Saccharification of water hyacinth biomass by a combination of steam explosion with enzymatic technologies for bioethanol production.

Abstract

In the present work, bioethanol was produced by sugar fermentation obtained from water hyacinth using a novelty hybrid method composed of steam explosion and enzymatic hydrolysis, using hydrolytic enzymes produced by solid-state fermentation and water hyacinth as substrate. The highest activity, 42 U for xylanase and 2 U for cellulase per gram of dry matter, respectively, was obtained. Steam explosion pretreatment was performed at 190℃ for 1, 5, and 10min, using water hyacinth sampled from the Maria Lizamba Lagoon, the Arroyo Hondo and the Amapa River. The highest amounts of reducing sugars of water hyacinth were obtained form the samples from the lagoon (5.4g/50g of dry matter) after 10min of treatment. Steamed biomass was hydrolysed using the enzymes obtained by solid-state fermentation, obtained reducing sugars (maximum 15.5g/L); the efficiency of enzymatic hydrolysis was 0.51g of reducing sugars per gram of water hyacinth. Finally, reducing sugars were fermented using Saccharomyces cerevisiae for conversion to ethanol, with the highest ethanol concentration (7.13g/L) and an ethanol yield of 0.23g/g of dry matter.