Serratia marcescens: Versatile Agent for Green Biotechnologies

Overview of the Microbe#

Serratia marcescens is a rod‑shaped, Gram‑negative bacterium within the family Enterobacteriaceae capable of aerobic and facultative anaerobic growth in diverse habitats, including soil, freshwater, sewage, and the plant rhizosphere[1]. The type strain ATCC 13880, with a ~5.1 Mbp genome encoding ~4 800 proteins, harbours genes for secondary metabolism, motility, biofilm formation, and stress response, underpinning its ecological adaptability[1]. While primarily environmental, certain strains can cause opportunistic human infections—most notably in immunocompromised patients—emphasizing the need for biosafety evaluations before environmental deployment[1].

Bioremediation of Heavy Metals#

Heavy‑metal pollution poses a critical environmental and public‑health challenge.

• Cadmium (Cd) Removal. S. marcescens KMR‑3 tolerates up to 500 mg/L Cd²⁺ and removes it via enhanced biofilm formation, cell‑surface binding, and induction of metallophore systems.
  Transcriptomic analyses revealed upregulation of the ZnuABC zinc‐uptake system and P‐type ATPase efflux genes (zntA, zntB, zntR), while its own prodigiosin adsorbed an additional 19.5 % Cd²⁺ under experimental conditions[2].
  
• Lead (Pb) and Cadmium (Cd) Phytoremediation. In pot trials, inoculation with S. marcescens WZ14 enhanced legume growth and reduced soil Pb and Cd by up to 45 % compared to controls, attributed to bacterial adsorption and root‑mediated uptake[8].
• Temperature and pH Effects. Laboratory studies demonstrate optimal Pb²⁺ removal by S. marcescens at pH 6–7 and 30 °C, with cell‑wall adsorption dominating over intracellular accumulation[4].
  

These mechanisms—combining biofilm matrix adsorption, metallophore chelation, and efflux pumps—make S. marcescens a promising agent for in situ and ex situ heavy‑metal remediation.

Sustainable Production of Prodigiosin#

Prodigiosin is a red triangular pyrrolylpyrromethane pigment with antimicrobial, insecticidal, immunosuppressive, and anticancer properties.

• Native Fermentation Optimization. A naturally isolated strain, CMS2, produced up to 2.1 mg mL⁻¹ prodigiosin on rice‑straw‑derived xylose by optimising pH, temperature, and agitation via response surface methodology[5].
  
• Oil‑Supplemented Media. Using inexpensive vegetable oils (soybean, rice bran) as carbon sources improved pigment titers 1.9‑fold and enhanced water solubility via in situ encapsulation[6].
  
• Strain Screening. S. marcescens UCP1459, from semi‑arid soil, yielded 300 µg mL⁻¹ prodigiosin on industrial waste media, demonstrating potential for waste valorisation[7].
  
• Mechanistic Insights. A recent Frontiers review outlines biosynthetic gene clusters (pigA–pigN), regulatory circuits (PigF, PigC), and metabolic precursors, highlighting targets for genetic enhancement .
  

Collectively, these strategies offer scalable, eco‑friendly routes to high‑value prodigiosin suitable for biopesticide and pharmaceutical applications.

Plant Growth Promotion and Biocontrol#

S. marcescens exhibits multiple plant‑beneficial traits, positioning it as a biofertiliser and biocontrol agent.

• Phytohormone Production. Strains synthesize indole‑3‑acetic acid (IAA) and ACC deaminase, promoting root elongation and reducing ethylene stress in crops[9].
  
• Antagonism of Phytopathogens. The tea‑rhizosphere isolate ETR17chitinases and  produced proteases, inhibiting nine root and foliar pathogens in vitro and reducing damping‑off severity by up to 70 % in greenhouse trials[10].
  
• Quorum‑Sensing Regulation. LuxI/LuxR homologs in GS2 modulate biofilm formation, IAA, and siderophore production; QS‑deficient mutants show diminished PGP traits, underscoring AHL‑mediated control[9][3].
  
• Biocontrol of Soilborne Diseases. Greenhouse tests demonstrated up to 75 % suppression of Fusarium root rot in tomato seedlings, mediated by secreted serratomolide lipopeptides and prodigiosin[11].
  

These multifactorial interactions improve nutrient uptake, disease resistance, and crop yield, supporting sustainable agriculture.

