重组大肠杆菌HW2利用甘油产氢气的研究

Hydrogen Production from Glycerol Using a Genetically Engineered Escherichia Coli HW2 Strain

从前期得到的一株能在厌氧下高效利用甘油的大肠杆菌突变株HW2出发,通过基因工程改造,提高菌株利用甘油产氢气的能力。首先敲除乳酸脱氢酶基因ldh A和丙酮醛合成酶基因mgs A,得到工程菌株HW2Δldh AΔmgs A。将该菌株在甘油培养基中厌氧培养,结果表明敲除这两基因不影响菌株的生长。培养48 h后,菌株HW2Δldh AΔmgs A的氢气产量为(410.6±33.0)μmol?mg protein-1,是出发菌株HW2的1.6倍。接着在该菌株中过表达经密码子优化的弗氏柠檬杆菌二羟基丙酮激酶来进一步提高氢气的产量。最终获得氢气高产菌株HW2Δldh AΔmgs A p CA24N-dha KL,经过厌氧培养48 h后,氢气产量为(571.5±30.3)μmol?mg protein-1,是出发菌株HW2的2.1倍。

An engineered E. coli strain was constructed to enhance the hydrogen production of Escherichia coli HW2 that can dissimilate glycerol effectively under anaerobic condition. The ldh A and mgs A genes were first knocked out to construct HW2 Δldh AΔmgs A. This new strain grew similarly as HW2 in glycerol medium and produced（410.6±33.0） μmol？mg protein-1 of hydrogen in 48 h, which was 1.6-fold higher than that of HW2. The dha KL gene coded dihydroxyacetone kinase from Citrobacter freundii was optimized and overexpressed in HW2 Δldh AΔmgs A. The strain HW2 Δldh AΔmgs A p CA24N-dha KL can produce（571.5±30.3） μmol？mg protein-1 of hydrogen in 48 h, which is 2.1-fold higher than that of the original strain HW2.