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Marcus A, Fox G. Fungal Biovalorization of a Brewing Industry Byproduct, Brewer's Spent Grain: A Review. Foods 2021; 10:2159. [PMID: 34574269 PMCID: PMC8465358 DOI: 10.3390/foods10092159] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/04/2021] [Accepted: 09/06/2021] [Indexed: 11/17/2022] Open
Abstract
The beer industry is a major producer of solid waste globally, primarily in the form of brewer's spent grain (BSG), which due to its low value has historically been diverted to livestock as feed or to landfills. However, its high moisture content and chemical composition positions BSG as an ideal candidate for further processing with microbial fermentation. Recent research has focused on filamentous fungi and the ability of some species therein to degrade the predominant recalcitrant cellulolignin components of BSG to produce valuable compounds. Many species have been investigated to biovalorize this waste stream, including those in the genuses Aspergillus, Penicillium, Rhyzopus, and Trichoderma, which have been used to produce a wide array of highly valuable enzymes and other functional compounds, and to increase the nutritional value of BSG as an animal feed. This review of recent developments in the application of filamentous fungi for the valorization of BSG discusses the biochemical makeup of BSG, the biological mechanisms underlying fungi's primacy to this application, and the current applications of fungi in this realm.
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Affiliation(s)
| | - Glen Fox
- Food Science and Technology Department, University of California, One Shields Ave, Davis, CA 95616, USA;
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2
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Puligundla P, Mok C. Recent advances in biotechnological valorization of brewers' spent grain. Food Sci Biotechnol 2021; 30:341-353. [PMID: 33868745 DOI: 10.1007/s10068-021-00900-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 11/28/2022] Open
Abstract
Brewers' spent grain (BSG) is the most abundant by-product of beer-brewing. BSG is rich in nutrients such as protein, fiber, minerals, and vitamins, and therefore it is conventionally used as low-cost animal feed. On the other hand, alternative utilization of BSG has gained increased attention during recent years due to technological progress in its processing and the emergence of the concept of circular economy. The valorization of BSG through biotechnological approaches is environmentally friendly and sustainable. This review was focused on recent advancements in the conversion of BSG into value-added products, including bioenergy (ethanol, butanol, hydrogen, biodiesel, and biogas), organic acids, enzymes, xylitol, oligosaccharides, and single cell protein, via biotechnological approaches. In addition, the potential applications of BSG as immobilization matrices in bioprocesses have been reviewed.
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Affiliation(s)
- Pradeep Puligundla
- Department of Food Science and Biotechnology, Gachon University, Seongnam-si, Republic of Korea
| | - Chulkyoon Mok
- Department of Food Science and Biotechnology, Gachon University, Seongnam-si, Republic of Korea
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Swart LJ, Bedzo OKK, van Rensburg E, Görgens JF. Intensification of Xylo-oligosaccharides Production by Hydrothermal Treatment of Brewer's Spent Grains: The Use of Extremely Low Acid Catalyst for Reduction of Degradation Products Associated with High Solid Loading. Appl Biochem Biotechnol 2021; 193:1979-2003. [PMID: 33534043 DOI: 10.1007/s12010-021-03525-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Accepted: 01/27/2021] [Indexed: 11/26/2022]
Abstract
Brewers' spent grains (BSG) make up to 85% of a brewery's solid waste, and is either sent to landfill or sold as cheap animal feed supplement. Xylo-oligosaccharides (XOS) obtained from BSG are antioxidants and prebiotics that can be used in food formulations as low-calorie sweeteners and texturisers. The effect of extremely low acid (ELA) catalysis in liquid hot water (LHW) hydrothermal treatment (HTT) was assessed using BSG with dry matter contents of 15% and 25%, achieved by dewatering using a screw press. Batch experiments at low acid loadings of 5, 12.5 and 20 mg/g dry mass and temperatures of 120, 150 and 170 °C significantly affected XOS yield at both levels of dry mass considered. Maximum XOS yields of 76.4% (16.6 g/l) and 65.5% (31.7 g/l) were achieved from raw BSG and screw pressed BSG respectively, both at 170 °C and using 5 mg acid/g dry mass, after 15 min and 5 min, respectively. These XOS yields were obtained with BSG containing up to 63% less water and temperatures more than 20 °C lower than that reported previously. The finding confirms that ELA dosing in LHW HTT allows lowering of the required temperature that can result in a reduction of degradation products, which is especially relevant under high solid conditions. This substantial XOS production intensification through higher solid loadings in HTT not only achieved high product yield, but also provided benefits such as increased product concentrations and decreased process heat requirements.
