2.4.3 Analytical methods
Biomass formation has been measured at specific time points by assessing
the optical density (OD600 nm) using a spectrophotometer
(Cary50Conc, UV–vis Spectrophotometer, Australia). For the
determination of ethanol and glucose concentrations, the main culture
was harvested by centrifugation (6000×g, 12 min, 4°C), and the
supernatant was analyzed via G.C. The Glucose concentrations were
measured enzymatically using a colorimetric glucose oxidase kit (Pars
Azmun, Iran).
The concentration of ethanol was determined by using gas chromatography
GC-2550TG (Teif Gostar Faraz Company, Iran), Hydrogen gas as the carrier
gas and the injection, column and flame ionization detection (FID)
temperature was maintained at 120°C, 250°C and 250°C respectively.
Ethanol (99/9%, Merck) was used as the internal standard.