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"Xilitol merupakan gula poliol berkarbon lima yang dimanfatkan sebagai pemanis pengganti gula dalam industri makanan dan farmasi. Produksi xilitol secara kimiawi dilakukan dengan menggunakan tekanan dan temperatur yang tinggi serta memerlukan pemurnian berulang sehingga metode ini dianggap kurang ekonomis dalam biaya produksi. Maka dari itu, dilakukan produksi xilitol dengan cara fermentasi yang dianggap lebih ekonomis karena sumbernya dapat lebih murah dan tidak memerlukan pemurnian yang berulang. Fermentasi dilakukan dengan memanfaatkan hidrolisat limbah industri tandan kosong kelapa sawit sebagai substrat oleh khamir Debaryomyces hansenii UICC Y-276. Tujuan penelitian ini adalah, menghasilkan xilitol dengan fermentasi memamanfaatkan hidrolisat limbah industry tandan kosong kelapa sawit yang mengandung xilosa. Hemiselulosa tandan kosong kelapa sawit dihidrolisis dengan katalis asam oksalat dan dioptimasi mengunakan metode statistik response surface method. Optimasi kondisi fermentasi produksi xilitol meliputi; konsentrasi metanol, jenis sumber nitrogen dan konsentrasi sumber nitrogen. Kondisi optimal hidrolisis berdasarkan response surface methode adalah 8 gram bobot tandan kosong kelapa sawit dalam 35 ml (1:5 b/v), 75 menit, dan konsentrasi asam oksalat 6%, serta didetoksifikasi selama 75 menit oleh arang aktif 2%. Xilosa yang dihasilkani sekitar 28 g/L. Yield value xilitol terbesar ditunjukan pada kondisi fermentasi dengan penambahan metanol 1,5% dan ammonium sulfat sebagai sumber N, yaitu 29,68%.

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Xylitol is five-carbon polyol sugar which widely used as sweetener in food and pharmaceutical. Production xylitol by chemical procedures using high pressure and temperature and also needed extensive purification are less cost-effective in production. Fermentation which has more advantages with lower cost caused of cheaper substrate and the non-necessity of xylose purification. Fermentation for this research utilizing waste oil palm empty fruit bunch fiber hydrolysate by Debaryomyces hansenii UICC Y-276 yeast.

The purpose of this research is to produce xylitol with fermentation method, utilizing waste biomass hydrolysate from oil palm empty fruit bunches containing xylose. Hemicellulose from oil palm empty fruit bunches was hydrolized by oxalic acid and also optimized using RSM statistic methode. Optimization of fermentation conditions for xylitol production are optimization methanol concentration and nitrogen source.

Optimum conditions for hydrolysis of oil palm empty fruit bunches fiber obtained from response surface method were 8 gram in 35 ml (1:5 b/v), 75 minute, and dan 6% oxalic acid concentration with 75 minute detoxification by 2% carchoal adsorben give xilose concentration 28 g/L. The highest yield value of xylitol, 29,68 % given by fermerntation condition with the addition of 1,5% methanol and ammonium sulfate as nitrogen source."

"ABSTRACTXylitol is a five-carbon polyol sugar. It has many healthy benefits and is widely used in food, pharmaceutical, and healthcare. Natural sources with abundant carbon such as lignocellulose can be used for xylitol production. One of the potencial sources with high prevalency in Indonesia is water hyacinth. It is known as weeds and has not been fully utilized by people. The aim of this research was the utilization of water hyacinth which contains hemicellulose as a substrate in the bioconversion of xylose into xylitol by yeast cells Debaryomyces hansenii. Stages of processing include the optimization of water hyacinth hydrolysis using autohydrolysis method and optimization of fermentation conditions. Xylose and xylitol were determined by HPLC with RI detector and LiChrosorb® NH2 (4 mm x 125,00 mm, 5μm) column. Acetonitrile-water (90:10, v/v) was used as a solvent. 20 μL sample volume was injected at flow rate of 1.0 mL/min and room temperature. The results showed that optimum conditions for the acquisition of xylose were obtained through autohydrolysis methods for 75 minutes with 1:15 water hyacinth and water ratio and posthydrolysis for 45 min using 4% sulfuric acid. Xylose concentration in hydrolyzate obtained was 25.55 g/L. The optimum fermentation condition for xylitol production was achieved by four day cultivation, limited aeration condition, and addition of metal ions CaCl2.2H2O 0.01%. The yield of xylitol obtained using those conditions was 77.43 %. "

"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 %."

