Adsorption characteristics of cellulase and β‐glucosidase on Avicel, pretreated sugarcane bagasse, and lignin

Abstract

Although adsorption is an essential step in the enzymatic hydrolysis of lignocellulosic materials, literature reports controversial results in relation to the adsorption of the cellulolitic enzymes on different biomasses/pretreatments, which makes difficult the description of this phenomenon in hydrolysis mathematical models. In this work, the adsorption of these enzymes on Avicel and sugarcane bagasse pretreated by the hydrothermal bagasse (HB) and organosolv bagasse (OB) methods was evaluated. The results have shown no significant adsorption of β-glucosidase on Avicel or HB. Increasing solids concentration from 5% (w/v) to 10% (w/v) had no impact on the adsorption of cellulase on the different biomasses if stirring rates were high enough (>100 rpm for Avicel and >150 rpm for HB and OB). Adsorption equilibrium time was low for Avicel (10 Min) when compared with the lignocellulosic materials (120 Min). Adsorption isotherms determined at 4 and 50 °C have shown that for Avicel there was a decrease in the maximum adsorption capacity (Emax) with the temperature increase, whereas for HB increasing temperature increased Emax . Also, Emax increased with the content of lignin in the material. Adsorption studies of cellulase on lignin left after enzymatic digestion of HB show lower but significant adsorption capacity (Emax = 11.92 ± 0.76 mg/g).

Characteristics of Lignin Fractions from Dilute Acid Pretreated Switchgrass and Their Effect on Cellobiohydrolase from Trichoderma longibrachiatum

“…The adsorption data fitted well with the Langmuir isotherm. The maximum adsorptions of CBH were 7.63, 5.53, and 12.32 mg/g for the three lignin fractions, which were similar to the literature (Pareek et al, 2013;Zheng et al, 2013;Machado et al, 2015;Lu et al, 2016;Sun et al, 2016). It should be noted that the binding results could be affected by the different lignin isolation/pretreatment conditions, enzyme and test conditions (temperatures, lignin loading) used for determination.…”

The PT/S-Box of Modular Cellulase AcCel12B Plays a Key Role in the Hydrolysis of Insoluble Cellulose

“…Furthermore, the binding capacity of enzymes to RAC was 10 times higher than that to Avicel, which was similar to that reported by Hong et al [34]. The Emax of wild-type and mutant AcCel12B to Avicel and RAC were not different from those of other cellulases [34,35]. Srisodsuk et al previously noted that the linker deletions of CBH I from Trichoderma reesei did not affect the enzyme affinity on crystalline cellulose at an initial enzyme concentration of 0.2 μM (5-9% saturation), but decreased the binding capacity as the enzyme concentration approached 10 μM [6].…”

Toward a fundamental understanding of cellulase‐lignin interactions in the whole slurry enzymatic saccharification process

“…Furthermore, A. niger β‐glucosidase (pI ~ 4.0) showed minimal deactivation by isolated lignin owing to the lack of CBM . According to Machado et al ., no significant binding of A. niger β‐glucosidase on Avicel or pre‐treated bagasse was discovered. The activity of An Cel3A decreased continuously during hydrolysis of lignocellulose, which is probably due to the end‐product inhibition .…”