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From fruit juice wastewater to biopolymer – How the mixed microbial culture and PHA content develop over time

Year: 2024
Type: article
Abstract: Biodegradable polymers in the form of polyhydroxyalkanoates (PHA) were produced using residual streams from the fruit juice industry and excess sludge from a municipal sewage treatment plant. Initially, PHA-synthesising bacteria were enriched through a feast-famine regime, supplying the feedstock in a 12 h cycle. The development of the PHA accumulation potential was investigated closely during a 14-day-long experiment, taking hourly samples during several eight-hour-long batch accumulations. Thus, the substrate was provided to the enriched biomass using a feed-on-demand strategy based on the increase of the dissolved oxygen concentration. Hereby, the PHA content of the mixed microbial culture (MMC) increased from 8 % up to 65 % of the dry matter after 6 days. At the same time a stable metabolism of the MMC could be observed, showing a regular feeding pattern. Gas chromatography was used to analyse the monomeric composition of the produced PHA, revealing changes in the composition of hydroxybutyrate (HB), hydroxyvalerate (HV), and hydroxy hexanoate (HH). Additionally, molecular analysis of the microbial community composition showed a shift in the relative abundance of potential PHA-producing bacteria. Despite this shift, the PHA productivity of the biocenosis remained nearly stable and followed the same pattern of the relative abundance of potential PHA producers, demonstrating the system’s resilience and functional redundancy.
DOI: 10.1016/j.cej.2024.158314
Language: English
Subfield: Biomaterials
Open Access status: hybrid
Estimated APC paid: $4,490
OpenAlex ID: W4405143121
FWCI: 1.002
Cites: 52
Cited by: 12
Related to: 10