"Keberhasilan produksi apoptin rekombinan dalam bentuk native pada penelitian sebelumnya (Khalid, 2012) membuka jalan untuk mengembangkan produksi protein antikanker ini ke skala yang lebih besar. Di dalam studi ini, dilakukan optimasi kultivasi bakteri rekombinan apoptin dalam stirred tank fermentor dan bakteri yang digunakan adalah bakteri Bacillus subtilis 168 rekombinan apoptin hasil transformasi dengan sistem Gateway menggunakan plasmid pOXGW12His8Arg. Parameter yang dioptimasi adalah konsentrasi induksi xylose, kecepatan agitasi dan laju aerasi. Variasi konsentrasi induksi xylose dilakukan dalam shake flasks dengan volume kultur 100 ml dengan konsentrasi 0-5% b/v sedangkan variasi kecepatan agitasi dan laju aerasi dilakukan dalam stirred tank fermentor dengan volume kultur 3L dengan kecepatan dan laju masing-masing adalah 150-250 rpm dan 0,5-1,5 NL/min. Hasil yang didapat adalah pertumbuhan bakteri optimum dicapai pada konsentrasi xylose 1% b/v, kecepatan agitasi 250 rpm, dan laju aerasi 1,5 NL/min dengan nilai laju pertumbuhan spesifik bakteri untuk masing-masing variasi adalah 0,628 h-1; 0,630 h-1; dan 0,747 h-1.

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The success of recombinan apoptin production in native form in the previous research (Khalid, 2012) open the way to develop this anticancer protein production to the larger scale. In this study, optimization of recombinant apoptin bacteria cultivation is carried out in a stirred tank fermentor using Bacillus subtilis 168 with plamid pOXGW12His8Arg which transformed by Gateway method. The optimized parameters are xylose-inducer concentration, agitation speed, and aeration rate. The xylose-inducer concentration variation is carried out in a shake flasks with 100 ml volume broth, while the agitation speed and aeration rate variation is carried out in a stirred tank fermentor with 3L volume broth. The xylose concentration is varied between 0-5% w/v, while agitation speed and aeration rate are varied between 150-250 rpm and 0,5-1,5 NL/min respectively. The best condition in this cultivation is 1% w/v of xylose, 250 rpm of agitation speed and 1,5 NL/min of aeration rate giving the specific growth rate value for each parameter of 0,628 h-1; 0,630 h-1; dan 0,747 h-1 respectively."

"Xilitol merupakan senyawa poliol alami yang banyak ditemukan pada buah dan sayuran. Sebagai pemanis atau pengganti gula, xilitol diperbolehkan penggunaanya dalam bidang farmasi, produk kesehatan oral, dan makanan. Produksi xilitol dapat dilakukan melalui pendekatan bioteknologi; proses fermentasi. Tujuan dari penelitian ini adalah memperoleh hidrolisat tandan kosong kelapa sawit dengan konsentrasi xilosa yang tinggi, serta memperoleh kondisi optimum fermentasinya menjadi xilitol menggunakan Debaryomyces hansenii. Optimasi hidrolisis tandan kosong kelapa sawit dilakukan menggunakan katalis asam oksalat, sedangkan optimasi kondisi fermentasi produksi xilitol meliputi: konsentrasi substrat, aerasi, dan penambahan ion logam. Kondisi optimum hidrolisis dengan konsentrasi xilosa tertinggi didapatkan pada kondisi hidrolisis menggunakan 6,0 % asam oksalat dengan suhu 121°C dan tekanan 1 atm, selama 60 menit. Sedangkan dalam optimasi kondisi fermentasi, didapatkan bahwa kondisi aerasi optimum diperoleh pada keadaan semi anaerob (volume 100,0 mL dalam erlenmeyer 250,0 mL), yang menghasilkan xilitol sebesar 41,74 g/L dari konsentrasi substrat sebesar 10,0 %. Selanjutnya, dengan penambahan ion logam menyebabkan terjadi penurunan produksi xilitol. Secara berturut-turut, dihasilkan yield value sebesar 4,90 % dalam penambahan ZnSO4.7H2O, 7,58 % dalam penambahan FeSO4.7H2O, 5,59 % dalam penambahan CaCl2.2H2O, dan 6,12 % dalam penambahan CuSO4.5H2O.

