Evaluation of steam‐treated giant bamboo for production of fermentable sugars

Abstract

Giant bamboo plantations are currently being established in the Southern Africa region and can be considered as potential lignocellulosic feedstock for the production of second generation bioethanol. In this study, giant bamboo internodal material was subjected to sulphur dioxide (SO(2)) impregnated steam pretreatment prior to enzymatic hydrolysis. The effect of temperature, residence time, and acidity on the overall sugar recovery and byproduct formation was studied using response surface response technology according to a central composite experimental design (CCD) at a fixed SO(2) concentration of 2.5% (w/w liquid) after impregnation. The results showed that pretreatment conditions with combined severity factor (CSF) values and enzyme dosages greater than 1.72 and 30 FPU/g water insoluble solid, respectively, were required to obtain an efficient glucan digestibility and a good overall glucose recovery. Up to 81.2% of the sugar in the raw material was recovered for a CSF of 2.25. However, considering overall sugar yield and byproducts concentration, the pretreated material obtained with a CSF of 1.62 can be considered as the most appropriate for SSF experiments using a xylose-utilizing yeast. At these conditions, it could be possible to obtain up to 247 L of ethanol per dry ton of giant bamboo considering hexose and pentose sugars fermentation. This amount could be increased up to 292 L of ethanol per dry ton of giant bamboo with the maximum sugar yield obtained (CSF = 2.25) if the microorganism possesses robust fermentative characteristics as well as a high resistance to pretreatment by-products.

Effective of Microwave-KOH Pretreatment on Enzymatic Hydrolysis of Bamboo

“…Other potential fermentation inhibitors, including furfural derived from pentoses, HMF from degradation of hexoses, and levulinic and formic acids from successive decomposition of HMF were not detected in the spent liquors. The total inhibitors were in lower concentrations in spent liquor than acid or steam pretreated spent liquors [14,15]. The concentration of acetic acid which released from acetyl groups on hemicelluloses was higher than acid pretreated spent liquor.…”

“…They may be divided up into the following broad categories: construction and reinforcing fibers; paper, textiles and board; food; combustion and other bioenergy applications [2]. Due to its advantages of fast growth, short renovation, and easy propagation, more and more attention has been paid to the applications in biobased energy field including bioethanol production [3][4][5][6].…”

Optimization of the steam explosion and enzymatic hydrolysis for sugars production from oak woods

“…In pretreatment of vineyard pruning by uncatalyzed steam explosion (Buratti et al, 2015), optimal conditions were observed at severity of 4.24, obtaining an overall sugar yield of 42.5%. In steam explosion pretreatment of giant bamboo, Garcia-Aparicio et al (2011) reported the overall sugar yield of 81.2% under optimal conditions of 2.5% sulfuric acid impregnation and severity of 4.13.…”

“…Relatively few studies have reported on the application of steam explosion with lignocellulosic feedstock, like olive tree pruning , vineyard pruning (Buratti et al, 2015), and giant bamboo (Garcia-Aparicio et al, 2011), evaluating the overall sugar yield. According to Cara et al (2008), the optimum treatment conditions of olive tree pruning for maximizing overall sugar yield (63.4%) were 1% sulfuric acid impregnation and severity of 4.53.…”

Comparison of Dilute Organic and Sulfuric Acid Pretreatment for Enzymatic Hydrolysis of Bamboo

“…Some researchers have focused on bamboo pretreatment for bioethanol production. The cellulose conversion to glucose yield of bamboo is lower than that of both wood and agricultural waste (Shimokawa et al 2009;Leenakul and Tippayawong 2010;García-Aparicio et al 2011;Li et al 2014).…”