Caldicellulosiruptor bescii is the most thermophilic cellulolytic organism yet identified (T_opt 78 °C). It grows on untreated plant biomass and has an established genetic system thereby making it a promising microbial platform for lignocellulose conversion to bio-products. Here, we investigated the ability of engineered C. bescii to generate alcohols from carboxylic acids. Expression of aldehyde ferredoxin oxidoreductase (aor from Pyrococcus furiosus) and alcohol dehydrogenase (adhA from Thermoanaerobacter sp. X514) enabled C. bescii to generate ethanol from crystalline cellulose and from biomass by reducing the acetate produced by fermentation. Deletion of lactate dehydrogenase in a strain expressing the AOR–Adh pathway increased ethanol production. Engineered strains also converted exogenously supplied organic acids (isobutyrate and n-caproate) to the corresponding alcohol (isobutanol and hexanol) using both crystalline cellulose and switchgrass as sources of reductant for alcohol production. This is the first instance of an acid to alcohol conversion pathway in a cellulolytic microbe.

Caldicellulosiruptor bescii是迄今发现的最具嗜热性的纤维素分解生物（T _opt 78°C）。它生长在未经处理的植物生物量上，并具有成熟的遗传系统，从而使其成为有希望的将木质纤维素转化为生物产品的微生物平台。这里，我们调查工程化的能力C. bescii以产生选自羧酸醇。醛铁氧还蛋白氧化还原酶（表达AOR从激烈热 球菌（）和醇脱氢酶ADHA从嗜热菌。X514）启用C. bescii通过减少发酵产生的乙酸盐，从结晶纤维素和生物质中产生乙醇。表达AOR-Adh途径的菌株中乳酸脱氢酶的缺失增加了乙醇的产量。工程菌株还使用结晶纤维素和柳枝switch作为醇生产的还原剂，将外源提供的有机酸（异丁酸和正己酸）转化为相应的醇（异丁醇和己醇）。这是纤维素分解微生物中酸到醇转化途径的第一个实例。