The Use of Giant Miscanthus (Miscanthus × Giganteus) in 2G Bioethanol Production

Abstract

The study aimed to obtain bioethanol from biomass using chemical treatment and enzymatic hydrolysis. Different concentrations of sodium hydroxide (5 and 10%) were used for the delignification process, and enzymatic hydrolysis was carried out using three commercial cellulolytic preparations (Cellic® CTec2, cellulase from Trichoderma reesei and cellulase from Aspergillus species). The final step involved an alcoholic fermentation process using Saccharomyces cerevisiae TYPE II yeast. After enzymatic hydrolysis, the content of reducing sugars was determined in the samples, and the fermentation yield was controlled by determining the ethanol content by pycnometry. Using chemical pretreatment increased the yield of the whole process by at least 50%. The content of reducing sugars after hydrolysis depended on the type of enzyme preparation used for hydrolysis and the use of NaOH in pretreatment. The highest reducing sugars content (45.8 g/dm3) was achieved in a sample of material purified with 5% NaOH, and enzymatic hydrolysis was carried out using Cellic® CTec2. It means the efficiency of the enzymatic hydrolysis process equals 94.69%. The concentration of bioethanol after alcoholic fermentation in this sample was 0.509 g/l.