The effect of 1-ethyl-3-methylimidazolium acetate on the enzymatic degradation of cellulose

• Cellulase action in concentrated ionic liquid.
• Novel approach to address cellulase activity directly using cellulose.
• Distinct degradation pattern for cellulose I and II.

The effect of cellulose pre-treatment with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) on the enzymatic hydrolysis with a cellulase from Trichoderma reesei was studied. Enzymatic assays were performed with three different pulps – cotton linters, sulfite dissolving pulp, and eucalyptus Kraft pulp. The reaction kinetics were determined by two different methods: (i) the classical test based on the measurement of released reducing sugars from a water soluble cellulosic substrate (carboxy methyl cellulose (CMC)), and (ii) a novel approach where the enzymatic activity is determined as function of the molecular weight decrease of underivatized cellulose. Furthermore the impact of the pure ionic liquid on the stability of the enzyme was investigated. We found that enzymatic degradation of cellulose I followed a completely different degradation pattern in the molecular weight distribution and sugar solubilzation compared to the corresponding regenerated cellulose II.

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