Effect of pretreatment on saccharification of sugarcane bagasse by complex and simple enzyme mixtures

The combination of plant-expressed cellobiohydrolase and low dosages of cellulases for the hydrolysis of sugar cane bagasse

“…The intensities of ligninassociated peaks at 1728, 1630, 1599, 1512, 1464, 1416, 1329, 1244, and 835 cm -1 [23] all diminished significantly in the FTIR spectra of bagasse pretreated using acidified EC/EG (Additional file 3: Figure S3b), consistent with the removal of lignin ( Table 1). All of the lignin-associated peaks in the FTIR spectra of bagasse pretreated using BMIMCl and ball-milling were still as prominent as those in untreated bagasse (Additional file 3: Figure S3c and d).…”

“…There are few studies describing the ability of plant-expressed cellulase to hydrolyse cellulose in pretreated biomass, either alone [27][28][29][30] or in combination with sub-optimal doses of commercial cellulase mixtures [31]. The present study complements these studies and is an extension of our previous work [23], wherein we examined saccharification of bagasse pretreated using dilute NaOH, H 2 SO 4 , HCl, and acidified glycerol at the pilot scale. Herein, we have assessed plant-expressed CBH as an additive to a commercial cellulase for saccharification of these pretreated bagasse substrates and bagasse pretreated using a novel, acid-catalysed ethylene carbonate (EC)/ethylene glycol (EG) mixture, 1-butyl-3-methylimidazolium chloride (BMIMCl), and ball-milling.…”

“…These studies have clearly demonstrated that the choice of pretreatment process has a profound effect on the overall susceptibility of a given biomass to hydrolysis by commercial cellulase mixtures or mixtures of purified cellulases. In fact, we recently reported that glucan conversions obtained with mxtures of Trichoderma reesei CBH I and βG on bagasse pretreated at the pilot scale with acidified glycerol were 10 to 30% higher than those obtained with NaOH or H 2 SO 4 pretreatments [23]. However, the use of plant-expressed CBH as an additive to a commercial cellulase mixture may offer the best option to substantially reduce the costs of enzymes for lignocellulosic saccharification [24][25][26].…”

“…The compositions of untreated bagasse and bagasse pretreated in the Mackay Renewable Biocommodities Pilot Plant with dilute H 2 SO 4 steam explosion, dilute NaOH steam explosion, and glycerol/HCl steam explosion under conditions described in our previous study [23] are presented in Table 1. The compositions of untreated (depithed) and bagasse pretreated at the laboratory scale with acidified EC/EG [38], BMIMCl [39], and ballmilling are presented in the same table.…”

“…Significant enhancement in enzymatic hydrolysis of bagasse pretreated with dilute H 2 SO 4 steam explosion by adding corn stover-expressed CBH to Celluclast 1.5 L We previously demonstrated that dilute H 2 SO 4 steam exploded bagasse was relatively resistant to enzymatic hydrolysis by commercial cellulase mixtures, when compared to bagasse pretreated with dilute NaOH steam explosion or glycerol/HCl steam explosion [23]. Therefore, we assessed the ability of plant-expressed CBH to enhance the performance of a commercial cellulase mixture on this substrate.…”