Corynebacterium glutamicum single-cell protein produced with fermented spent coffee grounds extract supports L-lactate and acetate production by lactic acid bacteria and bifidobacteria
Year: 2026
Type: article
Abstract: Spent coffee grounds (SCG) contain substantial organic matter, but much of it is not readily accessible for microbial cultivation. This study evaluated fermented spent coffee grounds (FSCG) extract as a nutrient source for Corynebacterium glutamicum single-cell protein (SCP) production and assessed the resulting biomass as a substrate for L-lactate and acetate production by lactic acid bacteria and bifidobacteria. SCG were subjected to solid-state fermentation, and the FSCG extract produced by 15 days of once-daily stirring followed by 30 days of static incubation was selected for C. glutamicum -SCP production. At 5% (w/v), the selected extract yielded 4.91 g/L of recovered SCP; the corresponding values were 4.76 g/L in minimal medium and 4.85 g/L in complex medium. FSCG extract-derived and complex medium-derived C. glutamicum -SCP contained acid-hydrolyzable rhamnose, arabinose/galactose, mannose, and glucose, together with alkali-extractable glycogen. Both SCP preparations supported strain-dependent L-lactate and acetate production by lactic acid bacteria and bifidobacteria. In a 22-strain mixed culture, acetate production reached 1.83 mg/mL with complex medium-derived C. glutamicum -SCP and 2.28 mg/mL with FSCG extract-derived C. glutamicum -SCP. Both values were significantly higher than that obtained under the glucose-containing condition, and acetate production was significantly higher with FSCG extract-derived C. glutamicum -SCP than with complex medium-derived C. glutamicum -SCP. These findings provide proof of concept for integrating SCG valorization with C. glutamicum -SCP production and demonstrate that the resulting SCP supports subsequent organic acid formation by lactic acid bacteria and bifidobacteria.
Authors: Sehyeon Park, Taeyeon Kim, Soyeon Lee, Pil Kim
Institution: Catholic University of Korea
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,353
OpenAlex ID: W7223648630