Journal: Applied and Environmental Microbiology
Article Title: Synthesis of Heterologous Mevalonic Acid Pathway Enzymes in Clostridium ljungdahlii for the Conversion of Fructose and of Syngas to Mevalonate and Isoprene
Figure Lengend Snippet: GC-MS detection of isoprene using SPME of culture headspace for C. ljungdahlii cultivated on syngas. C. ljungdahlii WT and the pJF100 Fdii N-terminally His-tagged IspS transformant were cultivated for 20 h at 30°C on MES-0F plus syngas ( Table 2 and File S2). After starting at an OD 600 of 0.5, the final OD 600 values were 1.034 and 0.888, respectively. The headspace was first sampled for GC determination of CO and CO 2 (see Table 3 ) and then separately sampled using SPME for isoprene content (see Table 2 ). (A) Gas chromatogram of the SPME-desorbed material with MS total ion detection for the WT (black) and the transformant (blue). The isoprene retention time (RT) is 10.25 min as determined by an isoprene standard (not shown). (B) Gas chromatogram with MS detection of isoprene using extracted ion mode (average m/z of 67 from 66.70 to 67.70) and splitless injection for the WT (black) and transformant (blue). (C) MS total ion mass spectrum at 10.251 to 10.26 min retention time for the transformant compared to the total ion mass spectrum (D) of an isoprene standard.
Article Snippet: They were injected in splitless mode into the injection port (front inlet temperature, 110°C) of a 7890A gas chromatograph (Agilent) coupled to a 7975C mass spectrometer (Agilent, operating in electron ionization mode).
Techniques: Gas Chromatography-Mass Spectrometry, Solid-phase Microextraction, Mass Spectrometry, Injection