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"ABSTRACTXylitol is five-carbon polyol sugar which widely used as a sweetener in food and pharmaceutical.Xylitol production by chemical procedures using high pressure and temperature also neededextensive purification are less cost-effective in production. Fermentation which has more advantageswith lower cost due tocheaper substrate and the non-necessity of xylose purification. The purposes ofthis research were to find optimum condition for xylitol production with particular variable such assubstrate concentration, aeration, methanol and nitrogen sources addition. Oil palm empty fruitbunch hydrolyzates containing xylose was fermented into xylitol by Debaryomyces hansenii UICC Y-276 at room temperature. Fermentation was carried out at 200 rpm for 72 hours. Then, xylose andxylitol were determined by HPLC with RI detector and LiChrosorb® NH2 (4 mm x 125,00 mm, 5μm)column. Acetonitrile-water was used as a solvent, 20 mL sample volume was injected at flow rate of1,0 mL/min at room temperature. The optimum fermentation conditions was obtained in a state ofsemi-anaerobic condition (1 : 2.5) with 10,0 % (w/v) xylose concentration. Meanwhile with theaddition of various concentration of methanol and nitrogen sources, it was obtained that 1,5 %methanol and 0,5 % ammonium sulfate gave high yield of xylitol production. The best result for yieldxylitol production was 31,83 %."

"Microbial Desalination Cell (MDC) 3 Chamber merupakan salah satu teknologi desalinasi yang tidak memerlukan listrik dalam menjalankan desalinasi. Namun, lamanya waktu desalinasi dan rendahnya salt removal yang dihasilkan masih menjadi kendala. Penelitian dilakukan dengan menguji coba penggunaan Debaryomyces hansenii ke MDC 3 Chamber yang baru dengan rasio volume anoda : volume garam : volume katoda yaitu 2:1:2 dan 9:1:9 dan substrat yaitu glukosa serta larutan NaCl awal 30 g/L. Variasi yang digunakan dalam penelitian yaitu rasio kultur terhadap substrat dan kenaikan volume kultur dan substrat. Untuk masing-masing MDC 3 chamber, dilakukan pengukuran salinitas dan tegangan listrik tiap jam. Data kemudian diolah untuk mendapatkan nilai salt removal sedangkan estimasi parameter kinetika Monod yaitu Pmax dan KS menggunakan Solver. Hasil penelitian menujukkan bahwa pada kondisi optimum MDC 3 chamber yaitu pada kenaikan volume kultur dan substrat sebesar 1,5 kali dengan menggunakan Debaryomyces hansenii terbukti efektif dan cukup cepat dalam menurunkan salinitas (salt removal) yaitu 55,03 % pada jam ke-40 untuk rasio volume chamber 9:1:9 dan 30, 55 % pada jam ke-25. untuk rasio volume chamber 2:1:2. Besarnya konsentrasi awal substrat yang digunakan berpengaruh pada densitas daya yang dihasilkan. Persamaan Monod untuk kinetika MDC 3 chamber dapat diaplikasikan dengan baik pada MDC 3 chamber rasio volume chamber 2:1:2 Saccharomyces cerevisiae dan MDC 2:1:2 - Debaryomyces hansenii dengan nilai Pmax dan KS yaitu 0,103 W/m3 ; 1,13 x 104 mg/L ; 0,151 W/m3 ; 1,09 x 105 mg/L. Namun, persamaan Monod tidak dapat diaplikasikan untuk MDC 3 chamber rasio volume 9:1:9 - Debaryomyces hansenii.

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Microbial Desalination Cell (MDC) 3 Chamber is one of the desalination technology that does not require electricity to run desalination. However, the length of time for desalination and low of salt removal still a constraint. The study was conducted with the use of Debaryomyces hansenii tested to MDC 3 new Chamber with anode volume ratio: the volume of salt: the volume of 2:1:2 and 9:1:9 cathode and the substrate is glucose and initial NaCl 30 g / L. Variation used in the study of culture to substrate ratio and the increase in the volume of the culture and the substrate. For each of the 3 chamber MDC, salinity measurements and the power supply voltage were taken every hour. The data is then processed to obtain salt removal while estimates of the value of the Monod kinetic parameters, namely Pmax and KS using Solver.

The results showed that the optimum conditions MDC 3 chamber culture is on the rise and substrate volume of 1.5 times using Debaryomyces hansenii proven effective and fast enough to lower the salinity (salt removal) is 55.03% at the 40th hour for the ratio chamber volume 9:1:9 and 30, 55% at the 25th hour. to chamber volume ratio 2:1:2. The magnitude of the initial concentration of the substrate that is used affects the generated power density. Monod equation to the kinetics of MDC 3 chamber can be applied to both the MDC 3 chamber volume ratio 2:1:2 Saccharomyces cerevisiae and MDC 2:1:2 - Debaryomyces hansenii and Pmax value is 0.103 W/m3 ; KS; 1.13 x 104 mg/L ; 0.151 W/m3 ; 1.09 x 105 mg/L. However, the Monod equation can not be applied to MDC 3-chamber volume ratio 9:1:9 - Debaryomyces hansenii."

