The influence of lignin on steam pretreatment and mechanical pulping of poplar to achieve high sugar recovery and ease of enzymatic hydrolysis.

Richard P Chandra, QiuLu Chu, Jinguang Hu, Na Zhong, Mandy Lin, Jin-Suk Lee, Jack Saddler

Index: Bioresour. Technol. 199 , 135-41, (2015)

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Abstract

With the goal of enhancing overall carbohydrate recovery and reducing enzyme loading refiner mechanical pulping and steam pretreatment (210°C, 5 min) were used to pretreat poplar wood chips. Neutral sulphonation post-treatment indicated that, although the lignin present in the steam pretreated substrate was less reactive, the cellulose-rich, water insoluble component was more accessible to cellulases and Simons stain. This was likely due to lignin relocation as the relative surface lignin measured by X-ray photoelectron spectroscopy increased from 0.4 to 0.8. The integration of sulphite directly into steam pretreatment resulted in the solubilisation of 60% of the lignin while more than 80% of the carbohydrate present in the original substrate was recovered in the water insoluble fraction after Na2CO3 addition. More than 80% of the sugars present in the original cellulose and xylan could be recovered after 48 h using an enzyme loading of 20 mg protein/g cellulose at a 10% substrate concentration.Copyright © 2015 Elsevier Ltd. All rights reserved.