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The brewery industry is under economic and environmental pressure to minimize residual management costs, particularly brewery spent grain (BSG), which accounts for 80-85% (w/w) of the total by-products generated. BSG is a lignocellulosic material primarily composed of carbohydrates, proteins and lipids. Developing a biorefinery model for conversion of BSG into value-added products is a plausible idea. Previous work optimized the pretreatment of BSG with the ionic liquid [N 1112OH ][Gly] and further release of fermentable sugar-containing solutions by enzymatic hydrolysis, using an enzymatic cocktail obtained by solid-state fermentation of BSG with Aspergillus brasiliensis CECT 2700 and Trichoderma reesei CECT 2414. The current work ends the biorefinery process, studying the fermentation of these culture media with two LAB strains, Lactobacillus pentosus CECT 4023 and Lactobacillus plantarum CECT 221, from which the production of organic acids, bacteriocins, and microbial biosurfactants (mBS) was obtained. In addition to the bacteriocin activity observed, a mass balance of the whole biorefinery process quantified the production of 106.4 g lactic acid and 6.76 g mBS with L. plantarum and 116.1 g lactic acid and 4.65 g mBS with L. pentosus from 1 kg of dry BSG. Thus, BSG shows a great potential for waste valorization, playing a major role in the implementation of biomass biorefineries in circular bioeconomy., Competing Interests: Declaration of Competing Interest Authors declare that they have no conflict of interest., (Copyright © 2024. Published by Elsevier B.V.)

Bacillus aryabhattai BA03, a strain isolated in our laboratory, has interesting properties related to the production of natural aromas and flavors. Specifically, we have found that it was able to produce vanillin from ferulic acid (FA). Furthermore, this strain produces high amounts of 4-vinylguaiacol in only 14h, this being the only intermediate metabolite observed in the process. FA is an inexpensive feedstock for the production of natural value-added compounds when extracted from lignocellulosic wastes. In this study, we optimized the operational conditions (temperature, pH and agitation), medium composition and bioconversion technology (batch or fed-batch) to produce vanillin. In a fed-batch process conducted with just one additional supplementation after 24h, the maximal concentration of vanillin (147.1±0.9mg/L) was observed after 216h (Q V =0.681mg/Lh; Y V/fFA =0.082mg/mg) after degrading 90.3% FA. In view of our data, we postulate that Bacillus aryabhattai BA03 carries out a decarboxylation of ferulic acid as a metabolic pathway., (Copyright © 2017 Elsevier B.V. All rights reserved.)