Alkaline extraction of polyphenols for valorization of industrial spruce bark

Marc Borrega; Anna Kalliola; Marjo Määttänen; Anna S. Borisova; Atte Mikkelson; Tarja Tamminen

doi:10.1016/j.biteb.2022.101129

Alkaline extraction of polyphenols for valorization of industrial spruce bark

Marc Borrega^*, Anna Kalliola, Marjo Määttänen, Anna S. Borisova, Atte Mikkelson, Tarja Tamminen

^*Corresponding author for this work

Research output: Contribution to journal › Article › Scientific › peer-review

14 Citations (Scopus)

Abstract

Industrial spruce bark is an abundant side-stream from forest industries that contains tannins and other phenolic compounds that can be exploited in a variety of applications. In this study, alkaline extractions of spruce bark conducted under a wide range of process conditions showed that 20–27 % of the bark could be extracted as polyphenols, mainly tannins and some lignin. The polyphenols in alkaline extracts from two selected scale-up extractions, conducted at 100 °C with 15 % NaOH and at 160 °C with 24 % NaOH, were then recovered by acidic precipitation and tested as surfactants. Despite their different composition, the polyphenol-rich precipitates showed similar surface activity than a commercial biosurfactant, and were also soluble under neutral conditions. Moreover, sugar yields above 80 % could be obtained by enzymatic saccharification of the extracted bark residues. These results demonstrated that alkaline extraction is a promising technology for valorization of industrial bark side-streams.

Original language	English
Article number	101129
Number of pages	8
Journal	Bioresource Technology Reports
Volume	19
Early online date	23 Jun 2022
DOIs	https://doi.org/10.1016/j.biteb.2022.101129
Publication status	Published - Sept 2022
MoE publication type	A1 Journal article-refereed

Funding

Funding from Business Finland for the project OptiBark - Biobased materials and chemicals from industrial bark and willow by optimized processes (grant number 6495/31/2019 ), and co-financed by Sweden's Innovation Agency Vinnova , is gratefully acknowledged. Rauni Seppänen (Project Manager) from Holmen is warmly thanked for providing the softwood bark and for valuable discussions on the results.

Keywords

Alkaline extraction
Bark
Polyphenols
Saccharification
Surface tension
Tannins

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10.1016/j.biteb.2022.101129Licence: CC BY

Cite this

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title = "Alkaline extraction of polyphenols for valorization of industrial spruce bark",

abstract = "Industrial spruce bark is an abundant side-stream from forest industries that contains tannins and other phenolic compounds that can be exploited in a variety of applications. In this study, alkaline extractions of spruce bark conducted under a wide range of process conditions showed that 20–27 % of the bark could be extracted as polyphenols, mainly tannins and some lignin. The polyphenols in alkaline extracts from two selected scale-up extractions, conducted at 100 °C with 15 % NaOH and at 160 °C with 24 % NaOH, were then recovered by acidic precipitation and tested as surfactants. Despite their different composition, the polyphenol-rich precipitates showed similar surface activity than a commercial biosurfactant, and were also soluble under neutral conditions. Moreover, sugar yields above 80 % could be obtained by enzymatic saccharification of the extracted bark residues. These results demonstrated that alkaline extraction is a promising technology for valorization of industrial bark side-streams.",

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AU - Kalliola, Anna

AU - Määttänen, Marjo

AU - Borisova, Anna S.

AU - Mikkelson, Atte

AU - Tamminen, Tarja

PY - 2022/9

Y1 - 2022/9

N2 - Industrial spruce bark is an abundant side-stream from forest industries that contains tannins and other phenolic compounds that can be exploited in a variety of applications. In this study, alkaline extractions of spruce bark conducted under a wide range of process conditions showed that 20–27 % of the bark could be extracted as polyphenols, mainly tannins and some lignin. The polyphenols in alkaline extracts from two selected scale-up extractions, conducted at 100 °C with 15 % NaOH and at 160 °C with 24 % NaOH, were then recovered by acidic precipitation and tested as surfactants. Despite their different composition, the polyphenol-rich precipitates showed similar surface activity than a commercial biosurfactant, and were also soluble under neutral conditions. Moreover, sugar yields above 80 % could be obtained by enzymatic saccharification of the extracted bark residues. These results demonstrated that alkaline extraction is a promising technology for valorization of industrial bark side-streams.

AB - Industrial spruce bark is an abundant side-stream from forest industries that contains tannins and other phenolic compounds that can be exploited in a variety of applications. In this study, alkaline extractions of spruce bark conducted under a wide range of process conditions showed that 20–27 % of the bark could be extracted as polyphenols, mainly tannins and some lignin. The polyphenols in alkaline extracts from two selected scale-up extractions, conducted at 100 °C with 15 % NaOH and at 160 °C with 24 % NaOH, were then recovered by acidic precipitation and tested as surfactants. Despite their different composition, the polyphenol-rich precipitates showed similar surface activity than a commercial biosurfactant, and were also soluble under neutral conditions. Moreover, sugar yields above 80 % could be obtained by enzymatic saccharification of the extracted bark residues. These results demonstrated that alkaline extraction is a promising technology for valorization of industrial bark side-streams.

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KW - Saccharification

KW - Surface tension

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Alkaline extraction of polyphenols for valorization of industrial spruce bark

Abstract

Funding

Keywords

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OptiBark: Biobased materials and chemicals from industrial bark and willow by optimized processes

Cite this

Alkaline extraction of polyphenols for valorization of industrial spruce bark

Abstract

Funding

Keywords

Access to Document

Other files and links

Fingerprint

Projects

OptiBark: Biobased materials and chemicals from industrial bark and willow by optimized processes

Cite this