a b s t r a c t
Eight trace elements were screened for increasing efficiency of ethanol yield from sweet
sorghum juice using the Plackett-Burman design method. MnCl2$4H2O, CoCl2$6H2O and
biotin was screened as the significant variables which have positive effects on ethanol
production from sweet sorghum juice. The values of MnCl2$4H2O, CoCl2$6H2O and biotin,
optimized by Box-Behnken design method, were 7.70 mg L1, 15.74 mg L1 and
11.97 mg L1, respectively. The experimental efficiency of ethanol yield under optimal
conditions was 89.30 0.10%, which enhances the efficiency of ethanol yield by 5.63% by
the addition of MnCl2$4H2O, CoCl2$6H2O and biotin. The results from this study have
identified optimal conditions as a foundation for pilot scale ethanol production.