Characterization of Exopolysaccharide Produced by Pseudomonas sp. PFAB4 for Synthesis of EPS-Coated AgNPs with Antimicrobial Properties
Thermal ecosystems like hot springs are exclusive habitat of thermotolerant microorganisms that produce exopolysaccharides (EPS). In this study, EPS produced by a hot spring origin Pseudomonas species is structurally elucidated.The EPS is highly thermostable (Td 289.98 °C), has low molecular weight (1510 Da) and is rhamnoglucose type consisting α-(1 → 3) linked to L-Rhap and α-(1 → 6) linked to d-Glc substituted with O-acetyl groups. Irregular EPS sheets with smooth surface were observed that signify the compact structure of the biopolymer; a characteristic plasticized film-like feature. Intra- and inter-molecular aggregation of EPS units are observed in atomic force microscopy. The EPS showed good rheological property at neutral pH. EPS-mediated green synthesis of silver nanoparticles (AgNP) was performed using co-precipitation method. Size of individual AgNPs had a Z-average of 93.6 nm and 0.437 polydispersity index. The EPS-coated AgNPs were moderately monodisperse. These AgNPs also exhibited biocidal property preferentially against gram negative bacteria and some fungi. Incorporating EPS to the metal nanoparticles confers them biocompatibility. Green synthesis of silver nanoparticles has gained considerable attention for its eco-friendliness in nano-medicine and nano-biotechnology. Keeping in context, the results of our study will support a new polysaccharide-mediated green synthesis approach of metal nanoparticles that shows profound antimicrobial property.
KeywordsPseudomonas Exopolysaccharide Silver nanoparticle Green synthesis Biocidal property
The authors would like to thank the UGC-Center of Advanced Study, Department of Botany, The University of Burdwan for pursuing the research activities. AB is thankful for the financial assistance from the SRF (State Funded) [Fc (Sc.) /RS/SF/BOT./2014–15/ 103 (3)]. All the authors would also like to thank Dr. Raja Shunmugam, IISER Kolkata for helping in the advanced polymer chromatographic facility.
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Conflict of interest
The authors declare that they have no conflict of interest.
- 6.Escárcega-González CE, Garza-Cervantes JA, Vázquez-Rodríguez A, Morones-Ramírez JR (2018) Bacterial exopolysaccharides as reducing and/or stabilizing agents during synthesis of metal nanoparticles with biomedical applications. Int J Polym Sci. https://doi.org/10.1155/2018/7045852 CrossRefGoogle Scholar
- 15.Abinaya M, Vaseeharan B, Divya M, Sharmili A, Govindarajan M, Alharbi NS, Kadaikunnan S, Khaled JM, Benelli G (2018) Bacterial exopolysaccharide (EPS)-coated ZnO nanoparticles showed high antibiofilm activity and larvicidal toxicity against malaria and Zika virus vectors. J Trace Elem Med Biol 45:93–103PubMedCrossRefPubMedCentralGoogle Scholar
- 16.Kumari B, Lohar S, Ghosh M, Ta S, Sengupta A, Banerjee PP, Chattopadhyay A, Das D (2016) Structurally characterized Zn2+ selective Ratiometric fluorescence probe in 100% water for HeLa cell imaging: experimental and computational studies. J Fluoresc 26(1):87–103PubMedCrossRefPubMedCentralGoogle Scholar
- 17.Pelczar MJ, Bard RC, Burnett GW (1957) Manual of microbiological methods. McGraw-Hill Book Company, New YorkGoogle Scholar
- 21.Fox A, Morgan SL, Gilbart J (1989) Preparation of alditol acetates and their analysis by gas chromatography (GC) and mass spectrometry (MS). In: Biermann CJ, McGinnis GD (eds) Analysis of carbohydrates by GLC and MS. CRC Press, Boca Raton, pp 87–117Google Scholar