Iglesias-Iglesias R, Portela-Grandío A, Treu L, Campanaro S, Kennes C, Veiga MC. Co-digestion of cheese whey with sewage sludge for caproic acid production: Role of microbiome and polyhydroxyalkanoates potential production.
BIORESOURCE TECHNOLOGY 2021;
337:125388. [PMID:
34166928 DOI:
10.1016/j.biortech.2021.125388]
[Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 06/13/2023]
Abstract
The main aim of this work was to evaluate the efficiency of producing caproic acid and other volatile fatty acids using a co-digestion between cheese whey and sewage sludge in a continuous reactor. The effect of two different feeding regimes (one and two per day) and three hydraulic retention times (HRT) (15, 10 and 6 days) on the organic acids production were studied. The optimal conditions for the process were 10 days HRT, 2 feeding cycles per day, reaching a maximum degree of acidification of 44%. Under these conditions, the most abundant organic acid was caproic acid. The analysis of the microbial community dynamics in the reactor during the HRT changes revealed a microbiome enriched in organisms involved in caproic acid production. Additionally, the production of polyhydroxyalkanoates using the organic acids stream as feeding was verified in a fed-batch experiment obtaining a copolymer formed by hydroxybutyrate, hydroxyvalerate and hydroxyhexanoate.
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