Bacterial microcompartment-directed polyphosphate kinase promotes stable polyphosphate accumulation in E. coli

Liang, Mingzhi, Frank, Stefanie, Lünsdorf, Heinrich, Warren, Martin J. ORCID: and Prentice, Michael B. (2017) Bacterial microcompartment-directed polyphosphate kinase promotes stable polyphosphate accumulation in E. coli. Biotechnology Journal, 12 (3). ISSN 1860-6768

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Processes for the biological removal of phosphate from wastewater rely on temporary manipulation of bacterial polyphosphate levels by phased environmental stimuli. In E. coli polyphosphate levels are controlled via the polyphosphate-synthesizing enzyme polyphosphate kinase (PPK1) and exopolyphosphatases (PPX and GPPA), and are temporarily enhanced by PPK1 overexpression and reduced by PPX overexpression. We hypothesised that partitioning PPK1 from cytoplasmic exopolyphosphatases would increase and stabilise E. coli polyphosphate levels. Partitioning was achieved by co-expression of E. coli PPK1 fused with a microcompartment-targeting sequence and an artificial operon of Citrobacter freundii bacterial microcompartment genes. Encapsulation of targeted PPK1 resulted in persistent phosphate uptake and stably increased cellular polyphosphate levels throughout cell growth and into the stationary phase, while PPK1 overexpression alone produced temporary polyphosphate increase and phosphate uptake. Targeted PPK1 increased polyphosphate in microcompartments 8-fold compared with non-targeted PPK1. Co-expression of PPX polyphosphatase with targeted PPK1 had little effect on elevated cellular polyphosphate levels because microcompartments retained polyphosphate. Co-expression of PPX with non-targeted PPK1 reduced cellular polyphosphate levels. Thus, subcellular compartmentalisation of a polymerising enzyme sequesters metabolic products from competing catabolism by preventing catabolic enzyme access. Specific application of this process to polyphosphate is of potential application for biological phosphate removal.

Item Type: Article
Additional Information: Funding Information: This research was supported by Health Research Board award HRA_POR/2011/111 to MBP, and has emanated from research supported in part by Science Foundation Ireland (SFI) Grant Numbers 11/TIDA/B2001 and SFI/12/RC/2273. It was also supported by the British Biotechnology and Biological Sciences Research Council (BBSRC), BB/M002969 and BB/H013180. MBP, MJW, ML are named co-inventors on US Patent US9187766 (B2), also currently WO2013045562 (A1), EP2760883 (A1), ”Accumulation of metabolic products in bacterial microcompartments“. Publisher Copyright: Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Uncontrolled Keywords: bacteria,biopolymers,metabolic engineering,microreactors,synthetic biology,applied microbiology and biotechnology,molecular medicine ,/dk/atira/pure/subjectarea/asjc/2400/2402
Faculty \ School: Faculty of Science
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Depositing User: LivePure Connector
Date Deposited: 20 Sep 2022 14:30
Last Modified: 24 Oct 2022 06:52
DOI: 10.1002/biot.201600415

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