Enhanced biodegradation of atrazine by bacteria encapsulated in organically modified silica gels

Joey J. Benson, Jonathan K. Sakkos, Adi Radian, Lawrence P Wackett, Alptekin Aksan

Research output: Contribution to journalArticle

Abstract

Biodegradation by cells encapsulated in silica gel is an economical and environmentally friendly method for the removal of toxic chemicals from the environment. In this work, recombinant E. coli expressing atrazine chlorohydrolase (AtzA) were encapsulated in organically modified silica (ORMOSIL) gels composed of TEOS, silica nanoparticles (SNPs), and either phenyltriethoxysilane (PTES) or methyltriethoxysilane (MTES). ORMOSIL gels adsorbed much higher amounts of atrazine than the hydrophilic TEOS gels. The highest amount of atrazine adsorbed by ORMOSIL gels was 48.91 × 10−3 μmol/ml gel, compared to 8.71 × 10−3 μmol/ml gel by the hydrophilic TEOS gels. Atrazine biodegradation rates were also higher in ORMOSIL gels than the TEOS gels, mainly due to co-localization of the hydrophobic substrate at high concentrations in close proximity of the encapsulated bacteria. A direct correlation between atrazine adsorption and biodegradation was observed unless biodegradation decreased due to severe phase separation. The optimized PTES and MTES gels had atrazine biodegradation rates of 0.041±0.003 and 0.047±0.004 μmol/ml gel, respectively. These rates were approximately 80% higher than that measured in the TEOS gel. This study showed for the first time that optimized hydrophobic gel material design can be used to enhance both removal and biodegradation of hydrophobic chemicals.

LanguageEnglish (US)
Pages57-68
Number of pages12
JournalJournal of Colloid And Interface Science
Volume510
DOIs
StatePublished - Jan 15 2018

Fingerprint

Atrazine
Herbicides
Silica Gel
Silica gel
Biodegradation
Bacteria
Gels
Poisons
Silicon Dioxide
Phase separation
Escherichia coli
Silica
Nanoparticles
Adsorption

Keywords

  • Atrazine
  • Encapsulated bacteria
  • Hydrophobic silica gel
  • MTES
  • ORMOSIL
  • PTES
  • TEOS

Cite this

Enhanced biodegradation of atrazine by bacteria encapsulated in organically modified silica gels. / Benson, Joey J.; Sakkos, Jonathan K.; Radian, Adi; Wackett, Lawrence P; Aksan, Alptekin.

In: Journal of Colloid And Interface Science, Vol. 510, 15.01.2018, p. 57-68.

Research output: Contribution to journalArticle

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