H2 and CO2 concentration in the headspace of bottles were
measured with a gas chromatograph SRI Instrument model
8610Cequippedwith1.8mlongand3.18mmdiameter stainless
steel column packed with molecular sieve 13, 1.8mlong and
3.18mmdiameter stainless steel columnpacked with silica gel,
a thermal conductivity detector (TCD) and an heliumionization
detector (HID). The carrier gas was helium. Total gas produced
by the bacteria was corrected for solubilised gas according to
Henry's law [22] and the bicarbonate equilibriumfor CO2.