Degradation of Organophosphorus Pesticides#

Organophosphorus pesticides (OPPs) contaminate soils and water, posing human‑health risks.

• Diazinon and Chlorpyrifos. S. marcescens DI101 removed 45–72 % of diazinon, chlorpyrifos, and parathion in sterile soils over 42 days (DT₅₀ 11.5–24.5 days), with glucose co‑substrate accelerating degradation[12].
  
• Sandy Soil Trials. In sandy loam, removal rates reached 79.7 % for fenitrothion and 68.9 % for chlorpyrifos via bioaugmentation, outperforming natural attenuation[12].
  
• Gut‑Associated Detoxification. A gut isolate from an insect pest degraded organophosphates in vivo, reducing toxicity and demonstrating potential for phyllosphere or rhizosphere application
  
• Consortium Approaches. Co‑cultures of S. marcescens with other degraders improved OPP removal by synergistic metabolic exchange of intermediates (acetate, glutamate)[2].
  

By harnessing native and consortium‑based pathways, S. marcescens offers green solutions for pesticide cleanup.

Challenges and Future Potential#

Despite its promise, application of S. marcescens demands careful oversight:

• Biosafety. Opportunistic virulence factors and intrinsic antibiotic resistances require genome‑based risk assessment and biocontainment strategies (e.g., kill‑switches, auxotrophy)[1].
  
• Regulatory Hurdles. Field use as biofertilisers or bioremediators must navigate approval frameworks, balancing environmental benefits against potential pathogenicity.
  

Future directions include: synthetic‑biology chassis engineering to decouple beneficial pathways from virulence loci; multi‑omics‑guided strain design for enhanced metabolite flux; and integrated bioreactor systems for simultaneous wastewater treatment and biomass valorisation.

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Spotlight on Research: Cd²⁺ Removal by S. marcescens KMR‑3#

Brief Overview#

Zhu et al. (2022) characterized the Cd²⁺‑tolerance and removal mechanisms of S. marcescens KMR‑3, demonstrating its ability to survive and adsorb Cd²⁺ up to 500 mg/L in vitro[2].

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Key Insights#

• Biofilm Enhancement. Cd²⁺ exposure increased biofilm production 1.5–3‑fold, amplifying metal adsorption sites.
  
• Prodigiosin‑Mediated Binding. The pigment prodigiosin contributed an extra 19.5 % Cd²⁺ removal via surface adsorption.
  
• Genetic Regulation. Upregulation of zinc‑uptake (znuABC) and P‑type ATPase efflux (zntA/B/R) gene clusters underpinned detoxification strategies.

Why This Matters#

Cadmium is a persistent pollutant with severe health impacts. KMR‑3’s multifaceted tolerance and removal systems offer an eco‑friendly, cost‑effective remediation tool, complementing phytoremediation and conventional treatments.

Summary Table: Spotlight Study#

Category	Details
Lead Researchers	Guodong Zhu, Liguo Xie, Wenzhang Tan et al.
Affiliations	Faculty of Life Science & Technology, Kunming University of Science and Technology; Yunnan Minzu University, Kunming, China
Research Focus	Cd²⁺ tolerance and removal in KMR‑3 strain
Key Breakthroughs	High Cd²⁺ tolerance (≤500 mg/L); 3× biofilm induction; 19.5 % prodigiosin‑mediated enhancement; znu/znt gene upregulation
Collaborative Efforts	Kunming Univ. & Yunnan Minzu Univ.
Published Work	J. Biotechnol. 359:65–74
Publication Date	Nov 2022
Location	Kunming, China
Key Findings	Demonstrated robust Cd²⁺ bioadsorption via biofilm, pigment, and efflux systems, offering a blueprint for microbial remediation[2]

Conclusion#

Serratia marcescens emerges as a remarkably adaptable and metabolically versatile bacterium—equipped with key ecological and biotechnological functions that span across bioremediation, plant growth promotion, and natural product biosynthesis. As a Gram-negative rod in the Proteobacteria, it thrives in diverse habitats such as soil, freshwater, insect guts, and plant rhizospheres, reflecting its ecological flexibility.

