Machado Daniele Longo, Moreira Neto João, da Cruz Pradella José Geraldo, Bonomi Antonio, Rabelo Sarita Cândida, da Costa Aline Carvalho
Laboratory of Fermentative and Enzymatic Process Engineering, School of Chemical Engineering, University of Campinas, Campinas, SP, Brazil.
Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE)--CTBE/CNPEM, Campinas, SP, Brazil.
Biotechnol Appl Biochem. 2015 Sep-Oct;62(5):681-9. doi: 10.1002/bab.1307. Epub 2015 Jan 14.
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).
尽管吸附是木质纤维素材料酶水解的一个重要步骤，但文献报道了关于纤维素分解酶在不同生物质/预处理上的吸附存在有争议的结果，这使得在水解数学模型中难以描述这一现象。在这项工作中，评估了这些酶在通过水热甘蔗渣（HB）和有机溶剂甘蔗渣（OB）方法预处理的微晶纤维素和甘蔗渣上的吸附情况。结果表明，β - 葡萄糖苷酶在微晶纤维素或HB上没有显著吸附。如果搅拌速率足够高（微晶纤维素>100 rpm，HB和OB>150 rpm），将固体浓度从5%（w/v）提高到10%（w/v）对纤维素酶在不同生物质上的吸附没有影响。与木质纤维素材料（120分钟）相比，微晶纤维素的吸附平衡时间较短（10分钟）。在4℃和50℃下测定的吸附等温线表明，对于微晶纤维素，随着温度升高最大吸附容量（Emax）降低，而对于HB，温度升高Emax增加。此外，Emax随着材料中木质素含量的增加而增加。对HB酶解后剩余木质素上纤维素酶的吸附研究表明，吸附容量较低但显著（Emax = 11.92±0.76 mg/g）。
