Cited by 42Microbial Metabolic Engineering and BioproductionAlgal biology and biofuel productionPhotosynthetic Processes and Mechanisms

Cycling between growth and production phases increases cyanobacteria bioproduction of lactate

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Shabestary, Kiyan, Hernández, Hugo Pineda, Miao, Rui, Ljungqvist, Emil, Hallman, Olivia, Sporre, Emil, Branco dos Santos, Filipe, Hudson, Elton P.·2021·Metabolic Engineering

Abstract

Decoupling growth from product synthesis is a promising strategy to increase carbon partitioning and maximize productivity in cell factories. However, reduction in both substrate uptake rate and metabolic activity in the production phase are an underlying problem for upscaling. Here, we used CRISPR interference to repress growth in lactate-producing Synechocystis sp. PCC 6803. Carbon partitioning to lactate in the production phase exceeded 90%, but CO2 uptake was severely reduced compared to uptake during the growth phase. We characterized strains during the onset of growth arrest using transcriptomics and proteomics. Multiple genes involved in ATP homeostasis were regulated once growth was inhibited, which suggests an alteration of energy charge that may lead to reduced substrate uptake. In order to overcome the reduced metabolic activity and take advantage of increased carbon partitioning, we tested a novel production strategy that involved alternating growth arrest and recovery by periodic addition of an inducer molecule to activate CRISPRi. Using this strategy, we maintained lactate biosynthesis in Synechocystis for 30 days in a constant light turbidostat cultivation. Cumulative lactate titers were also increased by 100% compared to a constant growth-arrest regime, and reached 1 g/L. Further, the cultivation produced lactate for 30 days, compared to 20 days for the non-growth arrest cultivation. Periodic growth arrest could be applicable for other products, and in cyanobacteria, could be linked to internal circadian rhythms that persist in constant light.

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Crossref · 10.1016/j.ymben.2021.09.010

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  • Efforts in metabolic engineering within cyanobacteria are often limited by constraints in metabolic flux and the availability of precursors.

    “Alongside genetic obstacles, efforts in metabolic engineering within cyanobacteria are often limited by constraints in metabolic flux and the availability of precursors.”

    From Cyanobacteria as a Photosynthetic Chassis for Metabolic Pathway Engineering with Heterologous Gene Expression (2026) · cites this paper as [204]

    The Introduction (page unavailable) describes reduced metabolic activity and CO₂ fixation as limits on cyanobacterial production, and discusses redirecting flux from competing pathways. It does not establish that limited precursor availability is often a separate constraint on cyanobacterial metabolic engineering. (LLM, conf=0.82)

    Experimental — accuracy not yet measured
  • Numerous heterologous pathways compete with native cellular processes for carbon intermediates, ATP, and reducing agents such as NADPH.

    “Numerous heterologous pathways compete with native cellular processes for carbon intermediates, ATP, and reducing agents such as NADPH [204].”
  • Establishing a suitable balance between native metabolic functions and heterologous pathway activity remains a significant challenge in the engineering of cyanobacterial strains.

    “Therefore, establishing a suitable balance between native metabolic functions and heterologous pathway activity remains a significant challenge in the engineering of cyanobacterial strains [204].”

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  1. Fokina, O., Chellamuthu, V.-R., Forchhammer, K., Zeth, K., 2010. Mechanism of 2-oxo- glutarate signaling by the Synechococcus elongatus PII signal transduction protein. Proc. Natl. Acad. Sci. U. S. A. 107, 19760-19765.

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Authors
Shabestary, K., Hernández, H. P., Miao, R., Ljungqvist, E., Hallman, O., Sporre, E., Branco dos Santos, F., & Hudson, E. P.
Affiliations
  • Science for Life Laboratory (SE)
  • University of Amsterdam (NL)
Corresponding author
Hudson, Elton P.
Venue
Metabolic Engineering
Publisher
Elsevier BV
Published
2021-11
Volume
68
Pages
131-141
ISSN
1096-7176 (ISSN-L)
OpenAlex
W3203850845
Cited by
42
References
77
Citations by year
2026: 8 · 2025: 7 · 2024: 10 · 2023: 8 · 2022: 9
FWCI
2.12
Type
journal article
Language
en
Open access
Locations
  • Metabolic Engineering (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • UvA-DARE (University of Amsterdam) (submittedVersion, cc-by)
Funders
  • Horizon 2020 Framework Programme
  • Horizon 2020 (760994)
  • Vetenskapsrådet (2020-04329)
  • Novo Nordisk Fonden (NNF20OC0061469, NNF20OC0064371)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Microbial Metabolic Engineering and Bioproduction
  • Physical Sciences › Energy › Renewable Energy, Sustainability and the Environment › Algal biology and biofuel production
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Photosynthetic Processes and Mechanisms
Keywords
cyanobacteria, lactic acid production, Synechocystis sp. PCC 6803, growth arrest, CRISPR interference, carbon allocation, cell factories, CO2 uptake, ATP homeostasis, energy charge, transcriptomics, proteomics
MeSH terms
Lactic Acid, Synechocystis, Clustered Regularly Interspaced Short Palindromic Repeats

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