Re-inoculation of autoclaved soil as a non-sterile treatment for xenobiotic sorption and biodegradation studies

L J Shaw, Y Beaton, L A Glover, K Killham, A A Meharg

Research output: Contribution to journalArticle

47 Citations (Scopus)

Abstract

Autoclaved soil is commonly used for the study of xenobiotic sorption and as an abiotic control in biodegradation experiments. Autoclaving has been reported to alter soil physico-chemical and xenobiotic sorption characteristics such that comparison of autoclaved with non-autoclaved treatments in soil aging and bioavailability studies may yield misleading results. Experiments could be improved by using autoclaved soil re-inoculated with indigenous microorganisms as an additional or alternative non-sterile treatment for comparison with the sterile, autoclaved control. We examined the effect of autoclaving (3 x 1 h, 121 degrees C, 103.5 KPa) on the physico-chemical properties of a silt loam soil (pH 7.2, 2.3% organic carbon) and the establishment of indigenous microorganisms reintroduced after autoclaving. Sterilisation by autoclaving significantly (p less than or equal to 0.05) decreased pH (0.6 of a unit) and increased concentrations of water-soluble organic carbon (WSOC; nontreated = 75 mg kg(-1); autoclaved = 1526 mg kg(-1)). The initial first-order rate of C-14-2,4-dichloro-UL-phenol (2,4-DCP) adsorption to non-treated, autoclaved and re-inoculated soil was rapid (K-1 = 16.8-24.4 h(-1)) followed by a slower linear phase (K-2) In comparison with autoclaved soil (0.038% day(-1)), K-2 values were higher for re-inoculated (0.095% day(-1)) and nontreated (0.181% day(-1)) soil. This was attributed to a biological process. The Freundlich adsorption coefficient (K-t) for autoclaved soil was significantly (p less than or equal to 0.05) higher than for re-inoculated or non-treated soil, increased adsorption was attributed to autoclaving-induced changes to soil pH and solution composition. Glucose-induced respiration of autoclaved soil after re-inoculation was initially twice that in the non-treated control, but it decreased to control levels by day 4. This reduction corresponded to a depletion of WSOC. 2, I-DCP mineralisation experiments revealed that the inoculum of nonsterile soil (0.5 g) contained 2,4-DCP-degrading microorganisms capable of survival in autoclaved soil. The lag phase before detection of significant 2,4-DCP mineralisation was reduced (from 7 days to less than or equal to 3 days) by pre-incubation of re-inoculated soils for 7 and 14 days before 2,4-DCP addition. This was attributed to the preferential utilisation of WSOC prior to the onset of 2,4-DCP mineralisation. Cumulative (CO2)-C-14 evolved after 21 days was significantly lower (p less than or equal to 0.05) from non-treated soil (25.3%) than re-inoculated soils (ca. 45%). Experiments investigating sorption-biodegradation interactions of xenobiotics in soil require the physico-chemical properties of sterile and non-sterile treatments to be as comparable as possible. For fundamental studies, we suggest using re-inoculated autoclaved soil as an additional or alternative non-sterile treatment. (C) 1999 Elsevier Science B.V.

Original languageEnglish
Pages (from-to)217-226
Number of pages10
JournalApplied Soil Ecology
Volume11
Publication statusPublished - 1999

Keywords

  • bioavailability
  • biodegradation
  • 2,4-dichlorophenol
  • sorption
  • sterilisation
  • ORGANIC-MATTER
  • GAMMA-IRRADIATION
  • ETHYLENE-OXIDE
  • FOREST SOILS
  • CARBON
  • STERILIZATION
  • ADSORPTION
  • BIOAVAILABILITY
  • MINERALIZATION
  • BACTERIA

Cite this

Shaw, L. J., Beaton, Y., Glover, L. A., Killham, K., & Meharg, A. A. (1999). Re-inoculation of autoclaved soil as a non-sterile treatment for xenobiotic sorption and biodegradation studies. Applied Soil Ecology, 11, 217-226.

Re-inoculation of autoclaved soil as a non-sterile treatment for xenobiotic sorption and biodegradation studies. / Shaw, L J ; Beaton, Y ; Glover, L A ; Killham, K ; Meharg, A A .

In: Applied Soil Ecology, Vol. 11, 1999, p. 217-226.

Research output: Contribution to journalArticle

Shaw, LJ, Beaton, Y, Glover, LA, Killham, K & Meharg, AA 1999, 'Re-inoculation of autoclaved soil as a non-sterile treatment for xenobiotic sorption and biodegradation studies' Applied Soil Ecology, vol. 11, pp. 217-226.
Shaw, L J ; Beaton, Y ; Glover, L A ; Killham, K ; Meharg, A A . / Re-inoculation of autoclaved soil as a non-sterile treatment for xenobiotic sorption and biodegradation studies. In: Applied Soil Ecology. 1999 ; Vol. 11. pp. 217-226.
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TY - JOUR

T1 - Re-inoculation of autoclaved soil as a non-sterile treatment for xenobiotic sorption and biodegradation studies

