Electricity generation from rapeseed straw hydrolysates using microbial fuel cells

• Rapeseed straw has undergone a process of hydrolysis.
• Experiments were conducted with various hydrolysing media.
• The study demonstrates a significant impact of enzymes on the hydrolysis yield.

Rapeseed straw is an attractive fuel material for microbial fuel cells (MFCs) due to its high content of carbohydrates (more than 60% carbohydrates). This study has demonstrated that reducing sugars can be efficiently extracted from raw rapeseed straw by combination of hydrothermal pretreatment and enzymatic hydrolysis followed by utilization as a fuel in two-chamber MFCs for electrical power generation. The most efficient method of saccharification of this lignocellulosic biomass (17%) turned out hydrothermal pretreatment followed by enzymatic hydrolysis. Electricity was produced using hydrolysate concentrations up to 150 mg/dm3. The power density reached 54 mW/m2, while CEs ranged from 60% to 10%, corresponding to the initial reducing sugar concentrations of 10–150 mg/dm3. The COD degradation rates based on charge calculation increased from 0.445 g COD/m2/d for the hydrolysate obtained with the microwave treatment to 0.602 g COD/m2/d for the most efficient combination of hydrothermal treatment followed by enzymatic hydrolysis.