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The present work utilized a by-product of the starch industry in Malaysia, Sago bark waste (SB), for pretreatment and enzymatic hydrolysis. SB was subjected to two types of alkaline pretreatment to assess their effect on SB characteristic, inhibitor formation, and enzymatic hydrolysis sugar yield. Dilute sodium hydroxide (DSH) and dilute sodium bicarbonate (DSB) were used for SB pretreatment. The pretreatment was carried out in a conventional heating environment (120ºC) for 10 min before the enzymatic hydrolysis step. The results showed that the treated SB by DSB resulted in higher removal of lignin (28%) compared to DSH (25%). The TGA, XRD, and SEM analysis results revealed that both types of pretreatment have slight differences. The crystallinity index (CI) for DSH and DSB was 43.2% and 41.2%, respectively. Meanwhile, HPLC results illustrated that the only inhibitor present in the pretreatment liquor is acetic acid at 0.25 mg/ml for DBS pretreatment and 0.063 mg/ml for DSH pretreatment. 229 ± 12 mg/g of total reducing sugar was found using DSH pretreatment, which is slightly higher than that one was obtained by DSB pretreatment (219 ± 16 mg/g) after enzymatic hydrolysis step. A similar observation was found on glucose and xylose yield. These results make us interfere that the diluted level of sodium bicarbonate can lead to approximately similar results of sodium hydroxide, which offer a cheap route of the pretreatment process. [ABSTRACT FROM AUTHOR]

In this study, sugarcane bagasse (2 mm) was pretreated with 2.5% NaOH followed by steaming at 121°C for various time periods. Maximum cellulose content of 81% and delignification of 68.5% were achieved by soaking bagasse in 2.5% NaOH with a residence time of 1 h at room temperature followed by steaming at 121°C for 30 min residence time. The pretreated substrate was analyzed by SEM and FTIR to study the structural modification and functional group of the untreated and pretreated substrates. The pretreated substrate was saccharified by commercial cellulase enzyme depicting 106 µm mesh size of substrate yields maximum saccharification rate. The saccharified material was fermented by Saccharomyces cerevisiae and Pichia stipitis in mono- and co-culture modes. Maximum product yield (Yp/s) was observed by monoculture using Saccharomyces cerevisiae after 96 h of fermentation period. [ABSTRACT FROM AUTHOR]

To improve enzymatic digestibility and sugar concentration, sweet sorghum bagasse was pretreated with alkali and liquid hot water, and then subjected to fed-batch enzymatic hydrolysis. Scanning electron microscopy assay suggested that different pretreatment methods resulted in different composition and structure of residues; these changes had a significant influence on cellulose hydrolysis. Fresh substrate was pretreated and then added at different amounts during the first 48 h to yield a final dry matter content of 30% (w/v). For liquid hot water pretreatment, a maximal glucose concentration of 95.71 g/L, corresponding to 52.85% xylan removal, was obtained with the sweet sorghum bagasse pretreated at 184°C for 18 min. NaOH soaking at ambient conditions removed lignin up to 60%, and the subsequent hydrolysis with cellulase loading of less than 10 FPU/g DM, and substrate supplementation every few hours yield the high glucose and xylose concentrations of 114.89L and 29.93 g/L, respectively after 144 h. [ABSTRACT FROM PUBLISHER]

Microwave-assisted alkali pretreatment of banana pseudostem for the production of bioethanol was studied. Pretreatment of banana pseudostem was performed based on Box–Behnken experimental design. Alkali concentration, temperature, and time of pretreatment were considered as independent variables and concentration of reducing sugars was considered as response variable. Enzymatic hydrolysis of pretreated banana pseudostem was done at constant cellulase enzyme loading and yield of reducing sugars with respect to time was observed. It was found that when banana pseudostem was pretreated by 8% NaOH ratio at 90°C for 8 min, the yield of reducing sugars reached 84% by enzymatic hydrolysis of 110 h with cellulase enzyme loading of 30 FPU/g of solid. [ABSTRACT FROM PUBLISHER]