Ethanol production from enzymatic hydrolysis of sugarcane bagasse pretreated with lime and alkaline hydrogen peroxide

In this work we evaluated ethanol production from enzymatic hydrolysis of sugarcane bagasse. Two pretreatments agents, lime and alkaline hydrogen peroxide, were compared in their performance to improve the susceptibility of bagasse to enzymatic action. Mild conditions of temperature, pressure and absence of acids were chosen to diminish costs and to avoid sugars degradation and consequent inhibitors formation. The bagasse was used as it comes from the sugar/ethanol industries, without grinding or sieving, and hydrolysis was performed with low enzymes loading (3.50 FPU g−1 dry pretreated biomass of cellulase and 1.00 CBU g−1 dry pretreated biomass of β-glucosidase). The pretreatment with alkaline hydrogen peroxide led to the higher glucose yield: 691 mg g−1 of glucose for pretreated bagasse after hydrolysis of bagasse pretreated for 1 h at 25 °C with 7.35% (v/v) of peroxide. Fermentation of the hydrolyzates from the two pretreatments were carried out and compared with fermentation of a glucose solution. Ethanol yields from the hydrolyzates were similar to that obtained by fermentation of the glucose solution. Although the preliminary results obtained in this work are promising for both pretreatments considered, reflecting their potential for application, further studies, considering higher biomass concentrations and economic aspects should be performed before extending the conclusions to an industrial process.

► Ethanol production from enzymatic hydrolysis of sugarcane bagasse.
► Comparison of two pretreatments agents, lime and alkaline hydrogen peroxide.
► Ethanol yields from the hydrolyzates were similar to fermentation of the glucose solution.
► Further studies should be performed before extending the conclusions to an industrial process.