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Affiliation(s)
- Lukas J Swart
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Oscar K K Bedzo
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa.
| | - Eugéne van Rensburg
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
| | - Johann F Görgens
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Stellenbosch, 7602, South Africa
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Bianco A, Budroni M, Zara S, Mannazzu I, Fancello F, Zara G. The role of microorganisms on biotransformation of brewers' spent grain. Appl Microbiol Biotechnol 2020; 104:8661-8678. [PMID: 32875363 PMCID: PMC7502439 DOI: 10.1007/s00253-020-10843-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 01/11/2023]
Abstract
Brewers' spent grain (BSG) is the most abundant by-product of brewing. Due to its microbiological instability and high perishability, fresh BSG is currently disposed of as low-cost cattle feed. However, BSG is an appealing source of nutrients to obtain products with high added value through microbial-based transformation. As such, BSG could become a potential source of income for the brewery itself. While recent studies have covered the relevance of BSG chemical composition in detail, this review aims to underline the importance of microorganisms from the stabilization/contamination of fresh BSG to its biotechnological exploitation. Indeed, the evaluation of BSG-associated microorganisms, which include yeast, fungi, and bacteria, can allow their safe use and the best methods for their exploitation. This bibliographical examination is particularly focused on the role of microorganisms in BSG exploitation to (1) produce enzymes and metabolites of industrial interest, (2) supplement human and animal diets, and (3) improve soil fertility. Emerging safety issues in the use of BSG as a food and feed additive is also considered, particularly considering the presence of mycotoxins.Key points• Microorganisms are used to enhance brewers' spent grain nutritional value.• Knowledge of brewers' spent grain microbiota allows the reduction of health risks. Graphical abstract.
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Affiliation(s)
- Angela Bianco
- Department of Agricultural Science, University of Sassari, Sassari, Italy
| | - Marilena Budroni
- Department of Agricultural Science, University of Sassari, Sassari, Italy.
| | - Severino Zara
- Department of Agricultural Science, University of Sassari, Sassari, Italy
| | - Ilaria Mannazzu
- Department of Agricultural Science, University of Sassari, Sassari, Italy
| | - Francesco Fancello
- Department of Agricultural Science, University of Sassari, Sassari, Italy
| | - Giacomo Zara
- Department of Agricultural Science, University of Sassari, Sassari, Italy
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Forssell P, Treimo J, Eijsink VGH, Faulds CB, Collins S, Schols HA, Hinz SWA, Myllymäki O, Tamminen T, Zoldners J, Viljanen K, Waldron KW, Buchert J. Enzyme-Aided Fractionation of Brewer's Spent Grains in Pilot Scale. JOURNAL OF THE AMERICAN SOCIETY OF BREWING CHEMISTS 2018. [DOI: 10.1094/asbcj-2011-0408-01] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- P. Forssell
- VTT Technical Research Centre of Finland, VTT, Finland
| | - J. Treimo
- Norwegian University of Life Sciences, Department of Chemistry, Biotechnology and Food Science, Ås, Norway
| | - V. G. H. Eijsink
- Norwegian University of Life Sciences, Department of Chemistry, Biotechnology and Food Science, Ås, Norway
| | | | - S. Collins
- Institute of Food Research, Norwich, U.K
| | - H. A. Schols
- Wageningen Agricultural University, Laboratory of Food Chemistry, Wageningen, The Netherlands
| | - S. W. A. Hinz
- Wageningen Agricultural University, Laboratory of Food Chemistry, Wageningen, The Netherlands
| | - O. Myllymäki
- VTT Technical Research Centre of Finland, VTT, Finland
| | - T. Tamminen
- VTT Technical Research Centre of Finland, VTT, Finland
| | - J. Zoldners
- Latvian State Institute of Wood Chemistry, Riga, Latvia
| | - K. Viljanen
- VTT Technical Research Centre of Finland, VTT, Finland
| | | | - J. Buchert
- VTT Technical Research Centre of Finland, VTT, Finland
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Lynch KM, Steffen EJ, Arendt EK. Brewers' spent grain: a review with an emphasis on food and health. JOURNAL OF THE INSTITUTE OF BREWING 2016. [DOI: 10.1002/jib.363] [Citation(s) in RCA: 294] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Affiliation(s)
- Kieran M. Lynch
- School of Food and Nutritional Sciences; University College Cork; College Road Cork Ireland
| | - Eric J. Steffen
- School of Food and Nutritional Sciences; University College Cork; College Road Cork Ireland
| | - Elke K. Arendt
- School of Food and Nutritional Sciences; University College Cork; College Road Cork Ireland