AU - Shaw, L J

AU - Beaton, Y

AU - Glover, L A

AU - Killham, K

AU - Meharg, A A

PY - 1999

Y1 - 1999

N2 - Autoclaved soil is commonly used for the study of xenobiotic sorption and as an abiotic control in biodegradation experiments. Autoclaving has been reported to alter soil physico-chemical and xenobiotic sorption characteristics such that comparison of autoclaved with non-autoclaved treatments in soil aging and bioavailability studies may yield misleading results. Experiments could be improved by using autoclaved soil re-inoculated with indigenous microorganisms as an additional or alternative non-sterile treatment for comparison with the sterile, autoclaved control. We examined the effect of autoclaving (3 x 1 h, 121 degrees C, 103.5 KPa) on the physico-chemical properties of a silt loam soil (pH 7.2, 2.3% organic carbon) and the establishment of indigenous microorganisms reintroduced after autoclaving. Sterilisation by autoclaving significantly (p less than or equal to 0.05) decreased pH (0.6 of a unit) and increased concentrations of water-soluble organic carbon (WSOC; nontreated = 75 mg kg(-1); autoclaved = 1526 mg kg(-1)). The initial first-order rate of C-14-2,4-dichloro-UL-phenol (2,4-DCP) adsorption to non-treated, autoclaved and re-inoculated soil was rapid (K-1 = 16.8-24.4 h(-1)) followed by a slower linear phase (K-2) In comparison with autoclaved soil (0.038% day(-1)), K-2 values were higher for re-inoculated (0.095% day(-1)) and nontreated (0.181% day(-1)) soil. This was attributed to a biological process. The Freundlich adsorption coefficient (K-t) for autoclaved soil was significantly (p less than or equal to 0.05) higher than for re-inoculated or non-treated soil, increased adsorption was attributed to autoclaving-induced changes to soil pH and solution composition. Glucose-induced respiration of autoclaved soil after re-inoculation was initially twice that in the non-treated control, but it decreased to control levels by day 4. This reduction corresponded to a depletion of WSOC. 2, I-DCP mineralisation experiments revealed that the inoculum of nonsterile soil (0.5 g) contained 2,4-DCP-degrading microorganisms capable of survival in autoclaved soil. The lag phase before detection of significant 2,4-DCP mineralisation was reduced (from 7 days to less than or equal to 3 days) by pre-incubation of re-inoculated soils for 7 and 14 days before 2,4-DCP addition. This was attributed to the preferential utilisation of WSOC prior to the onset of 2,4-DCP mineralisation. Cumulative (CO2)-C-14 evolved after 21 days was significantly lower (p less than or equal to 0.05) from non-treated soil (25.3%) than re-inoculated soils (ca. 45%). Experiments investigating sorption-biodegradation interactions of xenobiotics in soil require the physico-chemical properties of sterile and non-sterile treatments to be as comparable as possible. For fundamental studies, we suggest using re-inoculated autoclaved soil as an additional or alternative non-sterile treatment. (C) 1999 Elsevier Science B.V.

AB - Autoclaved soil is commonly used for the study of xenobiotic sorption and as an abiotic control in biodegradation experiments. Autoclaving has been reported to alter soil physico-chemical and xenobiotic sorption characteristics such that comparison of autoclaved with non-autoclaved treatments in soil aging and bioavailability studies may yield misleading results. Experiments could be improved by using autoclaved soil re-inoculated with indigenous microorganisms as an additional or alternative non-sterile treatment for comparison with the sterile, autoclaved control. We examined the effect of autoclaving (3 x 1 h, 121 degrees C, 103.5 KPa) on the physico-chemical properties of a silt loam soil (pH 7.2, 2.3% organic carbon) and the establishment of indigenous microorganisms reintroduced after autoclaving. Sterilisation by autoclaving significantly (p less than or equal to 0.05) decreased pH (0.6 of a unit) and increased concentrations of water-soluble organic carbon (WSOC; nontreated = 75 mg kg(-1); autoclaved = 1526 mg kg(-1)). The initial first-order rate of C-14-2,4-dichloro-UL-phenol (2,4-DCP) adsorption to non-treated, autoclaved and re-inoculated soil was rapid (K-1 = 16.8-24.4 h(-1)) followed by a slower linear phase (K-2) In comparison with autoclaved soil (0.038% day(-1)), K-2 values were higher for re-inoculated (0.095% day(-1)) and nontreated (0.181% day(-1)) soil. This was attributed to a biological process. The Freundlich adsorption coefficient (K-t) for autoclaved soil was significantly (p less than or equal to 0.05) higher than for re-inoculated or non-treated soil, increased adsorption was attributed to autoclaving-induced changes to soil pH and solution composition. Glucose-induced respiration of autoclaved soil after re-inoculation was initially twice that in the non-treated control, but it decreased to control levels by day 4. This reduction corresponded to a depletion of WSOC. 2, I-DCP mineralisation experiments revealed that the inoculum of nonsterile soil (0.5 g) contained 2,4-DCP-degrading microorganisms capable of survival in autoclaved soil. The lag phase before detection of significant 2,4-DCP mineralisation was reduced (from 7 days to less than or equal to 3 days) by pre-incubation of re-inoculated soils for 7 and 14 days before 2,4-DCP addition. This was attributed to the preferential utilisation of WSOC prior to the onset of 2,4-DCP mineralisation. Cumulative (CO2)-C-14 evolved after 21 days was significantly lower (p less than or equal to 0.05) from non-treated soil (25.3%) than re-inoculated soils (ca. 45%). Experiments investigating sorption-biodegradation interactions of xenobiotics in soil require the physico-chemical properties of sterile and non-sterile treatments to be as comparable as possible. For fundamental studies, we suggest using re-inoculated autoclaved soil as an additional or alternative non-sterile treatment. (C) 1999 Elsevier Science B.V.

KW - bioavailability

KW - biodegradation

KW - 2,4-dichlorophenol

KW - sorption

KW - sterilisation

KW - ORGANIC-MATTER

KW - GAMMA-IRRADIATION

KW - ETHYLENE-OXIDE

KW - FOREST SOILS

KW - CARBON

KW - STERILIZATION

KW - ADSORPTION

KW - BIOAVAILABILITY

KW - MINERALIZATION

KW - BACTERIA

M3 - Article

VL - 11

SP - 217

EP - 226

JO - Applied Soil Ecology

JF - Applied Soil Ecology

SN - 0929-1393

ER -