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Xylitol is a polyol compound which is naturally found in many fruits and vegetables. As a sweetener or sugar substitute, xylitol is allowed for its use in pharmaceutical, oral health care product, and foods. Production of xylitol can be done through biotechnological approache; the fermentation process.

The purposes of this research is to obtain hydrolyzates of oil palm empty fruit bunch with high xylose concentration, and to obtain optimum fermentation condition into xylitol using Debaryomyces hansenii. Hydrolysis optimization of oil palm empty fruit bunch was done by using oxalic acid catalyst, while the optimization of fermentation condition for xylitol production included: substrate concentration, aeration, and metal ion addition.

The optimum condition of hydrolysis with highest xylose concentration was obtained in hydrolysis condition that used 6.0 % oxalic acid with temperature of 121°C and pressure of 1 atm, for 60 minutes. While for the optimization of fermentation conditions, it was found that the optimum aeration condition was obtained in a state of semi-anaerobic condition (100.0 mL of medium volume in erlenmeyer of 250.0 mL), the xylitol yield was 41.74 g/L from 10.0 % substrat concentration.

Furthermore, with the addition of metal ions inducing a reduction of xylitol production. Succesively, the result of its yield value are 4.90 % in addition of ZnSO4.7H2O, 7.58 % in addition of FeSO4.7H2O, 5.59 % in addition of CaCl2.2H2O, and 6.12 % in addition of CuSO4.5H2O."

"Xylitol is a sugar alcohol used as a sweetener in the food industry. Xylitol can be produced from D-xylose using a fermentation process, but it then needs to be separated from the other components of the fermentation broth (e.g., metabolic products, residual substances, biomass cells, and mineral salts), before being purified as xylitol crystals. Therefore, to obtain high purity xylitol, various separation processes are required. One very promising downstream processing method is membrane separation. This study evaluated membrane-based processes for the separation of biomass cells and other impurities, determined the concentration of xylitol produced from Debaryomyces hansenii yeast fermentation broth, and proposed a polysulfone ultrafiltration (UF) membrane for biomass-cell separation followed by polyamide nanofiltration (NF) to remove low-molecular-weight compounds (e.g., acetic acids) from sugars. The effects of operating pressure were examined using a fermentation broth model solution. The results showed that a higher pressure caused a higher permeate flux; however, the permeate flux’s rate flow decreased over time due to concentration polarization, and fouling in the UF and NF membranes. Nevertheless, at all pressures, UF achieved a 99% rejection of biomass cells. In addition, microscope analysis showed that no biomass cells were detected in the permeates of UF. The resulting NF concentrates revealed high xylitol retention and a beneficially lower concentration of acetic acids. The operating pressures of the UF test conditions were 1 barg and 1.5 barg, illustrating that, at a pressure of 5.5 barg, the experiments achieved reasonably high xylitol retention (above 90%) indicating negligible losses of sugar in the permeate port. Moreover, this was proven to be a feasible way to concentrate xylitol up to three times from the initial concentration of the model fermentation broth (MFB). Therefore, the results demonstrated that a two-stage combination of UF and NF is a promising system for the downstream processing of microbial xylitol production."

"Karies gigi merupakan salah satu penyakit infeksi jaringan keras gigi yang sangat banyak menyerang penduduk Indonesia, dengan tingkat prevalensi lebih dari 90%. Karies terjadi sebagai akibat ketidakseimbangan proses demineralisasi dan remineralisasi yang terjadi pada permukaan gigi, yaitu pada saat tingkat demineralisasi terjadi lebih tinggi daripada remineralisasi. Untuk menanggulangi masalah karies, diperlukan usaha preventif yang terjangkau oleh masyarakat. Salah satu agen yang dipercaya dapat mencegah terjadinya karies adalah xylitol. Penelitian-penelitian terdahulu telah menyatakan bahwa xylitol dapat meningkatkan remineralisasi. Pada penelitian ini, diteliti pengaruh penambahan xylitol pada larutan remineralisasi pada permukaan email yang didemineralisasi ditinjau dari struktur permukaan email gigi. Penelitian ini dilakukan dengan menggunakan 22 potong spesimen gigi yang dikelompokkan menjadi kelompok kontrol positif, kontrol negatif, dan perlakuan. Seluruh spesimen gigi, kecuali kelompok kontrol positif, direndam ke dalam larutan asam asetat dengan pH 4 selama 2x24 jam pada suhu 500C. Setelah itu, kelompok perlakuan dibagi ke dalam dua kelompok dan direndam kembali ke dalam larutan reminerlisasi, yang mengandung 20% dan 50% xylitol pada suhu 370C selama 2x7 hari. Seluruh sampel difoto dengan menggunakan SEM (Scaning Electron Micrograf) pada laboratorium CMPFA FTUI dan dilakukan analisis secara kualitatif. Berdasarkan hasil yang diperoleh, dapat disimpulkan bahwa xylitol dapat memicu terjadinya proses remineralisasi pada permukaan gigi yang telah mengalami demineralisasi.

