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The effect of direct and counter‐current flow‐through delignification on enzymatic hydrolysis of wheat straw, and flow limits due to compressibility
Author(s) -
Pihlajaniemi Ville,
Sipponen Mika Henrikki,
Pastinen Ossi,
Nyyssölä Antti,
Laakso Simo
Publication year - 2016
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/bit.26030
Subject(s) - straw , current (fluid) , flow (mathematics) , chemistry , enzymatic hydrolysis , compressibility , hydrolysis , enzyme , pulp and paper industry , environmental science , mechanics , thermodynamics , biochemistry , physics , inorganic chemistry , engineering
This article compares the processes for wheat straw lignocellulose fractionation by percolation, counter‐current progressing batch percolation and batch reaction at low NaOH‐loadings (3–6% of DM). The flow‐through processes were found to improve delignification and subsequent enzymatic saccharification, reduce NaOH‐consumption and allow reduction of thermal severity, whereas hemicellulose dissolution was unaffected. However, contrary to previous expectations, a counter‐current process did not provide additional benefits to regular percolation. The compressibility and flow properties of a straw bed were determined and used for simulation of the packing density profile and dynamic pressure in an industrial scale column. After dissolution of 30% of the straw DM by delignification, a pressure drop above 100 kPa m −1 led to clogging of the flow due to compaction of straw. Accordingly, the maximum applicable feed pressure and volumetric straw throughput was determined as a function of column height, indicating that a 10 m column can be operated at a maximum feed pressure of 530 kPa, corresponding to an operation time of 50 min and a throughput of 163 kg m −3 h −1 . Biotechnol. Bioeng. 2016;113: 2605–2613. © 2016 Wiley Periodicals, Inc.