Control of fermentation duration and pH to orient biochemicals and biofuels production from cheese whey

• Published in: Bioresource technology 2019-10, Vol.289, p.121722-121722, Article 121722
• Main Authors: Asunis, F., De Gioannis, G., Isipato, M., Muntoni, A., Polettini, A., Pomi, R., Rossi, A., Spiga, D.
• Format: Article
• Language: English
• Subjects: Biohydrogen; Cheese whey; Dark fermentation; Metabolic pathways modelling; Organic acids
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2019.121722

[Display omitted] •Fermentation of sheep cheese whey performed using exclusively indigenous biomass.•Carbohydrates were converted to lactate that was then degraded to VFAs and H2.•Different metabolites were produced depending on pH and fermentation time.•Maximum lactate yield (23 mmol/g TOCi) was attained at pH 6.0 after 45 h.•Maximum H2 yield (162 L/kg TOCi) was attained at pH 6.0 after 168 h. Batch dark fermentation tests were performed on sheep cheese whey without inoculum addition at different operating pHs, relating the type and production yields of the observed gaseous and liquid by-products to the evolution of fermentation. Cheese whey fermentation evolved over time in two steps, involving an initial conversion of carbohydrates to lactic acid, followed by the degradation of this to soluble and gaseous products including short-chain fatty acids (mainly acetic, butyric and propionic acids) and hydrogen. The operating pH affected the production kinetics and yields, as well as the fermentation pathways. By varying the duration of the fermentation process, different cheese whey exploitation strategies may be applied and oriented to the main production of lactic acid, hydrogen or other organic acids.