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Title
Bioconversion of bamboo grass culm hydrolyzate into xylitol by yeast Candida magnoliae
Authors
MASAHIRO MIURA NAOYA MATSUMOTO KEISUKE SEINO YASUTAKA SHIMOTORI HISAYUKI NAKATANI and MASAKAZU AOYAMA
Received
February 27, 2014
Published
Volume 49 Issue 9-10 October-December
Keywords
Sasa senanensis, bamboo grass, hemicellulose hydrolyzate, xylitol, Candida magnoliae
Abstract
A sugar solution containing 32 g dm-3 of xylose was prepared from the culm of Sasa senanensis by hydrolysis with 2%
sulfuric acid with a liquid-to-solid ratio of 5 (g g-1) at 120 °C for 1 h. During the acid hydrolysis, some byproducts were
generated, such as acetic acid, furfural and low molecular weight phenols, which inhibit bioconversion of xylose to
xylitol. Except for acetic acid, these inhibitors were successfully removed from the hydrolyzate by contacting with a
steam-activated charcoal (25 g dm-3 dose) for 1 h. Bioconversion of the detoxified hydrolyzate to xylitol by the yeast
Candida magnoliae was investigated under the microaerobic conditions. The oxygen transfer rate (OTR) varied from
12.6 to 15.1 mmol-O2 dm-3 h-1. The best fermentative performance of C. magnoliae in the culm hydrolyzate of S.
senanensis (xylitol yield of 0.55−0.60 g-xylitol g-xylose-1 and volumetric productivity of 0.82 g dm-3h-1) was obtained at
the OTR ranging 14.1−15.1 mmol-O2 dm-3 h-1.
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