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Extraction of Structural Extracellular Polymeric Substances from Aerobic Granular Sludge
Published on: September 26, 2016
Effective methods for extracting extracellular polymeric substances from Shewanella oneidensis MR-1
You-Fen Dai1, Yong Xiao2, En-Hua Zhang2
1CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen, Fujian Province 361021, China E-mail: yxiao@iue.ac.cn; College of Life Sciences, Fujian Normal University, Fuzhou 350108, China.
Gentle heating (40°C) and EDTA treatments are effective for extracting extracellular polymeric substances (EPS) from Shewanella oneidensis MR-1. These methods minimize bacterial cell damage while yielding significant amounts of proteins and polysaccharides.
Area of Science:
- Microbiology
- Biochemistry
- Analytical Chemistry
Background:
- Extracellular polymeric substances (EPS) are vital for bacterial aggregation and survival.
- Understanding EPS composition and extraction is crucial for microbial studies.
- Shewanella oneidensis MR-1 is a model organism for studying microbial processes.
Purpose of the Study:
- To evaluate and compare different methods for extracting EPS from Shewanella oneidensis MR-1.
- To identify extraction techniques that are both effective and minimize bacterial cell lysis.
- To characterize the yield and composition of EPS obtained from various methods.
Main Methods:
- Extraction of EPS using centrifugation, heating (40-60°C), H2SO4, EDTA, and NaOH.
- Analysis of bacterial cell integrity using scanning electron microscopy and flow cytometry.
- Quantification of proteins and polysaccharides in EPS using chemical analysis and 3D excitation-emission matrix (EEM) spectroscopy.
Main Results:
- H2SO4, NaOH, and heating ≥45°C caused significant bacterial cell lysis.
- Heating at 40°C yielded high amounts of EPS (7.12 mg/g protein, 1.60 mg/g polysaccharide).
- EDTA treatment resulted in lower EPS yield (5.15 mg/g protein, 1.30 mg/g polysaccharide) but minimal cell lysis.
- 3D EEM spectra indicated protein-like substances in EPS, correlating with protein concentration.
Conclusions:
- Heating at 40°C and EDTA treatment are optimal for EPS extraction from Shewanella oneidensis MR-1.
- These methods balance EPS yield and purity with minimal disruption to bacterial cells.
- The study provides valuable insights for selecting appropriate EPS extraction techniques in microbial research.
