Abstract: Dextran is a D-glucose polymer which is produced by
Leuconostoc mesenteroides grown in a sucrose-rich media. The
organism was obtained from the Persian Type Culture Collection
(PTCC) and was transferred in MRS broth medium at 30°C and pH
6.8 for 24 h. After preparation of inoculums, organisms were
inoculated into five liquid fermentation media containing either
molasses or cheese whey or different combinations of cheese whey
and molasses. After certain fermentation period, the produced
dextran was separated and dried. Dextran yield was calculated and
significant differences in different media were observed.
Furthermore, FT-IR analysis was performed and the results showed
that there were no significant differences in the produced dextran
structures.
Abstract: The utilization of cheese whey as a fermentation
substrate to produce bio-ethanol is an effort to supply bio-ethanol
demand as a renewable energy. Like other process systems, modeling
is also required for fermentation process design, optimization and
plant operation. This research aims to study the fermentation process
of cheese whey by applying mathematics and fundamental concept in
chemical engineering, and to investigate the characteristic of the
cheese whey fermentation process. Steady state simulation results for
inlet substrate concentration of 50, 100 and 150 g/l, and various
values of hydraulic retention time, showed that the ethanol
productivity maximum values were 0.1091, 0.3163 and 0.5639 g/l.h
respectively. Those values were achieved at hydraulic retention time
of 20 hours, which was the minimum value used in this modeling.
This showed that operating reactor at low hydraulic retention time
was favorable. Model of bio-ethanol production from cheese whey
will enhance the understanding of what really happen in the
fermentation process.
Abstract: The consumption of lactose in acid cheese whey
anaerobic fermentation process under fed-batch conditions was
studied. During fermentation for 100 hours the biogas production
(CO2 and CH4) was analyzed online. Among the standard analyses
FT-IR spectroscopy was used to follow the consumption of lactose by
bacteria. The absorption bands at 990, 894 and 787 cm-1 in the 2nd
derivative spectra were shown to be characteristic for lactose and
were used to follow the lactose conversion. It was shown that acid
cheese whey lactose was converted by bacteria in first 7 hours. In the
spectra of 17, 18 and 95 hour fermentation samples lactose was not
identified and these results correlated with the HPLC data.