Enzymatic hydrolysis of fast-growing poplar wood after pretreatment by steam explosion

Abstract

The aim of the present study was to investigate the effect of steam explosion pretreatment, without maintaining the heating temperature, on the yield of enzymatic hydrolysis of wood biomass. Genetically modified poplar wood was used for the investigation. The pretreatment process was conducted at temperatures of 160 °C, 175 °C, 190 °C and 205 °C. Then, the system was rapidly decompressed. The heating medium was water. The chemical composition of biomass was determined before and after the steam explosion and then enzymatic hydrolysis was performed. The results of the chemical composition analysis showed a change in the holocellulose content in the analyzed biomass (about 80% for the native sample and 72% for the biomass sample treated at 205 °C), a decrease in the hemicelluloses content from about 40% (native sample) to 16% for the sample treated at 205 °C. The results of enzymatic hydrolysis showed the lowest glucose extraction efficiency for biomass hydrolysis after the treatment at 160 °C, of only about 9% compared to the theoretical content of glucose from the cellulose contained in hydrolysed wood biomass. The highest results were obtained for the samples treated at 190 °C and 205 °C. The study also estimated the processing costs, as a function of the heating medium (steam, water) and energy source (atomic energy, hard coal, natural gas, biomass), assuming heating with electric heaters. From the economic point of view, it is advantageous to use steam heating medium, and either natural gas or biomass as an energy source.