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Dental caries is one of the infection diseases on the tooth. Its prevalence in Indonesia is more than 90%. Caries happened when there is unbalance condition between demineralization and remineralization process, which is higher in demineralization. To prevent the dental caries, there should be preventive programs that can be reached by all people. One agent believed to control and reduced dental caries is xylitol. This research observed the enamel surface?s structure related remineralization effects of xylitol on artificially demineralized enamel. The samples were demineralized in an acid solution with 4.0 pH level for two days. After that, they`re immersed in a remineralized solution containing 20% or 50% xylitol at 37oC for two weeks. Samples were analyzed using SEM to see the quality difference between the control samples and the other one on the enamel?s surface. SEM analyzing indicated that remineralization happened in enamel?s surfaces. The enamel?s surfaces remineralized with solution containing 50% xylitol had a better change after remineralization than the 20% did. These results mean that xylitol can avoid caries by inducing remineralization and inhibit demineralization."

"Tujuan penelitian ini adalah mempelajari pengaruh pemaparan xylitol pada email yang telah terdemineralisasi terhadap remineralisasi ditinjau dari kekerasan email. Demineralisasi dilakukan dengan larutan asam asetat 0.01 Μ (pH 4.0) pada suhu 50°C selama 2 hari. Untuk remineralisasi, sampel kemudian direndam dalam larutan remineralisasi dengan konsentrasi xylitol 20% atau 50% pada suhu 37°C selama 2 minggu. Kekerasan email dari sampel dengan dan tanpa xylitol diuji menggunakan alat uji kekerasan Vickers. Hasil menunjukkan adanya perbedaan kekerasan email antara kelompok yang diberi aplikasi larutan remineralisasi berxylitol dengan kelompok kontrolnya (p<0.05). Kelompok yang direndam dalam larutan remineralisasi ber-xylitol menunjukkan nilai kekerasan yang lebih besar daripada kelompok kontrolnya. Kekerasan email berkisar antara 423 ± 45 VHN pada kelompok larutan remineralisasi ber-xylitol 20%, sedangkan kelompok kontrolnya menunjukkan nilai 302 ± 60 VHN. Kelompok yang direndam dalam larutan remineralisasi ber-xylitol 50% menunjukkan nilai kekerasan 367 ± 70 VHN, sedangkan kelompok kontrolnya menunjukkan nilai 252 ± 100 VHN. Ini dikarenakan kemampuan xylitol untuk membentuk kompleks dengan ion-ion kalsium, hal ini membantu remineralisasi, sehingga lebih lanjut meningkatkan kekerasan dari email yang terdemineralisasi. Fungsi utama kalsium adalah untuk kekerasan tulang dan gigi.

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This study aimed to determine the effects of xylitol exposure of demineralized enamel on remineralization in terms of enamel microhardness. The demineralizing treatment was done with a 0.01 Μ acetate buffer solution (pH 4.0) at 50°C for 2 days. For remineralization, the enamel samples were then immersed in a solution with 20% or 50% xylitol at 37°C for 2 weeks. Hardness of the enamel samples with and without xylitol treatment was measured as Vickers microhardness. Results showed differences of enamel microhardness between the group that is immersed in remineralizing solutions with xylitol and the control group (p < 0.05). Groups that is immersed in remineralizing solutions with xylitol showed higher microhardness values than its control groups. The enamel microhardness ranged between 423 ± 45 VHN on samples that are immersed in remineralizing solution with 20% xylitol, while its control group showed 302 ± 60 VHN in microhardness test. Samples that were immersed in remineralizing solution with 50% xylitol showed 367 ± 70 VHN in microhardness test, while its control group result in 252 ± 100 VHN. This is caused by the xylitol?s capability to form complexes with calcium ions, which helps the remineralization process and further increase the microhardness of the demineralized enamel. The major function of calcium is to provide rigidity and strength to bones and teeth."

