[P003] Poster

12:10 PM - 1:00 PM JST(3:10 AM - 4:00 AM UTC)

[P02-269] Valorization of brewer’s spent yeast extracts as nitrogen sources for bacterial cellulose production

○José Manuel Domínguez¹, Mónica Salvador-Cardona¹, Martín Cid-Fernández¹, Aida Ochogavias¹, Ricardo Pinheiro de Souza Oliveira², Alicia Paz¹ (1. Universidade de Vigo (Spain), 2. USP (Brazil))

Keywords:

bacterial cellulose,brewer’s spent yeast,circular bioeconomy,industrial by-products,nitrogen source,bioprocess sustainability

The high cost of nitrogen sources used in conventional culture media limits the industrial production of bacterial cellulose (BC). Brewer’s spent yeast (BSY), a major by-product of the brewing industry, represents a potential alternative nitrogen source. This study aimed to evaluate the use of BSY-derived extracts as substitutes for commercial yeast extract in BC production by Komagataeibacter xylinus. xylinusCECT 473 was cultivated in GY medium supplemented with different yeast extracts derived from brewer’s spent yeast (E, S and AU), which were compared with a commercial yeast extract. Glucose consumption, pH evolution and BC production were monitored. Fermentation time (5, 10 and 15 days) was also evaluated to determine the optimal cultivation period.Extracts E and S showed significantly higher BC production compared with the commercial yeast extract during the initial stages of fermentation. The maximum BC production (2.26 g/L) was obtained using extract E after 10 days of cultivation. In contrast, extract AU resulted in lower BC production, possibly due to the presence of inhibitory phenolic compounds derived from hops.These results indicate that brewer’s spent yeast extracts can provide suitable nutrients and metabolic cofactors for BC biosynthesis. However, the composition of the extracts plays an important role in microbial performance and cellulose production.Brewer’s spent yeast extracts represent a promising and sustainable alternative nitrogen source for BC production. Their use could reduce medium costs while promoting the valorization of brewing industry by-products within circular bioeconomy strategies.