Department of Applied Microbiology, Lund University, PO BOX 124, SE-22100 Lund, Sweden.
Microb Cell Fact. 2009 Jul 24;8:40. doi: 10.1186/1475-2859-8-40.
Sustainable and economically viable manufacturing of bioethanol from lignocellulose raw material is dependent on the availability of a robust ethanol producing microorganism, able to ferment all sugars present in the feedstock, including the pentose sugars L-arabinose and D-xylose. Saccharomyces cerevisiae is a robust ethanol producer, but needs to be engineered to achieve pentose sugar fermentation.
A new recombinant S. cerevisiae strain expressing an improved fungal pathway for the utilization of L-arabinose and D-xylose was constructed and characterized. The new strain grew aerobically on L-arabinose and D-xylose as sole carbon sources. The activities of the enzymes constituting the pentose utilization pathway(s) and product formation during anaerobic mixed sugar fermentation were characterized.
Pentose fermenting recombinant S. cerevisiae strains were obtained by the expression of a pentose utilization pathway of entirely fungal origin. During anaerobic fermentation the strain produced biomass and ethanol. L-arabitol yield was 0.48 g per gram of consumed pentose sugar, which is considerably less than previously reported for D-xylose reductase expressing strains co-fermenting L-arabinose and D-xylose, and the xylitol yield was 0.07 g per gram of consumed pentose sugar.
可持续且经济可行地从木质纤维素原料生产生物乙醇依赖于具有强大生产乙醇能力的微生物的可用性，这种微生物能够发酵原料中存在的所有糖，包括戊糖 L-阿拉伯糖和 D-木糖。酿酒酵母是一种强大的乙醇生产菌，但需要经过工程改造才能实现戊糖发酵。
构建并表征了一种新的重组酿酒酵母菌株，该菌株表达了一种改进的真菌途径，用于利用 L-阿拉伯糖和 D-木糖。新菌株能够在有氧条件下以 L-阿拉伯糖和 D-木糖作为唯一碳源生长。对构成戊糖利用途径的酶的活性以及在厌氧混合糖发酵过程中的产物形成进行了表征。
通过表达完全来源于真菌的戊糖利用途径，获得了能够发酵戊糖的重组酿酒酵母菌株。在厌氧发酵过程中，该菌株产生了生物量和乙醇。消耗每克戊糖可得到 0.48 克阿拉伯糖醇，这明显低于先前报道的同时发酵 L-阿拉伯糖和 D-木糖的 D-木糖还原酶表达菌株，消耗每克戊糖可得到 0.07 克木糖醇。
