Growth engineering of <i>Synechococcus elongatus</i> PCC 7942 for mixotrophy under natural light conditions for improved feedstock production

Sarnaik, Aditya; Pandit, Reena; Lali, Arvind

doi:10.1002/btpr.2490

Cited by 13 publications

(5 citation statements)

References 54 publications

(80 reference statements)

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“…To test, we have applied it to Synechococcus elongatus ( S . elongatus ) (Sarnaik et al ., 2017) and successfully observed the pili of S . elongatus PCC 7942 (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…This would be applicable for other bacteria that have similar pili system as P. aeruginosa, or in general, systems that belong to type IV filament superfamilies (Chiang et al, 2005;Gibiansky et al, 2010;Giltner et al, 2010;Jin et al, 2011;Seitz and Blokesch, 2013;Vargas et al, 2013). To test, we have applied it to Synechococcus elongatus (S. elongatus) (Sarnaik et al, 2017) and successfully observed the pili of S. elongatus PCC 7942 (Fig. S7), which illustrates the generality of our method.…”

Section: Characterization Of Pili Morphology and Tfp-driven Twitching Motility By Direct Visualization Of Tfpmentioning

confidence: 88%

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A simple, switchable pili‐labelling method by plasmid‐based replacement of pilin

Zhang

Sun

et al. 2021

Environmental Microbiology

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Summary Labelling of Type IV pili (TFP) can greatly improve our understanding of the pivotal roles of TFP in a variety of bacterial activities including motility, surface sensing and DNA‐uptake etc. Here we show a simple and switchable pili‐labelling method by plasmid‐based inducible replacement of PilA without genetic modification in bacterial genome employed by complicated methods. Using this method, we characterized pili morphology and twitching motility of Pseudomonas aeruginosa in details. More importantly, we demonstrate its application in studying the replenishment dynamics of pilin pool of P. aeruginosa.

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“…To test, we have applied it to Synechococcus elongatus ( S . elongatus ) (Sarnaik et al ., 2017) and successfully observed the pili of S . elongatus PCC 7942 (Fig.…”

Section: Resultsmentioning

confidence: 99%

Section: Characterization Of Pili Morphology and Tfp-driven Twitching Motility By Direct Visualization Of Tfpmentioning

confidence: 88%

A simple, switchable pili‐labelling method by plasmid‐based replacement of pilin

Zhang

Sun

et al. 2021

Environmental Microbiology

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“…Specifically, chlorophyll a serving as major roles in both light harvesting and energy conversion showed decreased yield in YQ3-xyl compared with WT (Additional file 1 : Fig. S4A) [ 31 ], indicating the reduced dependency on light for energy metabolism while extra energy source, such as pentose phosphate pathway, was provided due to xylose utilization in YQ3-xyl [ 32 ]. The yield of carotenoid had no significant change, however, carotenoid/chlorophyll a , which relates to the deployment of photoprotective mechanism [ 30 , 33 ], were increased in YQ3-xyl (Additional file 1 : Fig.…”

Section: Resultsmentioning

confidence: 99%

Transcriptomics and metabolomics of engineered Synechococcus elongatus during photomixotrophic growth

