厦门大学学报（自然科学版）2011，Vol.50Issue(3)：624-630,7.
高产木糖醇酵母菌的筛选鉴定及两级法发酵特性
Isolation and Identification of a High-yield Xylitol-producing Yeast Strain and Its Two-stage Fermentation Performances
张金明 1耿安利 2姚传义 1卢英华 1李清彪3
作者信息
- 1. 厦门大学化学化工学院,福建厦门361005
- 2. 义安理工学院生命与化学技术学院,新加坡599489
- 3. 厦门大学化学生物学福建省重点实验室,福建厦门361005
- 折叠
摘要
Abstract
Xylose-utilizing yeasts isolated from soil samples in Singapore were screened for xylitol production in high xylose concentration. After several round of screening,10 strains were selected for their high tolerance to 300 g/L xylose concentration,which can convert xylose into xylirol with a yield greater than 64. 0％. Strain SB18 exhibited the maximal xylitol yield of 68. 5％ from 150 g/L xylose,and then was identified as Candida tropicalis by 18S rDNA sequencing information. Enzyme assay results indicate that in strain SB18, xylose reductase (XR) is NADPH dependent and its activity is much higher than that of xylitol dehydrogenase (XDH). A rwo-stage fermentation process was employed to investigate the cultivation condition of SB18. The results show that the best nitrogen sources are yeast extract and urea , innoculum size is 0. 5 g/L , initial xylose concentration is 250 g/L, the optimal speed switch time is 36 h with a shaking speed of 250 r/min in the first stage, and a speed of 100 r/min afterwards. Under the optimal cultivation conditions,xylitol final concentration reached 207. 65 g/L after 252 h incubation from 250 g/L,corresponding to a xylitol yield of 83. 1％ and 91. 8％ xylose-to-xylitol bioconversion efficiency. This work demonstrates that strain C. tropicalis SB1 has great potentials in industrial xylitol bioproduction in high xylose concentration.关键词
木糖醇生产/两级法发酵/热带假丝酵母/木糖还原酶/木糖醇脱氢酶Key words
xylitol production / two-stage fermentation/ Candida tropicalis / xylose reductase/ xylitol dehydrogenase分类
生物科学引用本文复制引用
张金明,耿安利,姚传义,卢英华,李清彪..高产木糖醇酵母菌的筛选鉴定及两级法发酵特性[J].厦门大学学报（自然科学版）,2011,50(3):624-630,7.
