{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,19]],"date-time":"2026-02-19T00:51:41Z","timestamp":1771462301398,"version":"3.50.1"},"reference-count":44,"publisher":"MDPI AG","issue":"7","license":[{"start":{"date-parts":[[2021,4,3]],"date-time":"2021-04-03T00:00:00Z","timestamp":1617408000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["PTDC\/BTA-BTA\/31746\/2017; SFRH\/BD\/136300\/2018; UID\/Multi\/04378\/2019; UID\/Multi\/50016\/2019"],"award-info":[{"award-number":["PTDC\/BTA-BTA\/31746\/2017; SFRH\/BD\/136300\/2018; UID\/Multi\/04378\/2019; UID\/Multi\/50016\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Applied Sciences"],"abstract":"<jats:p>This work is focused on the valorization of brewer\u2019s spent grains (BSG) into volatile fatty acids (VFA) through acidogenic fermentation. VFAs are building blocks for several applications, such as bioplastics\u2019 production. Using acid hydrolysis as pre-treatment, several batch assays were performed and the impact of organic load (OL) and pH on VFA production from BSG hydrolysate was assessed. Regardless of the condition, the produced acids were mainly butyric and acetic acids followed by propionic acid. The OL had a direct impact on the total organic acid concentration with higher concentrations at the highest OL (40 gCOD L\u22121). pH affected the concentration of individual organic acid, with the highest fermentation products (FP) diversity attained at pH 5.0 and OL of 40 gCOD L\u22121. To assess the potential application of organic acids for biopolymers (such as polyhydroxyalkanoates) production, the content in hydroxybutyrate (HB) and hydroxyvalerate (HV) monomers was estimated from the respective precursors produced at each pH and OL. The content in HV precursors increased with pH, with a maximum at pH 6.0 (ca. 16% C-mol basis). The acidogenic fermentation of BSG hydrolysate was also assessed in continuous operation, using an expanded granular sludge bed reactor (EGSB). It was shown that the BSG hydrolysate was successfully converted to VFAs without pH control, achieving higher productivities than in the batch operation mode.<\/jats:p>","DOI":"10.3390\/app11073222","type":"journal-article","created":{"date-parts":[[2021,4,3]],"date-time":"2021-04-03T22:03:36Z","timestamp":1617487416000},"page":"3222","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["A Two-Stage Process for Conversion of Brewer\u2019s Spent Grain into Volatile Fatty Acids through Acidogenic Fermentation"],"prefix":"10.3390","volume":"11","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9338-328X","authenticated-orcid":false,"given":"Eliana C.","family":"Guarda","sequence":"first","affiliation":[{"name":"UCIBIO-REQUIMTE, Departamento de Qu\u00edmica, Faculdade de Ci\u00eancias e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-2364-0284","authenticated-orcid":false,"given":"Ana Catarina","family":"Oliveira","sequence":"additional","affiliation":[{"name":"UCIBIO-REQUIMTE, Departamento de Qu\u00edmica, Faculdade de Ci\u00eancias e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"given":"S\u00edlvia","family":"Antunes","sequence":"additional","affiliation":[{"name":"UCIBIO-REQUIMTE, Departamento de Qu\u00edmica, Faculdade de Ci\u00eancias e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9430-4640","authenticated-orcid":false,"given":"Filomena","family":"Freitas","sequence":"additional","affiliation":[{"name":"UCIBIO-REQUIMTE, Departamento de Qu\u00edmica, Faculdade de Ci\u00eancias e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8841-6606","authenticated-orcid":false,"given":"Paula M. L.","family":"Castro","sequence":"additional","affiliation":[{"name":"CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina\u2014Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Universidade Cat\u00f3lica Portuguesa, Rua Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"given":"Anouk F.","family":"Duque","sequence":"additional","affiliation":[{"name":"UCIBIO-REQUIMTE, Departamento de Qu\u00edmica, Faculdade de Ci\u00eancias e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-4000-1836","authenticated-orcid":false,"given":"Maria A. M.","family":"Reis","sequence":"additional","affiliation":[{"name":"UCIBIO-REQUIMTE, Departamento de Qu\u00edmica, Faculdade de Ci\u00eancias e Tecnologia, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,4,3]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jcs.2005.06.001","article-title":"Brewers\u2019 spent grain: Generation, characteristics and potential applications","volume":"43","author":"Mussatto","year":"2006","journal-title":"J. Cereal Sci."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1264","DOI":"10.1002\/jsfa.6486","article-title":"Brewer\u2019s spent grain: A valuable feedstock for industrial applications","volume":"94","author":"Mussatto","year":"2014","journal-title":"J. Sci. 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