Milling pretreatment of sugarcane bagasse and straw for enzymatic hydrolysis and ethanol fermentation

Abstract

The effectiveness of ball milling (BM) and wet disk milling (WDM) on treating sugarcane bagasse and straw were compared. Pretreated materials were characterized by wide angle X-ray diffraction analysis, particle-size distribution and scanning electron microscopy and the effectiveness of pretreatments was evaluated by enzymatic hydrolysis and fermentation. Glucose and xylose hydrolysis yields at optimum conditions for BM-treated bagasse and straw were 78.7% and 72.1% and 77.6% and 56.8%, respectively. Maximum glucose and xylose yields for bagasse and straw using WDM were 49.3% and 36.7% and 68.0% and 44.9%, respectively. BM improved the enzymatic hydrolysis by decreasing the crystallinity, while the defibrillation effect observed for WDM samples seems to have favored enzymatic conversion. Bagasse and straw BM hydrolysates were fermented by Saccharomyces cerevisiae strains. Ethanol yields from total fermentable sugars using a C6-fermenting strain reached 89.8% and 91.8% for bagasse and straw hydrolysates, respectively, and 82% and 78% when using a C6/C5 fermenting strain.

Thermal behavior of native, washed and steam exploded lignocellulosic biomass samples

“…Pretreatment methods can be divided into different categories. Group of physical methods contains for example hydrothermolysis, grinding, and milling [13,16,17]. Pretreatment by diluted acid, alkaline or ammonia solutions makes different chemical changes in the structure of the lignocellulosic biomass [18,19].…”

Microwave-assisted pretreatment technologies for the conversion of lignocellulosic biomass to sugars and ethanol: a review

“…The pretreatments can be classified into physical [17] or physicochemical [18], chemical [19], and biological [20] methods or combinations thereof [21][22][23]. The effectiveness of each type of pretreatment is presented in Table 2 [24][25][26][27].…”

NaOH Pretreatment of Wheat Straw at a Mesophilic Temperature: Effect on Hydrolysis and Loss of Organic Carbon

“…Enzymatic digestion experiments were carried out for 48 h at 45ºC, which is regarded as optimal [30]. The results are shown in Figs 5a-5c.…”