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Pérez-Boada M, Prieto A, Prinsen P, Forquin-Gomez MP, del Río JC, Gutiérrez A, Martínez ÁT, Faulds CB. Enzymatic degradation of Elephant grass (Pennisetum purpureum) stems: influence of the pith and bark in the total hydrolysis. BIORESOURCE TECHNOLOGY 2014; 167:469-75. [PMID: 25006023 DOI: 10.1016/j.biortech.2014.06.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 06/05/2014] [Accepted: 06/07/2014] [Indexed: 05/11/2023]
Abstract
The internal pith of a high energy plant, Elephant grass (EG), was more extensively degraded (>50% dry matter) compared to the outer cortex (31%) or the whole stem (35%) by an enzyme preparation from Humicola insolens, Ultraflo. Reducing sugars and acetic acid release from the pith was also higher compared to the cortex. Supplementation of Ultraflo with a type-C feruloyl esterase increased the level of deacetylation but also led to reduced solubilisation. The addition of 20% dimethyl sulfoxide (DMSO) as a co-solvent also reduced the solubility of EG by Ultraflo, although acetic acid release was increased, complimenting previous results found on model substrates. The presence of DMSO was also shown to have a protective effect on xylanase activity but not acetyl esterase activity in Ultraflo. Xylan in the biomass was preferentially solubilised by DMSO, while Ultraflo removed more glucose than xylose.
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Affiliation(s)
- Marta Pérez-Boada
- Centro de Investigaciones Biológicas, Campus Universidad, Ramiro de Maeztu 9, 28040 Madrid, Spain.
| | - Alicia Prieto
- Centro de Investigaciones Biológicas, Campus Universidad, Ramiro de Maeztu 9, 28040 Madrid, Spain.
| | - Pepijn Prinsen
- Department of Plant Biotechnology, Instituto de Recursos Naturales y Agrobiológicas de Sevilla, CSIC, Sevilla, Spain.
| | - Marie-Pierre Forquin-Gomez
- INRA, UMR 1163 Biotechnologie des Champignons Filamenteux, 163 avenue de Luminy, 13288 Marseille cedex 09, France; Aix-Marseille Université, POLYTECH Marseille, UMR 1163 Biotechnologie des Champignons Filamenteux, 163 avenue de Luminy, 13288 Marseille cedex 09, France.
| | - José Carlos del Río
- Department of Plant Biotechnology, Instituto de Recursos Naturales y Agrobiológicas de Sevilla, CSIC, Sevilla, Spain.
| | - Ana Gutiérrez
- Department of Plant Biotechnology, Instituto de Recursos Naturales y Agrobiológicas de Sevilla, CSIC, Sevilla, Spain.
| | - Ángel T Martínez
- Centro de Investigaciones Biológicas, Campus Universidad, Ramiro de Maeztu 9, 28040 Madrid, Spain.
| | - Craig B Faulds
- Centro de Investigaciones Biológicas, Campus Universidad, Ramiro de Maeztu 9, 28040 Madrid, Spain; INRA, UMR 1163 Biotechnologie des Champignons Filamenteux, 163 avenue de Luminy, 13288 Marseille cedex 09, France; Aix-Marseille Université, POLYTECH Marseille, UMR 1163 Biotechnologie des Champignons Filamenteux, 163 avenue de Luminy, 13288 Marseille cedex 09, France.
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Milferstedt K, Godon JJ, Escudié R, Prasse S, Neyret C, Bernet N. Heterogeneity and spatial distribution of bacterial background contamination in pulp and process water of a paper mill. ACTA ACUST UNITED AC 2012; 39:1751-9. [DOI: 10.1007/s10295-012-1196-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 08/29/2012] [Indexed: 10/27/2022]
Abstract
Abstract
Identifying the source and the distribution of bacterial contaminant communities in water circuits of industrial applications is critical even when the process may not show signs of acute biofouling. The endemic contamination of facilities can cause adverse effects on process runability but may be masked by the observed daily variability. The distribution of background communities of bacterial contaminants may therefore be critical in the development of new site-specific antifouling strategies. In a paper mill as one example for a full-scale production process, bacterial contaminants in process water and pulp suspensions were mapped using molecular fingerprints at representative locations throughout the plant. These ecological data were analyzed in the process–engineering context of pulp and water flow in the facilities. Dispersal limits within the plant environment led to the presence of distinct groups of contaminant communities in the primary units of the plant, despite high flows of water and paper pulp between units. In the paper machine circuit, community profiles were more homogeneous than in the other primary units. The variability between sampled communities in each primary unit was used to identify a possible point source of microbial contamination, in this case a storage silo for reused pulp. Part of the contamination problem in the paper mill is likely related to indirect effects of microbial activity under the local conditions in the silo rather than to the direct presence of accumulated microbial biomass.
