Rudolf Andreas, Baudel Henrique, Zacchi Guido, Hahn-Hägerdal Bärbel, Lidén Gunnar
Department of Chemical Engineering, Lund University, Box 124, SE-221 00 Lund, Sweden.
Biotechnol Bioeng. 2008 Mar 1;99(4):783-90. doi: 10.1002/bit.21636.
Sugarcane bagasse--a residue from sugar and ethanol production from sugar cane--is a potential raw material for lignocellulosic ethanol production. This material is high in xylan content. A prerequisite for bioethanol production from bagasse is therefore that xylose is efficiently fermented to ethanol. In the current study, ethanolic fermentation of steam-pretreated sugarcane bagasse was assessed in a simultaneous saccharification and fermentation (SSF) set-up using either Saccharomyces cerevisiae TMB3400, a recombinant xylose utilizing yeast strain, or Pichia stipitis CBS6054, a naturally xylose utilizing yeast strain. Commercial cellulolytic enzymes were used and the content of water insoluble solids (WIS) was 5% or 7.5%. S. cerevisiae TMB3400 consumed all glucose and large fraction of the xylose in SSF. Almost complete xylose conversion could be achieved at 5% WIS and 32 degrees C. Fermentation did not occur with P. stipitis CBS6054 at pH 5.0. However, at pH 6.0, complete glucose conversion and high xylose conversion (>70%) was obtained. Microaeration was required for P. stipitis CBS6054. This was not necessary for S. cerevisiae TMB3400.
甘蔗渣——甘蔗制糖和乙醇生产过程中的一种残渣——是木质纤维素乙醇生产的潜在原料。这种材料木聚糖含量很高。因此，利用甘蔗渣生产生物乙醇的一个前提条件是木糖能有效地发酵成乙醇。在当前的研究中，在同步糖化发酵（SSF）装置中，使用利用木糖的重组酵母菌株酿酒酵母TMB3400或天然利用木糖的酵母菌株树干毕赤酵母CBS6054，对蒸汽预处理的甘蔗渣进行乙醇发酵评估。使用了商业纤维素酶，水不溶性固体（WIS）含量为5%或7.5%。在SSF中，酿酒酵母TMB3400消耗了所有葡萄糖和大部分木糖。在WIS为5%且温度为32℃时，几乎可以实现木糖的完全转化。在pH 5.0时，树干毕赤酵母CBS6054不发生发酵。然而，在pH 6.0时，可实现葡萄糖的完全转化和较高的木糖转化率（>70%）。树干毕赤酵母CBS6054需要微氧环境。酿酒酵母TMB3400则不需要。