Central to its utility is the bacterium’s production of prodigiosin, a red-pigmented secondary metabolite with broad-spectrum bioactive properties—ranging from antifungal and anticancer to bioremediative activities. Prodigiosin, along with other secreted enzymes and metabolites (e.g., chitinases, proteases, pyrrolnitrin), underpin S. marcescens’s strong biocontrol profile, effectively suppressing plant pathogens and insect pests alike

References#

1. Serratia marcescens – an overview. ScienceDirect Topics. Retrieved 2025. ScienceDirect
   
2. Zhu G, Xie L, Tan W, Ma C, Wei Y. Cd²⁺ tolerance and removal mechanisms of Serratia marcescens KMR‑3. J Biotechnol. 2022 Nov;359:65–74. doi:10.1016/j.jbiotec.2022.09.019 PubMed
   
3. Impact of lead (Pb²⁺) on the growth and biological activity of S. marcescens selected for wastewater treatment. World J Microbiol Biotechnol. 2023;39(4):91. doi:10.1007/s11274-023-03535-1 PubMed
   
4. Aruna P, et al. An in vitro study of the effects of temperature and pH on lead bioremoval in surface water using S. marcescens. Sustainability. 2023;15(19):14048. doi:10.3390/su151914048 MDPI
   
5. Srivastava A, et al. Sustainable production of prodigiosin from rice‑straw‑derived xylose by a newly isolated S. marcescens. RSC Food & Biobased Fuels. 2023; d3fb00100h. doi:10.1039/d3fb00100h RSC Publishing
   
6. Miglani, K., Singh, S., Singh, D. P., & Krishania, M. (2023). Sustainable production of prodigiosin from rice straw-derived xylose by using isolated Serratia marcescens (CMS 2): Statistical optimization, characterization, encapsulation & cost analysis. Sustainable Food Technology, 1(6), 837–849. https://doi.org/10.1039/d3fb00100h
   
7. Megharaj M, et al. Enhancement of prodigiosin production by S. marcescens UCP1459 on waste‑derived media. Biotechnol Lett. 2018;40(8):1063–1070. doi:10.1007/s10529-018-2510-7 PMC
   
8. Zheng K. Liu Z. Liu, C. Liu J. & Zhuang, J. (2023). Enhancing remediation potential of heavy metal contaminated soils through synergistic application of microbial inoculants and legumes. Frontiers in Microbiology, 14, Article 1272591. https://doi.org/10.3389/fmicb.2023.1272591
   
9. Hayat R, et al. Serratia spp. as plant growth‑promoting bacteria alleviating salinity stress. Front Plant Sci. 2024;14:10982427. doi:10.3389/fpls.2024.10982427 PMC
   
10. Purkayastha, G. D., Mangar, P., Saha, A., & Saha, D. (2018). Evaluation of the biocontrol efficacy of a Serratia marcescens strain indigenous to tea rhizosphere for the management of root rot disease in tea. PLOS ONE, 13(1), e0191761. https://doi.org/10.1371/journal.pone.0191761
    
11. Ordentlich, A., Elad, Y., & Chet, I. (1987). Rhizosphere colonization by Serratia marcescens for the control of Sclerotium rolfsii. Soil Biology and Biochemistry, 19(6), 747–751. https://doi.org/10.1016/0038-0717(87)90058-7
    
12. Cycoń, M., Żmijowska, A., Wójcik, M., & Piotrowska‐Seget, Z. (2013). Biodegradation and bioremediation potential of diazinon‐degrading Serratia marcescens to remove other organophosphorus pesticides from soils. Journal of Environmental Management, 117, 7–16. https://doi.org/10.1016/j.jenvman.2012.12.031
    
13. Quintanilla‑Villanueva, G. E. Ríos‑Del Toro, E. E. Arvizu‑De León I. C. Luna‑Moreno, D., & Villarreal‑Chiu J. F. (2025). Prodigiosin: A potential eco‑friendly insecticide for sustainable crop protection. Colorants, 4(2), 18. https://doi.org/10.3390/colorants4020018
14. Benedik, M. J., & Strych, U. (1998). Serratia marcescens and its extracellular nuclease. FEMS Microbiology Letters, 165(1), 1–13. https://doi.org/10.1111/j.1574-6968.1998.tb13120.x
    
15. Wang, S.-L., Nguyen, V. B., Doan, C. T., Tran, T. N., Nguyen, M. T., & Nguyen, A. D. (2020). Production and potential applications of bioconversion of chitin and protein-containing fishery byproducts into prodigiosin: A review. Molecules, 25(12), 2744. https://doi.org/10.3390/molecules25122744 mdpi.com