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Affiliation(s)
- K Milferstedt
- grid.419083.7 0000000103609610 INRA, UR0050, Laboratoire de Biotechnologie de l’Environnement Avenue des Etangs 11100 Narbonne France
| | - J -J Godon
- grid.419083.7 0000000103609610 INRA, UR0050, Laboratoire de Biotechnologie de l’Environnement Avenue des Etangs 11100 Narbonne France
| | - R Escudié
- grid.419083.7 0000000103609610 INRA, UR0050, Laboratoire de Biotechnologie de l’Environnement Avenue des Etangs 11100 Narbonne France
| | - S Prasse
- grid.81292.30 Centre Technique du Papier (CTP) Domaine Universitaire BP 251 38044 Grenoble Cedex 9 France
| | - C Neyret
- grid.81292.30 Centre Technique du Papier (CTP) Domaine Universitaire BP 251 38044 Grenoble Cedex 9 France
| | - N Bernet
- grid.419083.7 0000000103609610 INRA, UR0050, Laboratoire de Biotechnologie de l’Environnement Avenue des Etangs 11100 Narbonne France
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Niemi P, Faulds CB, Sibakov J, Holopainen U, Poutanen K, Buchert J. Effect of a milling pre-treatment on the enzymatic hydrolysis of carbohydrates in brewer's spent grain. BIORESOURCE TECHNOLOGY 2012; 116:155-160. [PMID: 22609670 DOI: 10.1016/j.biortech.2012.04.043] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Revised: 04/11/2012] [Accepted: 04/13/2012] [Indexed: 06/01/2023]
Abstract
Millions of tonnes of brewer's spent grain (BSG) are annually produced worldwide as a by-product of the brewing industry. BSG has the potential to be a valuable source of food, chemicals and energy if cost-efficient fractionation methods can be developed. A 2-fold improvement in carbohydrate solubilisation could be achieved through the introduction of a milling step prior to enzymatic hydrolysis. Course and fine milled fractions were characterized by particle size distribution and light microscopy. Fine milling decreased particle size down to the micron level and this in turn improved the carbohydrate solubility yield by a multi-enzyme mixture from 23% up to 45%. Carbohydrate solubilisation could be further increased through the supplementation of this enzyme preparation with additional cellulases. The physical degradation caused by the milling also liberated soluble carbohydrates without the requirement of any enzymatic treatment.
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Affiliation(s)
- Piritta Niemi
- VTT Technical Research Centre of Finland, Espoo FI-02044 VTT, Finland.
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Robertson JA, Castro-Mariñas L, Collins SRA, Faulds CB, Waldron KW. Enzymatic and chemical treatment limits on the controlled solubilization of brewers' spent grain. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2011; 59:11019-11025. [PMID: 21894957 DOI: 10.1021/jf202814j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The enzymatic hydrolysis of brewers' spent grain (BSG) has been investigated through treatment with commercial carbohydrases and proteases. Resultant residues were then chemically fractionated and delignified. Enzymatic treatments released 25-30% of the BSG mass and yielded precursors suitable for subsequent conversion to potentially value-added products. Controlled chemical fractionation selectively solubilized arabinoxylan but with no differences apparent due to prior enzyme treatment. The loss of non-polysaccharide components during alkali treatment suggests the presence of a high proportion of alkali-soluble lignin. Further delignification of the alkali-insoluble residues and further chemical fractionation released the remaining hemicellulose, to yield a residue which was >90% cellulose. Further knowledge of the properties and interaction between BSG polymers will facilitate an improved enzyme-assisted total deconstruction of BSG and hence the exploitation of its biomass.
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Affiliation(s)
- James A Robertson
- Sustainability of the Food Chain Exploitation Platform, Institute of Food Research, Norwich Research Park, Colney, Norwich NR4 7UA, UK.
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