基因工程菌发酵秸秆水解液产生物柴油

Efficiency biodiesel production by genetic engineered strain using straw hydrolysate

目前生物柴油的价格是石化柴油的1.5倍,寻求新的廉价易得的原料降低生物柴油的成本是必然趋势。作物秸秆是一种低廉普遍的废弃物,秸秆中含有纤维素,半纤维素等成分,水解成单糖后可以作为合成生物柴油所需的糖类来源。利用前期研究构建的基因工程菌Escherichia coli pET28a(+)-PAW发酵秸秆(玉米秸秆和小麦秸秆)水解液得到乙醇,并在胞内将乙醇与外源添加的脂肪酸进行同步转化合成生物柴油的主要成分脂肪酸乙酯。HPLC分析表明玉米水解液中葡萄糖含量(10.40 g·L-1)较高,小麦水解液中木糖含量(40.56 g·L-1)较高。E.coli pET28a(+)-PAW能够有效地以小麦和玉米两种秸秆水解液作为糖类替代物发酵生产生物柴油,小麦水解液培养基中的生物柴油含量(0.30 g·L-1)高于玉米水解液培养基中的含量(0.25g·L-1),同时也高于现有报道。结果表明,以秸秆水解液作为原料,利用基因工程菌合成生物柴油是可行的,有助于降低生物柴油的原料成本。

The price of biodiesel is approximately 1.5 times higher than that of traditional diesel .It is urgent to explore cheaply available substrates to reduce the cost of biodiesel production .As one of the cheap and widespread wastes, lignocellulose contained cellulose and hemicellulose which could be hydrolyzed and used in the fermentation of biodiesel.The genetic engineered strain Escherichia coli pET28a （＋）-PAW fermented straw hydrolysates into alcohol, and further into biodiesel with fatty acids by one-step transformation in-vivo.The HPLC analysis showed that the corn straw hydrolysate had a higher glucose concentration （10.40 g·L-1 ） and the wheat straw hydrolysate had a higher xylose concentration （40.56 g·L-1 ）.When straw hydrolysates were utilized as sugar substitutes for biodiesel production by E.coli pET28a（＋）-PAW, the maximum biodiesel yield of 0.30 g· L-1 （ wheat hydrolysate ） was obtained which is higher than the yield of biodiesel 0.25 g·L-1 （corn hydrolysate） and the present reports.The straw＆amp;nbsp;hydrolysates could be utilized by genetic engineering strain as the substrates for biodiesel production , to reduce the material price of biodiesel.