2,6-Dichlorobenzamide (BAM) herbicide mineralisation by Aminobacter sp. MSH1 during starvation depends on a subpopulation of intact cells maintaining vital membrane functions

TY - JOUR

T1 - 2,6-Dichlorobenzamide (BAM) herbicide mineralisation by Aminobacter sp. MSH1 during starvation depends on a subpopulation of intact cells maintaining vital membrane functions

AU - Sjøholm, Ole Rüdiger

AU - Nybroe, Ole

AU - Aamand, Jens

AU - Sørensen, Jan

PY - 2010/12

Y1 - 2010/12

N2 - Mineralisation capability was studied in the 2,6-dichlorobenzamide (BAM)-degrading Aminobacter sp. MSH1 under growth-arrested conditions. Cells were starved in mineral salts (MS) solution or groundwater before 14C-labelled BAM (0.1 mM) was added. Cell physiology was monitored with a panel of vitality stains combined with flow cytometry to differentiate intact, depolarised and dead cells. Cells starved for up to 3 weeks in MS solution showed immediate growth-linked mineralisation after BAM amendment while a lag-phase was seen after 8 weeks of starvation. In contrast, cells amended with BAM in natural groundwater showed BAM mineralisation but no growth. The cell-specific mineralisation rate was always comparable (10-16 mol C intact cell-1 day-1) independent of media, growth, or starvation period after BAM amendment; lower rates were only observed as BAM concentration decreased. MSH1 seems useful for bioremediation and should be optimised to maintain an intact cell subpopulation as this seems to be the key parameter for successful mineralisation.

AB - Mineralisation capability was studied in the 2,6-dichlorobenzamide (BAM)-degrading Aminobacter sp. MSH1 under growth-arrested conditions. Cells were starved in mineral salts (MS) solution or groundwater before 14C-labelled BAM (0.1 mM) was added. Cell physiology was monitored with a panel of vitality stains combined with flow cytometry to differentiate intact, depolarised and dead cells. Cells starved for up to 3 weeks in MS solution showed immediate growth-linked mineralisation after BAM amendment while a lag-phase was seen after 8 weeks of starvation. In contrast, cells amended with BAM in natural groundwater showed BAM mineralisation but no growth. The cell-specific mineralisation rate was always comparable (10-16 mol C intact cell-1 day-1) independent of media, growth, or starvation period after BAM amendment; lower rates were only observed as BAM concentration decreased. MSH1 seems useful for bioremediation and should be optimised to maintain an intact cell subpopulation as this seems to be the key parameter for successful mineralisation.

KW - BRIC

KW - Mineralisation

KW - 2,6-Dichlorobenzamide

KW - Groundwater

KW - Flow cytometry

KW - Single-cell activity

U2 - 10.1016/j.envpol.2010.08.006

DO - 10.1016/j.envpol.2010.08.006

M3 - Journal article

SN - 0269-7491

VL - 158

SP - 3618

EP - 3625

JO - Environmental Pollution

JF - Environmental Pollution

IS - 12

ER -