapangan cenderung rendah. Oleh karena itu, diperlukan suatu penelitian mengenai kesediaan petani menggunakan biopestisida dan pengembangan model penerimaan biopestisida oleh petani. Penelitian ini bertujuan untuk mengukur kesediaan petani sayuran di Desa Cipada untuk menggunakan biopestisida dan mengembangkan suatu model penerimaan biopestisida oleh petani sayuran. Metode penelitian menggunakan metode survei wawancara terstruktur dengan jumlah petani sayuran di Desa Cipada sebanyak 30 orang. Penerimaan biopestisida oleh petani diasumsikan dalam dua kondisi. Pada kondisi pertama, biopestisida memiliki performa yang sama dengan pestisida sintetik. Pada kondisi kedua, biopestisida memiliki performa lebih rendah 10%-20% dibandingkan dengan pestisida sintetik. Metode pengambilan sampel menggunakan metode pengambilan sampel contoh kemudahan. Analisis data menggunakan metode deskripsi dengan statistik deskriptif. Hasil penelitian menunjukkan bahwa pada kondisi pertama 97% petani sayuran di Desa Cipada menyatakan kesediaannya menggunakan biopestisida, sedangkan 3% lainnya tidak bersedia. Faktor peningkat penerimaan biopestisida adalah tingkat pendidikan, lama pengalaman bertani, persepsi penurunan keefektivan pestisida, pengetahuan responden tentang produk biopestisida, dan luas lahan. Faktor pengurang penerimaan biopestisida adalah status kepemilikan lahan, persepsi kecenderungan serangan hama dan penyakit yang meningkat, persepsi resistensi hama, persepsi kehadiran hama baru, persepsi perubahan musim, pengetahuan responden pada bahaya pestisida, pengalaman komplikasi kesehatan setelah penggunaan pestisida, dan pendapatan dari pertanian. Faktor pengurang ini harus diperhatikan dalam proses pengenalan biopestisida. Pada kondisi kedua, persentase petani sayuran di Desa Cipada yang bersedia menggunakan biopestisida adalah 40% dan 60% lainnya menyatakan tidak bersedia. Kata kunci : biopestisida, petani sayuran, penerimaan biopestisida, pengembangan model penerimaan biopestisida. Traditional agriculture is characterized by the high use of chemical pesticide (highly) so that it leaves chemical pesticide residues. On the other hand, consumers awareness to get free of chemical pesticide agriculture product tends to increase so that the use of environmentally friendly pesticides is required. Biopesticides' are environmentally friendly pesticides, but actually the number of farmers who use it is still low. Therefore, we need to develop a biopesticides acceptance model by vegetable farmer. This research aims to measure the willingness of acceptance biopesticides by vegetable farmer in Cipada, and develop a biopesticides acceptance model. We use the structured interviews survey method with 30 respondents as the research method. Acceptance of biopesticides by the vegetable farmers in Cipada is assumed into two conditions. In the first condition, biopesticides have the same performance with chemical pesticides. In the second conditions, biopesticides have a perform ance of 10%-20% lower than chemical pesticides. Convenience sampling is used to take the samples in this research. To analyze the data, we use descriptive statistic. The results of the research show that in first condition, 97% of the respondents are willing to accept biopesticides, while 3% of the respondents are not. The increasing factors of biopesticides acceptance are education level, years of farm experience, decreasing of pesticides efectivity perseption, vegetable farmer knowledge about biopesticides, and farming area. Mean while, the decreasing factor of biopesticides acceptance are farming area ownership, increasing pest attack and plant disease perception, pest resistance perception, new pest presence perception, weather change perception, vegetable farmer knowledge about the hazard of pesticides, experience of healthy risk by using of pestisicides, and farmer income. Then in the second conditions, the percentage of respondents who are willing to use biopesticides is 40% and the others are not willing to use. Key words: biopesticides, vegetable farmers, acceptance of biopesticides, developing of biopesticides acceptance model.
Indigenous Microbial Biostimulation for Microbial Enhanced Oil Recovery through Oil Degradation with Variation in Nutrent Concentrations Handaruni, Rika; Astuti, Dea Indriani; Purwasena, Isty Adhitya; Afifah, Lulu Nur
Makara Journal of Science
Publisher : UI Scholars Hub

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Abstract

Oil production in Indonesia has been declining since 2002, and this decline is incompatible with the high oil consumption in Indonesia. As such oil production in Indonesia should be improved. Biostimulation in microbial enhanced oil recovery involves environmental modification to stimulate microbial growth within a reservoir by adding limiting nutrients. Variation in C, N, and P concentrations injected to reservoirs can induce different responses from indigenous microbes and increase oil recovery. In this study, molasses, urea and diammonium phosphate were used as nutrients injected to a reservoir for biostimulation. Biological, physical and chemical characteristics after biostimulation were observed and bacterial growth was monitored up to 42 days. The physical characteristics observed were pH, oil viscosity, and interfacial tension. Gas chromatography mass spectrometry was performed to determine the chemical characteristics of oil. Results showed that the addition of nutrients at various concentrations yielded different production patterns of metabolites. The addition of urea and diammonium phosphate induced biosurfactants overproduction and increase hydrocarbon degradation of by bacteria. Therefore, hydrocarbons were degraded for the first 14 days, and polymerized again on days 14 to 42.
Production and Characterization of Thermoalkaliphilic Xylanase from Bacillus halodurans CM1 on Degumming Process of Ramie (Boehmeria nivea L.Gaud)Fiber as Textile Raw Material DEWI NANDYAWATI; DEA INDRIANI ASTUTI; NIKNIK NURHAYATI; ASEP RISWOKO; IS HELIANTI
Microbiology Indonesia Vol. 15 No. 3 (2021): September 2021
Publisher : Indonesian Society for microbiology

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (972.873 KB) | DOI: 10.5454/mi.15.3.3

Abstract

Ramie fiber is a potential raw material to substitute imported raw materials such as cotton. Due to its higher hemicellulose content, ramie fiber required hydrolysis in a process called degumming. Enzymatic degumming is environmentally friendly compared to traditional process which using chemicals. Alkalithermophilic xylanase have high ability in hemicellulose hydrolysis. The production of xylanase was conducted by submerged fermentation of Bacillus halodurans CM1 in 20L bioreactor using Mamo and corncob medium with optimum conditions at 50°C, pH 9, 150 RPM and 1 vvm. The optimum specific activity of xylanase measured by Bailey method at 70°C and pH 9 is 475.41 U/mg. Xylanase was stable at 50°C, pH 9 and relatively stable to K+, Na2+, Co2+ and Ca2+ metal ions and Triton-X, Saba dan Tween-80 surfactants. Degumming process was carried out by immersing ramie fibers in formulated degumming solution with vlot 1:20 at 50°C, 150 RPM and 180 minutes. The enzymatic degumming process may substitute or reduce the use of chemicals due to its significant effect on ramie fiber quality. Enzymatic and chemical degumming process reduce the weight of Ramie Fiber to 7.23 %, and 7.72 %, slightly higher than enzymatic degumming 7.15%. Enzymatic degumming maintains tensile strength at 27.51 %. Whiteness index enhanced to 2.99% enzymatically and 3.49% chemically. Keywords: Bacillus halodurans CM1, enzymatic degumming, ramie fiber, textile industry, thermoalkaliphilic xylanase