Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kongens Lyngby, Denmark; telephone: +45-45251429; fax: +45-45932850.
Biotechnol Bioeng. 2013 Jun;110(6):1574-82. doi: 10.1002/bit.24813. Epub 2013 Jan 17.
The newly isolated extreme thermophile Thermoanaerobacter pentosaceus was used for ethanol production from alkaline-peroxide pretreated rapeseed straw (PRS). Both the liquid and solid fractions of PRS were used. T. pentosaceus was able to metabolize the typical process inhibitors present in lignocellulosic hydrolysate, namely 5-hydroxymethyl furfural (HMF) and furfural, up to concentrations of 1 and 0.5 g L(-1) , respectively. Above these levels, xylose consumption was inhibited up to 70% (at 3.4 g-furfural L(-1) ) and 75% (at 3.4 g-HMF L(-1) ). T. pentosaceus was able to grow and produce ethanol directly from the liquid fraction of PRS, without any dilution or need for additives. However, when the hydrolysate was used undiluted the ethanol yield was only 37% compared to yield of the control, in which pure sugars in synthetic medium were used. The decrease of ethanol yield was attributed to the high amounts of salts resulting from the alkaline-peroxide pretreatment. Finally, a two-stage ethanol production process from PRS using Saccharomyces cerevisiae (utilization of hexoses in the first step) and T. pentosaceus (utilization of pentoses in the second step) was developed. Results showed that the two strains together could achieve up to 85% of the theoretical ethanol yield based on the sugar composition of the rapeseed straw, which was 14% and 50% higher compared to the yield with the yeast or the bacteria alone, respectively.
新分离的极端嗜热厌氧菌 Thermoanaerobacter pentosaceus 被用于从碱性过氧化物预处理的油菜秸秆（PRS）中生产乙醇。PRS 的液体和固体部分都被使用。T. pentosaceus 能够代谢木质纤维素水解物中存在的典型过程抑制剂，即 5-羟甲基糠醛（HMF）和糠醛，浓度分别高达 1 和 0.5 g/L。在这些水平之上，木糖的消耗被抑制了高达 70%（在 3.4 g-糠醛/L 时）和 75%（在 3.4 g-HMF/L 时）。T. pentosaceus 能够直接从 PRS 的液体部分生长和生产乙醇，无需稀释或添加任何添加剂。然而，当未稀释地使用水解物时，与使用纯糖在合成培养基中的对照相比，乙醇的产率仅为 37%。乙醇产率的降低归因于碱性过氧化物预处理产生的大量盐。最后，开发了一种使用酿酒酵母（在第一步中利用己糖）和 T. pentosaceus（在第二步中利用戊糖）从油菜秸秆进行两步乙醇生产的方法。结果表明，这两种菌株一起可以达到基于油菜秸秆糖组成的理论乙醇产率的 85%，与单独使用酵母或细菌相比，分别提高了 14%和 50%。
