Process intensification of the ionoSolv pretreatment: effects of biomass loading, particle size and scale-up from 10\xa0mL to 1\xa0L

Clementine L Chambon,Jason P Hallett,Paul S Fennell,Pedro Verdía

doi:10.1038/s41598-021-94629-z

Clementine L Chambon, Jason P Hallett + Show 2 more

Open Access

https://doi.org/10.1038/s41598-021-94629-z

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Journal: Scientific Reports	Publication Date: Jul 28, 2021
Citations: 13	License type: open-access

Affiliation: Imperial College London

Abstract

The ionoSolv process is one of the most promising technologies for biomass pretreatment in a biorefinery context. In order to evaluate the transition of the ionoSolv pretreatment of biomass from bench-scale experiments to commercial scale, there is a need to get better insight in process intensification. In this work, the effects of biomass loading, particle size, pulp washing protocols and 100-fold scale up for the pretreatment of the grassy biomass Miscanthus giganteus with the IL triethylammonium hydrogen sulfate, [TEA][HSO4], are presented as a necessary step in that direction. At the bench scale, increasing biomass loading from 10 to 50 wt% reduced glucose yields from 68 to 23% due to re-precipitation of lignin onto the pulp surface. Omitting the pulp air-drying step maintained saccharification yields at 66% at 50 wt% loading due to reduced fiber hornification. 100-fold scale-up (from 10 mL to 1 L) improved the efficacy of ionoSolv pretreatment and increasing loadings from 10 to 20 wt% reduced lignin reprecipitation and led to higher glucose yields due to the improved heat and mass transfer caused by efficient slurry mixing in the reactor. Pretreatment of particle sizes of 1–3 mm was more effective than fine powders (0.18–0.85 mm) giving higher glucose yields due to reduced surface area available for lignin re-precipitation while reducing grinding energy needs. Stirred ionoSolv pretreatment showed great potential for industrialization and further process intensification after optimization of the pretreatment conditions (temperature, residence time, stirring speed), particle size and biomass loading. Pulp washing protocols need further improvement to reduce the incidence of lignin precipitation and the water requirements of lignin washing.

Highlights

The ionoSolv process is one of the most promising technologies for biomass pretreatment in a biorefinery context
It is worthy to note that dissolution of lignin during ionoSolv treatment introduces the possibility of lignin re-depositing onto the cellulose surface[16,17,18]
Here we have investigated the effects of a 100 fold scale up, from 10 mL to 1 L, on the ionoSolv process as an intermediate step between bench- and pilot-scales

Summary

Introduction

The ionoSolv process is one of the most promising technologies for biomass pretreatment in a biorefinery context. At the bench scale, increasing biomass loading from 10 to 50 wt% reduced glucose yields from 68 to 23% due to re-precipitation of lignin onto the pulp surface. 100-fold scale-up (from 10 mL to 1 L) improved the efficacy of ionoSolv pretreatment and increasing loadings from 10 to 20 wt% reduced lignin reprecipitation and led to higher glucose yields due to the improved heat and mass transfer caused by efficient slurry mixing in the reactor. It is worthy to note that dissolution of lignin during ionoSolv treatment introduces the possibility of lignin re-depositing onto the cellulose surface[16,17,18] This raises the need to adapt pulp washing protocols to avoid lignin re-precipitation and hornification, both of which negatively affect enzymatic hydrolysis yields

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Conclusion