Chacha, Nyangi; Dyrset, Nils; Mtui, Godliving; Katima, Jamidu H. Y.; Mrema, Godwill
Description:
Bioconversion of wood residues to biofuels such as ethanol is one of the feasible initiatives towards
production of renewable energy. This work compares the effectiveness of Escherichia coli KO11 and
Saccharomyces cerevisiae ATCC 96581 in fermenting Pinus patula (pine) hydrolysate pretreated by
acid-catalyzed steam explosion. The results show no significant difference in terms of the ethanol yield
when E. coli KO11 and S. cerevisiae ATCC 96581 were used. The maximum ethanol concentration
obtained in test tubes fermentation were 18.30 and 19.41 g/l for E. coli KO11 and S. cerevisiae ATCC
96581, respectively, from samples pretreated at 225°C/5 min. The ethanol yields obtained using
bioreactors for samples pretreated at 225°C, 0.5% SO2, and 5 min, were 21.30 and 19.63 g/l for E. coli
and S. cerevisiae, respectively. Overall, ethanol yields were higher in bioreactors than in test tubes for
both strains. In comparison, S. cerevisiae consumed the substrate faster than E. coli, thus making S.
cerevisiae the most preferred strain in fermentation of hydrolysates from steam pretreated P. patula.