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Xylitol is a sugar-alcohol with important technological properties, such as anticariogenicity, low caloric value, and negative dissolution heat. It can be used successfully in food formulations and pharmaceutical industries. Its production is therefore in great demand. Biotechnological xylitol production has several economic advantages in comparison with the conventional process based on the chemical reduction of xylose. The efficiency and the productivity of this fermentation chiefly depends on the microorganism and the process conditions employed. In this article a simple continuous culture with cell recycling was evaluated to enhance the capability of Candida guilliermondii FTI 20037 to produce xylitol. The fermentation was initiated batchwise by directly inoculating the grown seed culture in a 2-L bench-scale fermentor. Continuous feeding was begun at a dilution rate (D) of 0.060/h after the xylose concentration had completely consumed and the cell concentration was about 4.0 g/L. At a dilution rate of 0.060/h the xylitol concentration was about 15 g/L and increased by about 35%, whereas the dilution rate decreased by about 58%. Furthermore, the volumetric productivity, Qp, markedly depended on the dilution rate, diminishing by about 37% as D was changed from 0.060 to 0.025/h. These preliminary results show us that continuous fermentation with cell recycling is a good way to study the xylitol production by xylose-fermenting yeasts.

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<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>rras, tuvieron contacto directo con las bellas orquídeas que engalanaban las extensas selvas. Muestra de esto es la representación de algunas especies del género </span><span>Oncidium </span><span>en las denominadas “águilas de oro”. Probablemente hicieron uso de algu- nas de ellas en el campo de la medicina. </span></p></div></div></div>

Ausgehend von 2,3-Butandiol konnen eine ganze Reihe von chemischen Grundstoffen hergestellt werden. AuBerdem wird Butandiol auch direkt als Extraktionsmittel und Losungsmittel eingesetzt. 2,3-Butandiol ist mikrobiologisch abbaubar. Diese Bioabbaubarkeit ermoglicht es, 2,3-Butandiol als umweltfreundliches Losungs-oder Vernetzungsmittel bei der Herstellung von Farbstoffen oder Polymeren einzusetzen.