Fermentation kinetics were monitored by recording the
reduction of density (°Be) of the fermenting liquids at various
time intervals. Ethanol concentration was determined
by gas chromatography (GC) and high-pressure liquid
chromatography (HPLC). Ethanol was determined using a Shimadzu GC-8A Gas Liquid Chromatograph system with
a Porapac-S column and N2 as carrier gas (40ml/min). The
column temperature was 130 °C. The temperatures of the
injector and FID detector were 210 and 220 °C, respectively.
Samples of 2 l were injected directly into the column.
Butanol-1 was used as internal standard at a
concentration of 0.5% (v/v). All determinations were performed
by means of standard curves. Ethanol and residual
sugar were determined by HPLC, using a Shimadzu LC-9A
Liquid Chromatograph, consisting of a SCR-101N stainless
steel column, a LC-9A pump, a CTO-10A oven (60 °C)
and a RID-6A refractive index detector. Three times distilled
and Wltered water was used as mobile phase (0.8ml/
min) and butanol-1 was used as internal standard. Samples
of 0.5ml and 2.5ml of 1% solution of butanol-1 were
diluted to 50ml and 40 l of the latter solution were injected
into the column, after Wltration through 0.2 m micro-
Wlters. The residual sugar concentration was calculated
using standard curves and expressed as grams of residual
sugar per l. Ethanol was expressed as % (v/v). Ethanol productivity
was calculated as the grams of ethanol per litre
liquid volume produced per day (g/l/d).
Fermentation kinetics were monitored by recording thereduction of density (°Be) of the fermenting liquids at varioustime intervals. Ethanol concentration was determinedby gas chromatography (GC) and high-pressure liquidchromatography (HPLC). Ethanol was determined using a Shimadzu GC-8A Gas Liquid Chromatograph system witha Porapac-S column and N2 as carrier gas (40ml/min). Thecolumn temperature was 130 °C. The temperatures of theinjector and FID detector were 210 and 220 °C, respectively.Samples of 2 l were injected directly into the column.Butanol-1 was used as internal standard at aconcentration of 0.5% (v/v). All determinations were performedby means of standard curves. Ethanol and residualsugar were determined by HPLC, using a Shimadzu LC-9ALiquid Chromatograph, consisting of a SCR-101N stainlesssteel column, a LC-9A pump, a CTO-10A oven (60 °C)and a RID-6A refractive index detector. Three times distilledand Wltered water was used as mobile phase (0.8ml/min) and butanol-1 was used as internal standard. Samplesof 0.5ml and 2.5ml of 1% solution of butanol-1 werediluted to 50ml and 40 l of the latter solution were injectedinto the column, after Wltration through 0.2 m micro-Wlters. The residual sugar concentration was calculatedusing standard curves and expressed as grams of residualsugar per l. Ethanol was expressed as % (v/v). Ethanol productivitywas calculated as the grams of ethanol per litreliquid volume produced per day (g/l/d).
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