Derivatization-free gel permeation chromatography elucidates enzymatic cellulose hydrolysis

Abstract

BackgroundThe analysis of cellulose molecular weight distributions by gel permeation chromatography (GPC) is a powerful tool to obtain detailed information on enzymatic cellulose hydrolysis, supporting the development of economically viable biorefinery processes. Unfortunately, due to work and time consuming sample preparation, the measurement of cellulose molecular weight distributions has a limited applicability until now.ResultsIn this work we present a new method to analyze cellulose molecular weight distributions that does not require any prior cellulose swelling, activation, or derivatization. The cellulose samples were directly dissolved in dimethylformamide (DMF) containing 10-20% (v/v) 1-ethyl-3-methylimidazolium acetate (EMIM Ac) for 60 minutes, thereby reducing the sample preparation time from several days to a few hours. The samples were filtrated 0.2 μm to avoid column blocking, separated at 0.5 mL/min using hydrophilic separation media and were detected using differential refractive index/multi angle laser light scattering (dRI/MALLS). The applicability of this method was evaluated for the three cellulose types Avicel, α-cellulose and Sigmacell. Afterwards, this method was used to measure the changes in molecular weight distributions during the enzymatic hydrolysis of the different untreated and ionic liquid pretreated cellulose substrates. The molecular weight distributions showed a stronger shift to smaller molecular weights during enzymatic hydrolysis using a commercial cellulase preparation for cellulose with lower crystallinity. This was even more pronounced for ionic liquid-pretreated cellulose.ConclusionsIn conclusion, this strongly simplified GPC method for cellulose molecular weight distribution allowed for the first time to demonstrate the influence of cellulose properties and pretreatment on the mode of enzymatic hydrolysis.

Interactions between callose and cellulose revealed through the analysis of biopolymer mixtures

“…Callose commercial analogue, the (1–3)-β-D-glucan Pachyman and aniline blue fluorochrome were obtained from Biosupplies Australia ( www.biosupplies.com.au ). The molecular weight of Avicel PH-101 is 28 400 g mol −1 58 whereas of Pachyman it is as 168,000 g mol -1 59 . The molecular weight distribution of Avicel PH-101, as well as polydispersity and crystallinity index were reported elsewhere 60 , 61 .…”

“…The molecular weight of Avicel PH-101 is 28 400 g mol −1 58 whereas of Pachyman it is as 168,000 g mol -1 59 . The molecular weight distribution of Avicel PH-101, as well as polydispersity and crystallinity index were reported elsewhere 60 , 61 . Molecular weight and other properties (such as polydispersity, flexibility and conformation of polymers) were also reported elsewhere for Pachyman 62 .…”

Fouling Analysis and the Recovery of Phytosterols from Orange Juice Using Regenerated Cellulose Ultrafiltration Membranes

“…This created distinctive membrane surface properties (Guo 2018). Studies on the membrane polymer composition have been carried out by using gel permeation chromatography (GPC) to determine polymer molecular weight distribution (Engel et al 2012). Figure 8 shows the chromatogram of GPC analyses for the RCA 10-kDa membrane.…”

Enzymatic hydrolysis of lignocellulosic polysaccharides in the presence of ionic liquids

“…IL pretreatment of pure cellulosic substrates (especially MCC) has thereafter been widely studied. [70][71][72][73][74] MCC serves well as a model substance for studying the effects of IL pretreatment, but cannot be con-sidered an industrially relevant substrate for glucose production. IL pretreatments for the hydrolysis of industrially relevant substrates, such as wheat, 75,76 rice straw, [77][78][79][80] wood, [81][82][83][84][85] corn stover, [86][87][88] switchgrass, 31,81,82,89 bagasse, 47,[90][91][92] cotton waste textiles, 93 fibre sludge 94 and other lignocellulosic feedstocks, have been extensively studied.…”