Thauera aminoaromatica MZ1T Identified as a Polyhydroxyalkanoate-Producing Bacterium within a Mixed Microbial Consortium

Abstract

Polyhydroxyalkanoates (PHAs) form a highly promising class of bioplastics for the transition from fossil fuel-based plastics to bio-renewable and biodegradable plastics. Mixed microbial consortia (MMC) are known to be able to produce PHAs from organic waste streams. Knowledge of key-microbes and their characteristics in PHA-producing consortia is necessary for further process optimization and direction towards synthesis of specific types of PHAs. In this study, a PHA-producing mixed microbial consortium (MMC) from an industrial pilot plant was characterized and further enriched on acetate in a laboratory-scale selector with a working volume of 5 L. 16S-rDNA microbiological population analysis of both the industrial pilot plant and the 5 L selector revealed that the most dominant species within the population is Thauera aminoaromatica MZ1T, a Gram-negative beta-proteobacterium belonging to the order of the Rhodocyclales. The relative abundance of this Thauera species increased from 24 to 40% after two months of enrichment in the selector-system, indicating a competitive advantage, possibly due to the storage of a reserve material such as PHA. First experiments with T. aminoaromatica MZ1T showed multiple intracellular granules when grown in pure culture on a growth medium with a C:N ratio of 10:1 and acetate as a carbon source. Nuclear magnetic resonance (NMR) analyses upon extraction of PHA from the pure culture confirmed polyhydroxybutyrate production by T. aminoaromatica MZ1T.

Microbial Blends: Terminology Overview and Introduction of the Neologism “Skopobiota”

“…According to this analysis and in light of the fact that they are often used interchangeably, we conclude that the terms microbial consortium, synthetic microbial community, microbial cocktail, and synthetic microbiome Del Frari et al, 2019;El Hage et al, 2019;Colpa et al, 2020;Pereira et al, 2020;Dai et al, 2021 Chen et al, 2018;Wang et al, 2018;Rafique et al, 2019;Rékási et al, 2019;Dong et al, 2020;Singh et al, 2020 Synthetic microbial community Shahab et al, 2018;Carrión et al, 2019;Christiaens et al, 2019;Honjo et al, 2019;Wang et al, 2020;Krieger et al, 2021 Microbial cocktail Moreira et al, 2017;Qu et al, 2018;Pasaribu et al, 2019;Pires et al, 2019;Tobin et al, 2020;Zheng et al, 2020 Synthetic microbiome Venturelli et al, 2018;Timmis et al, 2019;Vandeplassche et al, 2019;Voges et al, 2019;Koskella, 2020;Mabwi et al, 2021 The symbol "+" indicates the presence of the specific key characteristic, while the symbol "-" indicates its absence, in association with each term (refer to the text for the definition of the concepts of each key characteristic).…”

Effects of the Sludge Retention Time and Carbon Source on Polyhydroxyalkanoate-Storing Biomass Selection under Aerobic-Feast and Anoxic-Famine Conditions

“…The excised bands in period 2 represented an unknown strain of α-Proteobacteria (S9) and the genera Paracoccus (S13) and Thauera (S16). Strains belonging to both of these genera are well-known PHA producers and are often detected among the most abundant PHA-storing bacteria in S-SBRs fed with VFAs under F/F conditions. ,− In period 3, both the liquid fraction of the fermenter (F) and the anaerobic supernatant (S) were supplied as carbon sources to the S-SBR, and many bands were observed in both cases. The main supernatant bands were sequenced and were found to represent the classes Firmicutes (N5) and α-Proteobacteria (N6).…”

Polyhydroxyalkanoate Production from Food Waste Coupled with Aerobic Nitrate Reduction

“…Additionally, 24–40% of the T. aminoaromatica strain MZ1T was enriched in a PHA production reactor . However, there is no research focusing on the coupled relationship between PHA synthesis and nitrogen utilization for T.…”

“…Additionally, 24−40% of the T. aminoaromatica strain MZ1T was enriched in a PHA production reactor. 46 However, there is no research focusing on the coupled relationship between PHA synthesis and nitrogen utilization for T. aminoaromatica. This study clarified the coupled mechanism at the gene level and applied it in real scenarios.…”