<b>Ethanol production by co-culture of <i>Zymomonas mobilis</i> and <i>Pachysolen tannophilus</i> using banana peels hydrolysate as substrate

Abstract

Ethanol production by Zymomonas mobilis CCT 4494 and Pachysolen tannophilus CCT 1891 co-cultures and individual fermentation from each microorganism are evaluated with hydrolysate of banana peels. Banana peels hydrolysate was obtained by sulfuric acid pretreatment followed by enzymatic saccharification, carried out on solid fraction and used as substrate by individual and co-cultures of Z. mobilis and P. tannophilus fermentation. Effect of pH and total solids concentration of banana peels hydrolysate on ethanol production was also evaluated. Pretreatment followed by enzymatic hydrolysis was efficient and produced a medium with total sugar concentration of 72.80 g L^-1 and sugar reducing concentration of 52.90 g L^-1. Z. mobilis and P. tannophilus co-culture were more efficient than individual strains. P. tannophilus inoculated after Z. mobilis substantially improved ethanol production. The highest ethanol production using banana peels hydrolysate by microbial co-fermentation was 11.32 g L^-1, at a productivity of 0.60 g L^-1 h^-1, reaching 77.59% of the maximum theoretical yields.