Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • harvard-cite-them-right
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Brewing Process Development by Integration of Edible Filamentous Fungi to Upgrade the Quality of Brewer’s Spent Grain (BSG)
University of Borås, Faculty of Textiles, Engineering and Business.ORCID iD: 0000-0002-1214-8614
University of Borås, Faculty of Textiles, Engineering and Business.
University of Borås, Faculty of Textiles, Engineering and Business.ORCID iD: 0000-0003-4887-2433
2021 (English)In: BioResources, ISSN 1930-2126, Vol. 16, no 1, p. 1686-1701Article in journal (Refereed) Published
Sustainable development
According to the author(s), the content of this publication falls within the area of sustainable development.
Abstract [en]

Brewer’s spent grain (BSG) is the main solid by-product of the brewing sector. High moisture and nutrient-rich content render BSG easily perishable, leading to waste generation and environmental impacts. BSG has narrow applications in both feed and food sectors due to its composition including high fiber and low protein. Therefore, a processing strategy leading to the nutritional valorization of BSG could widen its applications. In this study, submerged cultivation of edible filamentous fungi (Aspergillus oryzae, Neurospora intermedia, and Rhizopus delemar) was introduced as a strategy to enhance the protein content of BSG. The growth of all strains in BSG increased the protein content of the fermented BSG. The highest increase of protein content (from 22.6% to 34.6%), was obtained by cultivation using A. oryzae and medium supplementation. The protein content increase was followed by a decrease in the content of polysaccharides (up to ca. 50%), namely starch, glucan, xylan, and arabinan. The addition of cellulase resulted in enhanced ethanol production from BSG but led to lower concentration of recovered solids. In conclusion, simple processing of BSG using edible filamentous fungi can lead to quality improvement of BSG, providing potential economic and environmental benefits to the brewing sector.

Place, publisher, year, edition, pages
2021. Vol. 16, no 1, p. 1686-1701
Keywords [en]
Edible filamentous fungi, Brewer’s spent grain, Protein recovery, Submerged cultivation
National Category
Industrial Biotechnology
Research subject
Resource Recovery
Identifiers
URN: urn:nbn:se:hb:diva-25125DOI: 10.15376/biores.16.1.1686-1701ISI: 000634696900046OAI: oai:DiVA.org:hb-25125DiVA, id: diva2:1533834
Funder
Swedish Agency for Economic and Regional GrowthAvailable from: 2021-03-03 Created: 2021-03-03 Last updated: 2023-05-04Bibliographically approved
In thesis
1. Unlocking the Potential of Brewer’s Spent Grain: Sustainable Biorefinery Approach and Value-Added Product Generation
Open this publication in new window or tab >>Unlocking the Potential of Brewer’s Spent Grain: Sustainable Biorefinery Approach and Value-Added Product Generation
2023 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Brewer’s spent grain (BSG) constitutes 85% of brewing byproducts and 30% of initial malt. In 2021, BSG production reached approximately 37.2 million tons. Owing to its high moisture and nutritional content, BSG is prone to biological deterioration, causing environmental issues when discarded as waste. It has limited application as low-quality animal feed owing to its high fiber and low protein content, making landfilling the primary disposal method. However, BSG's abundance of starch, cellulose, hemicellulose, lignin, and protein make it ideal for value-added product generation in a biorefinery. The aim of this research was to investigate BSG fractionation and identify valuable products from each fraction, ultimately establishing a BSG-based biorefinery for sustainable valorization. 

Fungal cultivation, anaerobic digestion, hydrothermal, and organosolv pretreatments were employed to establish a BSG-based biorefinery. Edible filamentous fungi (Aspergillus oryzae, Neurospora intermedia, and Rhizopus delemar) were cultivated on crude BSG to produce food and feed-grade biomass. Fungal growth increased the protein content of the BSG by up to 47%. However, entangled solids with fungal filaments negatively affected product digestibility, limiting its incorporation in food and feed. This problem was resolved by recovering a solid-free, starch- and protein-rich stream from BSG via hydrothermal pretreatment. 

Hydrothermal pretreatment effectively separated BSG's starch and protein components, with solubilizations reaching 82% and 48% of the initial content, respectively. Fungal assimilation of the liquid stream produced pure, high-protein biomass and high ethanol yield. However, most of the BSG cellulose and lignin remained in the solid fraction. Organosolv pretreatment was applied to further separate BSG polymers into valorizable fractions efficiently, yielding a cellulose-rich solid stream, polysaccharide-rich organosolv liquor, and high-purity lignin (~95%). This pure lignin product can enhance the biorefinery’s economy and be sold or converted into platform chemicals. 

Direct fungal cultivation on cellulose-rich pulp and liquor fractions from organosolv revealed that the liquor fraction was suitable for producing pure, high-protein fungal biomass, while the pulp fraction required further processing. Moreover, anaerobic digestion was employed to produce a diverse array of products improving the product flexibility of the biorefinery. Organosolv liquor produced biohydrogen and volatile fatty acids (VFAs) without methanogen inhibition, while BSG and BSG organosolv solid fractions generated biogas. Inhibiting methanogens shifted the BSG process towards VFAs production, while organosolv solid fractions showed limited potential for VFAs generation. 

These results illustrate that BSG can serve as the foundation for a multi-product biorefinery that generates food-grade fungal biomass and valuable co-products, including high-purity lignin, bioethanol, biogas, biohydrogen, and VFAs. This flexibility allows the biorefinery to adapt to market changes and ensure its economic viability. 

Place, publisher, year, edition, pages
Borås: Högskolan i Borås, 2023
Series
Skrifter från Högskolan i Borås, ISSN 0280-381X ; 136
Keywords
Brewer's spent grain, Hydrothermal pretreatment, Organosolv pretreatment, Edible filamentous fungi, Anaerobic digestion, Biorefinery
National Category
Biochemistry and Molecular Biology
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-29573 (URN)978-91-89271-90-6 (ISBN)978-91-89271-91-3 (ISBN)
Public defence
2023-06-02, C203, Allégatan 1, Borås, 10:00 (English)
Opponent
Supervisors
Available from: 2023-05-04 Created: 2023-03-28 Last updated: 2023-08-02Bibliographically approved

Open Access in DiVA

fulltext(892 kB)80 downloads
File information
File name FULLTEXT01.pdfFile size 892 kBChecksum SHA-512
c7a9bf658e9a0cb971d4c4baa2cf04bc7122b8aaea311dc5dbd404f78fd66ce9be127ddd4901f44e6b96104fa006075e204366d15cc6ebb410701855c522420c
Type fulltextMimetype application/pdf

Other links

Publisher's full texthttps://ojs.cnr.ncsu.edu/index.php/BioRes/article/view/BioRes_16_1_1686_Parchami_Brewing_Process_Development_Integration_Grain

Authority records

Parchami, MohsenFerreira, JorgeTaherzadeh, Mohammad J

Search in DiVA

By author/editor
Parchami, MohsenFerreira, JorgeTaherzadeh, Mohammad J
By organisation
Faculty of Textiles, Engineering and Business
Industrial Biotechnology

Search outside of DiVA

GoogleGoogle Scholar
Total: 80 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 548 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • harvard-cite-them-right
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf