| dc.description.abstract | Potential use of low quality sweet potato (sweet potato weevil) for ethanol production by hydrolysis
and fermentation process was determined in this research. Low quality sweet potato (25% w/v) was hydrolyzed
pressure at 121C for 30 min. It was found that maximum content of reducing
sugar production was 390.99 g/L. Effects of microorganism strains (S. cerevisiae TISTR 5339, Z. mobilis TISTR 405
by 1% sulfuric acid under 15 lb/in2 and co-culture of Z. mobilis TISTR 405 and S. cerevisiae TISTR 5339) at 10%v/v inoculum,
pH 5.5 at 30C for 48 h and effects of reducing sugar content (10, 20 and 30 g/L) on efficiency of ethanol production was studied.
Results showed that S. cerevisiae TISTR 5339 was superior in terms of ethanol production compared to Z. mobilis TISTR
405 and co-culture of Z. mobilis TISTR 405 and S. cerevisiae TISTR 5339. Furthermore, kinetic value of this strain
was 26.00 g/L, 8.1 and 0.72 g/L/h for P, Y p/s and Q, respectively. The highest ethanol content (5%) was produced
when S. cerevisiae TISTR 5339 used with 10%v/v inoculum, pH 5.5 at 30ºC for 48 h. Moreover, effects of
ammonium sulphate content (0.05-0.15%), pH (4.5-5.5) and inoculum content (5-10%) on reducing sugar and
ethanol content was evaluated with response surface methodology (RSM) in Box-Benhken design. Optimum
conditions were 0.05% ammonium sulphate, pH 5.5 and 5% inoculum to show both residual reducing sugar 6.64
g/L and 9.06% ethanol production. Therefore, low quality sweet potato had a promising potential as substrate
for ethanol production for sustainably renewable energy resource. | en_US |