"Penelitian ini dilakukan untuk membuat xilitol dari limbah batang/malai sorgum manis CTY-33. Xilitol dibuat melalui proses fermentasi xilosa menggunakan Candida fukuyamaensis UICC Y-247 penghasil enzim xilosa reduktase yang mereduksi xilosa menjadi xilitol. Xilosa didapat dari hidrolisis hemiselulosa dalam limbah batang/malai sorgum manis CTY-33 yang telah dilakukan delignifikasi. Hasil xilosa tertinggi dengan 30 ml larutan H2SO4 0,3M dicapai pada waktu hidrolisis 35 menit yaitu 22,71% dalam hidrolisat malai sorgum manis CTY-33, dan 15,30% dalam hidrolisat batang sorgum manis CTY-33. Yield xilitol tertinggi dicapai pada fermentasi jam ke-12 yaitu 191,07 ppm dari malai, dan yield xilitol dari batang 31,48 ppm. Penambahan kosubstrat glukosa menaikkan kadar xilitol, hasil tertinggi dicapai pada jam ke-12. Penambahan kosubstrat glukosa 300 ppm pada malai menghasilkan xilitol sebesar 291,17 ppm (konversi xilosa menjadi xilitol 38,86 %). dan penambahan kosubstrat glukosa 150 ppm pada batang sebesar 173,44 ppm (konversi xilosa mnjadi xilitol 26,20.

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Producing xylitol from the straw / panicle of sweet sorghum CTY -33 wastes was done. The xylitol produced through the fermentation process of xylose using Candida fukuyamaensis UICC Y-247 which reduced xylose to xylitol using xylose reductase enzyme. The hemicellulose in the straw/panicle sweet sorghum CTY-33 wastes was hydrolized by 30 mL sulfuric acid 0,3 M after delignification. The highest xylose in the hydrolyzate of panicle during 35 minutes was 22.71 % and from straw was15.30 %. The highest xylitol yield reached in 12-hours fermentation, panicle xylitol yield was 191.07 ppm and straw xylitol yield was 31.48 ppm. When glucose added as co-substrat, the xylitol yield increased. The panicle xylitol yield became 291.170 ppm (the xylose conversion to xylitol was 38,86 %) when it added glucose 300 ppm, and the straw xylitol yield became 173.44 ppm (the xylose conversion to xylitol was 26,20 %) when it added glucose 150 ppm."

"Xilitol merupakan gula alkohol berkarbon lima, yang secara alami terdapat dalam buah-buahan dan sayuran, serta memiliki manfaat kesehatan diantaranya adalah antikariogenik dan memiliki indek glukemik rendah. Xilitol dapat diproduksi dari xilosa, baik melalui proses kimiawi ataupun dengan fermentasi. Proses fermentasi dilakukan oleh khamir penghasil enzim xilosa reduktase, Candida fukuyamaensis UICC Y-247. Xilosa dihasilkan melalui proses hidrolisis hemiselulosa yang terkandung dalam limbah lignoselulosa seperti tanaman sorgum. Dalam penelitian ini dilakukan hidrolisis terhadap tangkai dan malai limbah sorgum untuk menghasilkan xilosa yang akan digunakan sebagai bahan baku pembuatan xilitol melalui proses fermentasi dengan penambahan D(-) arabinosa sebagai kosubstrat. Sebelum hidrolisis pada sampel dilakukan proses dewax dan delignifikasi untuk menghilangkan senyawa-senyawa ekstraktif dan memecahkan lignin yang dapat menghambat proses hidrolisis ataupun fermentasi. Hidrolisis dilakukan dengan asam sulfat 0,3 molar, suhu 121°C. Berdasar hasil pengukuran didapatkan waktu optimum hidrolisis tangkai adalah 35 menit dan malai 45 menit, dengan masing-masing menghasilkan 4083,8 ppm atau 20,45% xilosa dari hidrolisat tangkai dan 4690,6 ppm atau 23,5% dari hidrolisat malai. Uji HPLC hasil fermentasi dalam penelitian ini, menunjukkan waktu optimum fermentasi adalah 12 jam. Konversi xilosa menjadi xilitol adalah 12,48%; 8,98% dan 2,66% masing-masing untuk hidrolisat malai, tangkai dan xilosa murni. Penambahan D(-) arabinosa sebagai kosubstrat menurunkan pembentukan xilitol."