Pulsed fed-batch process with low-cost carbon source to increase Penicillium echinulatum S1M29 cellulase and hemicellulase production in submerged bioreactor

Penicillium echinulatum S1M29 is a promising cellulolytic filamentous fungi strain partially carbon catabolite de-repressed obtained by hydrogen peroxide mutation. Glycoside hydrolase (GH) enzymes must be manufactured at low price in order to be used in cost effective 2^nd generation biofuels and chemicals production. Preliminary economic analysis indicated that bioreactor investment and carbon source are main drivers in GH composition cost formation. We have been studied sugarcane bagasse as a low-cost carbon-inductor source and concluded that hydrothermal pretreated bagasse (190^oC, 10 minutes) followed by NaOH delignification (BHD) was the best substituted of high-cost pure cellulose. Afterwards it was determined in batch assays, which were the ranges of BHD concentrations (non-limited and non-repressor) in order to attain the highest productivity and GH yield for P. echinulatum S1M29 strain. The observed kinetic data (BHD consumption, cell mass and enzyme production) allowed us to propose a BHD pulsed fed-batch process guided by agitation/aeration fluctuation in the bioreactor. The BHD pulsed fed-batch protocol allowed to produce a cellulolytic-hemicellulolytic enzymatic cocktail in 192 h of fermentation time with following characteristics: FPase 10 FPU/mL, xylanase 910 IU/mL; protein concentration 5 mg/mL. This was the highest process production performance reported to this strain to date. The produced enzyme complex was used to perform enzymatic hydrolysis of 15 to 20% w/v of acid pretreated sugarcane bagasse and the results will be reported.