Comparison of Hydrolysis Efficiency and Enzyme Adsorption of Three Different Cellulosic Materials in the Presence of Poly(ethylene Glycol)

The addition of non-ionic surfactants has recently been confirmed to positively affect the enzymatic hydrolysis of cellulosic materials. However, the functional mechanisms of these surfactants remain unclear. This work investigated the influence of poly(ethylene glycol) (PEG) on the enzymatic hydrolysis of three cellulosic materials, namely, acid steam-exploded corn straw, pure microcrystalline cellulose (Avicel PH101), and bagasse sulfite pulp (BSP). The results showed that PEG addition led to varied effects on the enzymatic hydrolysis of different cellulosic materials. Addition of PEG was most effective on the enzymatic hydrolysis of PH101 and weakly effective on the hydrolysis of BSP. We further investigated PEG concentrations and enzymatic activities in the supernatant during hydrolysis and found that the positive effects of PEG treatment might contribute to its influence on enzyme desorption from different substrates. We also found that the efficiency of PEG depended on its capacity to bind to different substrates. PEG exhibited stronger affinity to pure cellulose than to the two other lignocellulosic substrates. These findings are helpful in further revealing the mechanism of surfactants and improving the enzymatic hydrolysis process.