Steam explosion pretreatment of softwood: the effect of the explosive decompression on enzymatic digestibility

Pielhop, Thomas; Amgarten, Janick; von Rohr, Philipp Rudolf; Studer, Michael Hans-Peter (2016). Steam explosion pretreatment of softwood: the effect of the explosive decompression on enzymatic digestibility Biotechnology for Biofuels, 9(1) BioMed Central 10.1186/s13068-016-0567-1

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Background Steam explosion pretreatment has been examined in many studies for enhancing the enzymatic digestibility of lignocellulosic biomass and is currently the most common pretreatment method in commercial biorefineries. The information available about the effect of the explosive decompression on the biochemical conversion is, however, very limited, and no studies prove that the latter is actually enhanced by the explosion. Hence, it is of great value to discern between the effect of the explosion on the one hand and the steaming on the other hand, to identify their particular influences on enzymatic digestibility. Results The effect of the explosive decompression in the steam explosion pretreatment of spruce wood chips on their enzymatic cellulose digestibility was studied systematically. The explosion had a high influence on digestibility, improving it by up to 90 % compared to a steam pretreatment without explosion. Two factors were identified to be essentially responsible for the effect of the explosion on enzymatic digestibility: pretreatment severity and pressure difference of the explosion. A higher pretreatment severity can soften up and weaken the lignocellulose structure more, so that the explosion can better break up the biomass and decrease its particle size, which enhances its digestibility. In particular, increasing the pressure difference of the explosion leads to more defibration, a smaller particle size and a better digestibility. Though differences were found in the micro- and nanostructure of exploded and non-exploded biomass, the only influence of the explosion on digestibility was found to be the macroscopic particle size reduction. Steam explosion treatments with a high severity and a high pressure difference of the explosion lead to a comparatively high cellulose digestibility of the—typically very recalcitrant—softwood biomass. Conclusions This is the first study to show that explosion can enhance the enzymatic digestibility of lignocellulosic biomass. If the enhancing effect of the explosion is thoroughly exploited, even very recalcitrant biomass like softwood can be made enzymatically digestible.

Item Type:	Journal Article (Original Article)
Division/Institute:	School of Agricultural, Forest and Food Sciences HAFL > Resource-efficient agricultural production systems School of Agricultural, Forest and Food Sciences HAFL > Agriculture
Name:	Pielhop, Thomas; Amgarten, Janick; von Rohr, Philipp Rudolf and Studer, Michael Hans-Peter0000-0003-1083-0967
Subjects:	Q Science > QD Chemistry S Agriculture > SB Plant culture S Agriculture > SD Forestry T Technology > T Technology (General)
ISSN:	1754-6834
Publisher:	BioMed Central
Language:	English
Submitter:	Simon Lutz
Date Deposited:	06 Nov 2019 09:48
Last Modified:	18 Dec 2020 13:29
Publisher DOI:	10.1186/s13068-016-0567-1
ARBOR DOI:	10.24451/arbor.8536
URI:	https://arbor.bfh.ch/id/eprint/8536