Abstract:
Laboratory experiments were carried out to isolate and characterize the thermo tolerant yeast for
ethanol production from molasses and to study some environmental condition and physiological
parameters. Forty eight yeast stains were isolated from fruits (10 from banana (SB1-SB10), 7 from
mango (SM1-SM7), 7 from orange (SO1-SO7), 8 from grape (SG1-SG8), 7 from apple (SA1-SA7)
and 10 from date (SD1-SD10)), the fruits were collected from local market, Khartoum, Sudan. From
the isolated isolate, two isolates (SD6 and SG3) were selected for further tests based on thermo
tolerant, osmo tolerant and ethanol tolerant and identified by morphological and physiological
characterization. Molasses was diluted by hot water (1:1). Fermentation was carried out in Erlenmeyer
conical flasks. Fermentation media was taken into 500ml Erlenmeyer flasks and then the homogenous
suspension of yeast inoculum was inoculated into the media in an aseptic condition. To increase
ethanol yield, different amounts of nutrients were added to the molasses. The effectiveness of each
supplement was evaluated at pH 6.0and temperature of 40oC in incubation. The molasses contained
83.2% total soluble solids, 17.8% reducing sugars, 32.1% sucrose, 49.9% total sugars, 10.25% ash,
0.54% calcium, 0.28% sodium, 2.89% potassium and it had a pH value of 5.6. sugar concentrations on
ethanol production efficiency by strain SD6 and SG3 showed the best result at 40% conc.
Keywords: Thermo tolerant yeast, fermentation, molasses, ethanol production.
Description:
Laboratory experiments were carried out to isolate and characterize the thermo tolerant yeast for
ethanol production from molasses and to study some environmental condition and physiological
parameters. Forty eight yeast stains were isolated from fruits (10 from banana (SB1-SB10), 7 from
mango (SM1-SM7), 7 from orange (SO1-SO7), 8 from grape (SG1-SG8), 7 from apple (SA1-SA7)
and 10 from date (SD1-SD10)), the fruits were collected from local market, Khartoum, Sudan. From
the isolated isolate, two isolates (SD6 and SG3) were selected for further tests based on thermo
tolerant, osmo tolerant and ethanol tolerant and identified by morphological and physiological
characterization. Molasses was diluted by hot water (1:1). Fermentation was carried out in Erlenmeyer
conical flasks. Fermentation media was taken into 500ml Erlenmeyer flasks and then the homogenous
suspension of yeast inoculum was inoculated into the media in an aseptic condition. To increase
ethanol yield, different amounts of nutrients were added to the molasses. The effectiveness of each
supplement was evaluated at pH 6.0and temperature of 40oC in incubation. The molasses contained
83.2% total soluble solids, 17.8% reducing sugars, 32.1% sucrose, 49.9% total sugars, 10.25% ash,
0.54% calcium, 0.28% sodium, 2.89% potassium and it had a pH value of 5.6. sugar concentrations on
ethanol production efficiency by strain SD6 and SG3 showed the best result at 40% conc.
Keywords: Thermo tolerant yeast, fermentation, molasses, ethanol production.
