Ethanol produced by fermentation was analyzed by gas
chromatography on a Shimadzu GC-2010 equipped with an Auto-
Injector/Auto-Sampler (AOC-20i), a Stabilwax-DA column
(0.25 mm 0.25 lm 30 m) and a hydrogen FID as described previously
(Ge et al., 2011). Before injection into the GC, 50 ll of filtered
fermentation broth was diluted ten times with de-ionized
water and supplemented with 500 ll of 0.1 g/L n-butanol as an
internal standard