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

doi:10.1016/j.jcis.2017.09.044

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 journal › Article › peer-review

18 Scopus citations

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.

Original language	English (US)
Pages (from-to)	57-68
Number of pages	12
Journal	Journal of Colloid And Interface Science
Volume	510
DOIs	https://doi.org/10.1016/j.jcis.2017.09.044
State	Published - Jan 15 2018

Bibliographical note

Funding Information:
This research was supported by a grant from Syngenta Crop Protection , a seed grant from the University of Minnesota BioTechnology Institute , and Vaadia-BARD Postdoctoral Fellowship award no. FI-516-2014 from BARD, the United States-Israel Binational Agricultural Research and Development Fund. Parts of this work were carried out in the Characterization Facility at the University of Minnesota, which receives partial support from NSF though the MRSEC program. Confocal microscopy was done with the help of the University Imaging Centers at the University of Minnesota. NMR work was carried out in the MNMR center at the University of Minnesota, which receives funding from Office of the Vice President for Research, the Medical School, the College of Biological Science, NIH, NSF, and the Minnesota Medical Foundation.

Publisher Copyright:
© 2017 Elsevier Inc.

Keywords

Atrazine
Encapsulated bacteria
Hydrophobic silica gel
MTES
ORMOSIL
PTES
TEOS

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@article{8952434830fb4bb3a5f585872cc682d1,

title = "Enhanced biodegradation of atrazine by bacteria encapsulated in organically modified silica gels",

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. ",

keywords = "Atrazine, Encapsulated bacteria, Hydrophobic silica gel, MTES, ORMOSIL, PTES, TEOS",

author = "Benson, {Joey J.} and Sakkos, {Jonathan K.} and Adi Radian and Wackett, {Lawrence P} and Alptekin Aksan",

note = "Funding Information: This research was supported by a grant from Syngenta Crop Protection , a seed grant from the University of Minnesota BioTechnology Institute , and Vaadia-BARD Postdoctoral Fellowship award no. FI-516-2014 from BARD, the United States-Israel Binational Agricultural Research and Development Fund. Parts of this work were carried out in the Characterization Facility at the University of Minnesota, which receives partial support from NSF though the MRSEC program. Confocal microscopy was done with the help of the University Imaging Centers at the University of Minnesota. NMR work was carried out in the MNMR center at the University of Minnesota, which receives funding from Office of the Vice President for Research, the Medical School, the College of Biological Science, NIH, NSF, and the Minnesota Medical Foundation. Publisher Copyright: {\textcopyright} 2017 Elsevier Inc.",

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doi = "10.1016/j.jcis.2017.09.044",

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AU - Benson, Joey J.

AU - Sakkos, Jonathan K.

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AU - Wackett, Lawrence P

AU - Aksan, Alptekin

N1 - Funding Information: This research was supported by a grant from Syngenta Crop Protection , a seed grant from the University of Minnesota BioTechnology Institute , and Vaadia-BARD Postdoctoral Fellowship award no. FI-516-2014 from BARD, the United States-Israel Binational Agricultural Research and Development Fund. Parts of this work were carried out in the Characterization Facility at the University of Minnesota, which receives partial support from NSF though the MRSEC program. Confocal microscopy was done with the help of the University Imaging Centers at the University of Minnesota. NMR work was carried out in the MNMR center at the University of Minnesota, which receives funding from Office of the Vice President for Research, the Medical School, the College of Biological Science, NIH, NSF, and the Minnesota Medical Foundation. Publisher Copyright: © 2017 Elsevier Inc.

PY - 2018/1/15

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N2 - 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.

AB - 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.

KW - Atrazine

KW - Encapsulated bacteria

KW - Hydrophobic silica gel

KW - MTES

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KW - TEOS

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JO - Journal of Colloid And Interface Science

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ER -

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

Abstract

Bibliographical note

Keywords

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Nikon A1si Spectral Confocal

University Imaging Centers

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

Abstract

Bibliographical note

Keywords

Access

OpenUrl availability

Other files and links

Fingerprint

Equipment

Nikon A1si Spectral Confocal

University Imaging Centers

Cite this