Tan

Cao

et al. 2022

Microb Cell Fact

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Background Converting carbon dioxide (CO2) into value-added chemicals using engineered cyanobacteria is a promising strategy to tackle the global warming and energy shortage issues. However, most cyanobacteria are autotrophic and use CO2 as a sole carbon source, which makes it hard to compete with heterotrophic hosts in either growth or productivity. One strategy to overcome this bottleneck is to introduce sugar utilization pathways to enable photomixotrophic growth with CO2 and sugar (e.g., glucose and xylose). Advances in engineering mixotrophic cyanobacteria have been obtained, while a systematic interrogation of these engineered strains is missing. This work aimed to fill the gap at omics level. Results We first constructed two engineered Synechococcus elongatus YQ2-gal and YQ3-xyl capable of utilizing glucose and xylose, respectively. To investigate the metabolic mechanism, transcriptomic and metabolomic analysis were then performed in the engineered photomixotrophic strains YQ2-gal and YQ3-xyl. Transcriptome and metabolome of wild-type S. elongatus were set as baselines. Increased abundance of metabolites in glycolysis or pentose phosphate pathway indicated that efficient sugar utilization significantly enhanced carbon flux in S. elongatus as expected. However, carbon flux was redirected in strain YQ2-gal as more flowed into fatty acids biosynthesis but less into amino acids. In strain YQ3-xyl, more carbon flux was directed into synthesis of sucrose, glucosamine and acetaldehyde, while less into fatty acids and amino acids. Moreover, photosynthesis and bicarbonate transport could be affected by upregulated genes, while nitrogen transport and assimilation were regulated by less transcript abundance of related genes in strain YQ3-xyl with utilization of xylose. Conclusions Our work identified metabolic mechanism in engineered S. elongatus during photomixotrophic growth, where regulations of fatty acids metabolism, photosynthesis, bicarbonate transport, nitrogen assimilation and transport are dependent on different sugar utilization. Since photomixotrophic cyanobacteria is regarded as a promising cell factory for bioproduction, this comprehensive understanding of metabolic mechanism of engineered S. elongatus during photomixotrophic growth would shed light on the engineering of more efficient and controllable bioproduction systems based on this potential chassis.

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“…S. elongatus is an obligate photoautotroph, and the uptake of organic carbon has been obtained solely by genetic engineering (McEwen et al, 2013;Sarnaik et al, 2017;Sarnaik et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Coupling dairy wastewaters for nutritional balancing and water recycling: sustainable heterologous 2-phenylethanol production by engineered cyanobacteria

Usai,

Cordara,

Mazzocchi

et al. 2024

Front. Bioeng. Biotechnol.

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Microalgae biotechnology is hampered by the high production costs and the massive usage of water during large-volume cultivations. These drawbacks can be softened by the production of high-value compounds and by adopting metabolic engineering strategies to improve their performances and productivity. Today, the most sustainable approach is the exploitation of industrial wastewaters for microalgae cultivation, which couples valuable biomass production with water resource recovery. Among the food processing sectors, the dairy industry generates the largest volume of wastewaters through the manufacturing process. These effluents are typically rich in dissolved organic matter and nutrients, which make it a challenging and expensive waste stream for companies to manage. Nevertheless, these rich wastewaters represent an appealing resource for microalgal biotechnology. In this study, we propose a sustainable approach for high-value compound production from dairy wastewaters through cyanobacteria. This strategy is based on a metabolically engineered strain of the model cyanobacterium Synechococcus elongatus PCC 7942 (already published elsewhere) for 2-phenylethanol (2-PE). 2-PE is a high-value aromatic compound that is widely employed as a fragrance in the food and cosmetics industry thanks to its pleasant floral scent. First, we qualitatively assessed the impact of four dairy effluents on cyanobacterial growth to identify the most promising substrates. Both tank-washing water and the liquid effluent of exhausted sludge resulted as suitable nutrient sources. Thus, we created an ideal buffer system by combining the two wastewaters while simultaneously providing balanced nutrition and completely avoiding the need for fresh water. The combination of 75% liquid effluent of exhausted sludge and 25% tank-washing water with a fine-tuning ammonium supplementation yielded 180 mg L−1 of 2-PE and a biomass concentration of 0.6 gDW L-1 within 10 days. The mixture of 90% exhausted sludge and 10% washing water produced the highest yield of 2-PE (205 mg L−1) and biomass accumulation (0.7 gDW L−1), although in 16 days. Through these treatments, the phosphates were completely consumed, and nitrogen was removed in a range of 74%–77%. Overall, our approach significantly valorized water recycling and the exploitation of valuable wastewaters to circularly produce marketable compounds via microalgae biotechnology, laying a promising groundwork for subsequent implementation and scale-up.

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Growth engineering of Synechococcus elongatus PCC 7942 for mixotrophy under natural light conditions for improved feedstock production

Cited by 13 publications

References 54 publications

A simple, switchable pili‐labelling method by plasmid‐based replacement of pilin

A simple, switchable pili‐labelling method by plasmid‐based replacement of pilin

Transcriptomics and metabolomics of engineered Synechococcus elongatus during photomixotrophic growth

Coupling dairy wastewaters for nutritional balancing and water recycling: sustainable heterologous 2-phenylethanol production by engineered cyanobacteria

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