On-site glucohydrolase manufacture for 2nd generation integrated to 1st generation sugarcane bioethanol production
Tuesday, April 29, 2014
Exhibit/Poster Hall, lower level (Hilton Clearwater Beach)
Josť Geraldo da Cruz Pradella, Priscila da Silva Delabona, Deise Juliana da Silva Lima and Daniel Kolling, Brazilian Laboratory of Science and Technology of Bioethanol - CTBE, Campinas, Brazil
Sugarcane 2nd generation bioethanol production integrated to a 1st generation plant is regarded as a realistic arrangement to produce this biofuel in a cost effective way. However glucohydrolases (GHs) cost production has a prominent impact on bioethanol contribution cost. The maximization of bioreactor enzyme productivity and the use of low-cost carbon source are key factors to decrease the GH contribution cost to acceptable values. In order to decrease GH cost we have studied the on-site manufacture cellulosic enzyme production with Penicillium echinulatum and Trichoderma harzianum partially catabolite de-repressed strains. We proposed the use of pretreated sugarcane bagasse and sugarcane carbohydrate (sugar juice, molasses and sucrose) as cheap culture media components allied to fed-batch submerged controlled bioreactor cultivation as main strategies to achieve this goal. It was demonstrated that steam-exploded and hydrothermal pretreated sugarcane bagasse supplemented with sucrose and soybean flour in optimized ratios lead to enzyme broth activity up to 5 FPU/mL in approximately 144h of cultivation time (enzyme productivity of 35 FPU/L h) (Scenario 1). On the other hand the use of a controlled bioreactor fed-batch culture media profile precluded an enzyme productivity up to 70 FPU/L h (Scenario 2). Preliminary economic analysis indicated a GH contribution cost of US$ 0.11 / L of produced bioethanol for the Scenario 1 and US$ 0.07 / L of produced bioethanol for the Scenario 2. Enzyme cocktail produced in optimized conditions performed bagasse enzymatic hydrolysis comparable with commercial available cocktail.