"Desalination is a way to process sea water with a high salinity level, which makes water non-consumable. Various desalination technologies, such as distillation, vapor compression, and reverse osmosis, have been developed but require energy and large financial investments. Microbial desalination cell (MDC) is a modified desalination technology of a microbial fuel cell that can remove salt content in water with the help of microorganisms through organic matter degradation. This research used Debaryomyces hansenii to degrade organic material in the anode chamber. The ratio of the volume chamber, the volume ratio of culture:substrate, and the volume progression of the culture and substrate were evaluated in terms of salt removal and electricity generation. This research shows that MDC using a 9:1:9 ratio of the volume chamber, a culture:substrate ratio of 2:3 (v/v), and a volume progression of the culture and substrate of 1.5 times gave the best desalination performance: a salt removal level of 55.03%"

"Xilitol merupakan gula alkohol jenis pentitol, yang jalur metabolismenya tidak dipengaruhi oleh insulin, serta memiliki aktivitas anti kariogenik. Produksi xilitol dengan cara fermentasi dinilai lebih ekonomis dan praktis dibandingkan dengan cara lainnya. Salah satu khamir yang memiliki potensi besar untuk fermentasi xilitol adalah Debaryomyces hanseniii osmotoleran. Proses reduksi xilosa menjadi xilitol dikatalisis oleh xilosa reduktase (XR), sedangkan proses oksidasi xilitol menjadi xilulosa dikatalisis oleh xilitol dehidrogenase (XDH). Pada penelitian sebelumnya, telah dilakukan pre-treatment kondisi osmotik tinggi pada khamir D. hansenii, namun ternyata kemampuan biokonversi khamir tersebut masih rendah, sehingga dibutuhkan cara untuk meningkatkan aktivitas biokonversinya. Salah satu upaya untuk meningkatkan aktivitas biokonversi khamir D. hansenii adalah dengan mutagenesis menggunakan etil metan sulfonat sebagai mutagen kimia. Inkubasi mutasi dilakukan selama 20, 45, dan 60 menit pada suhu 30oC dan kecepatan pengadukan 70 rpm. Mutan auksotrop diisolasi dengan media minimum, kemudian mutan yang diperoleh diuji nilai aktivitas XR dan XDH-nya. Hasil terbaik ditunjukkan oleh mutan EMS 60 (waktu inkubasi mutasi 20 menit), dengan nilai uji aktivitas XR tertinggi yang disertai dengan nilai uji aktivitas XDH terendah.

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Xylitol is a sugar alcohol, pentitol type, not affected by the metabolic pathway of insulin and also have anti-cariogenic activity. Xylitol production by fermentation process is prefered, because this process is more economical and simple. One of the potential yeast for xylitol fermentation is Debaryomyces hanseniii osmotolerant. The reduction process of xylose to xylitol is catalyzed by xylose reductase (XR), whereas the oxidation process from xylitol to xylulose catalyzed by xylitol dehydrogenase (XDH). In the previous experiment, a pre-treatment of high salt concentration has given to Debaryomyces hansenii, but the bioconversion activity is still low, so we need some modification to increase the bioconversion activity. One method to increase the bioconversion activity of D. hansenii is to perform mutagenesis using ethyl methane sulphonate as a chemical mutagen. Incubation mutation done for 20, 45, and 60 min at 30°C and at 70 rpm stirring speed. Auksotrop mutants were isolated with minimum media, then the XR and XDH activity of the mutants were tested. The best result was shown by the A mutant (mutations incubation time 20 minutes), with the value of the highest XR enzyme activity and the lowest XDH enzyme activity."

"Penelitian bertujuan membuat pollen substitute (PS) yang disukai dan dapat meningkatkan produktivitas lebah madu A. cerana. Pollen substitute dibuat dengan bahan dasar tepung kedelai dan susu skim. Pada penelitian ini A.cerana diberikan tiga macam pollen substitute, yaitu PS A (mengandung bahan dasar, Debaryomyces hansenii CR133, madu); PS B (mengandung bahan dasar, sirup gula); PS C (mengandung bahan dasar, madu). Pemberian PS selama 20 hari, dan lebah dibiarkan mencari serbuk sari dan nektar di alam. Koloni kontrol tidak diberi PS. Hasil penelitian menunjukkan bahwa PS yang dibuat memenuhi kriteria sebagai PS yang baik. Apis cerana menyukai PS A dan PS C dengan tingkat konsumsi yang lebih tinggi dibandingkan PS B. Pemberian semua jenis PS meningkatkan keliling (0,3--4,5 cm per hari) dan jumlah honeycomb. Pada kontrol terdapat kenaikan keliling honeycomb (0,2--0,5 cm per hari), namun tidak ada penambahan jumlah honeycomb. Secara umum, lebah pekerja yang diberi PS dan kontrol mengalami kenaikan berat badan (5--56,94%).

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The research aimed to make pollen substitutes preferred by and increase the productivity of A. cerana. Basic ingredients of pollen substitutes (PS) were soy flour and skim milk. There were three types of pollen substitutes, i.e. PS A (contained basic ingredients, Debaryomyces hansenii CR133, honey); PS B (basic ingredients, sugar syrup); and PS C (basic ingredients, honey). The pollen substitutes were fed to colonies of A. cerana for 20 days, but they were allowed to forage on flowers. No PS was given to the control colonies.

The results showed that A. cerana preferred PSA and PS C to PS A. Increases of circumference and number of honeycombs were observed in colonies fed with all types of PSs (0,3--4,5 cm/day). There was an increase of the circumference of honeycombs in the control (0,2--0,5 cm/day), but there was no addition of new honeycomb. Generally, the weight of individual worker bees increased in colonies fed with PSs and control (5--56,94%)."