Increase of xylitol productivity by cell-recycle fermentation of Candida tropicalis using submerged membrane bioreactor

Candida tropicalis, an osmophilic strain isolated from honeycomb, produced xylitol at a maximal volumetric productivity of 3.5 g l −1 h −1 from an initial xylose concentration of 200 g l −1. Even at a very high xylose concentration, e.g., 350 g l −1, this strain produced xylitol at a moderate rate o...

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Veröffentlicht in:Journal of bioscience and bioengineering 2006, Vol.101 (1), p.13-18
Hauptverfasser: Kwon, Soun-Gyu, Park, Seung-Won, Oh, Deok-Kun
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Sprache:eng
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Zusammenfassung:Candida tropicalis, an osmophilic strain isolated from honeycomb, produced xylitol at a maximal volumetric productivity of 3.5 g l −1 h −1 from an initial xylose concentration of 200 g l −1. Even at a very high xylose concentration, e.g., 350 g l −1, this strain produced xylitol at a moderate rate of 2.07 g l −1 h −1. In a fed-batch fermentation of xylose and glucose, 260 g l −1 xylose was added, and the xylitol production was 234 g l −1 for 48 h, corresponding to a rate of 4.88 g l −1 h −1. To increase xylitol productivity, cells were recycled in a submerged membrane bioreactor with suction pressure and air sparging. For each recycle round in cell-recycle fermentation, the average concentration of xylitol produced, fermentation time, volumetric productivity, and product yield were 180 g l −1, 19.5 h, 8.5 g l −1 h −1, and 85%, respectively. When cell-recycle fermentation was started with the cell mass concentrated twofold after batch fermentation and performed for 10 recycle rounds, we achieved a very high productivity of 12 g l −1 h −1. The productivity and total amount of xylitol in cell-recycle fermentation were 3.4- and 11.0-fold higher than those in batch fermentation, respectively.
ISSN:1389-1723
1347-4421
DOI:10.1263/jbb.101.13