Jens Aamand | GEUS Geological Survey of Denmark and Greenland (original) (raw)

Papers by Jens Aamand

Benzophenone-3 (BP3) is an organic UV filter whose presence in the aquatic environment has been l... more Benzophenone-3 (BP3) is an organic UV filter whose presence in the aquatic environment has been linked to detrimental developmental impacts in aquatic organisms such as coral and fish. The genus Rhodococcus has been extensively studied and is known for possessing large genomes housing genes for biodegradation of a wide range of compounds, including aromatic carbons. Here, we present the genome sequence of Rhodococcus sp. USK10, which was isolated from Chinese riverbank sediment and is capable of utilising BP3 as the sole carbon source, resulting in full BP3 mineralisation. The genome consisted of 9,870,030 bp in 3 replicons, a G+C content of 67.2%, and 9,722 coding DNA sequences (CDSs). Annotation of the genome revealed that 179 of these CDSs are involved in metabolism of aromatic carbons. The complete genome of Rhodococcus sp. USK10 is the first complete, annotated genome sequence of a Benzophenone-3 degrading bacterium. Through radiolabelling, it is also the first bacterium proven...

Applied and Environmental Microbiology, 1991

We studied the degradation of pentachlorophenol (PCP) under methanogenic and sulfate-reducing con... more We studied the degradation of pentachlorophenol (PCP) under methanogenic and sulfate-reducing conditions with an anaerobic mixed culture derived from sewage sludge. The consortium degraded PCP via 2,3,4,5-tetrachlorophenol, 3,4,5-trichlorophenol, and 3,5-dichlorophenol and eventually accumulated 3-chlorophenol. Dechlorination of PCP and metabolites was inhibited in the presence of sulfate, thiosulfate, and sulfite. A decrease in the rate of PCP transformation was noted when the endogenous dissolved H 2 was depleted below 0.11 μM in sulfate-reducing cultures. The effect on dechlorination observed with sulfate could be relieved by addition of molybdate, a competitive inhibitor of sulfate reduction. Addition of H 2 reduced the inhibition observed with sulfuroxy anions. The inhibitory effect of sulfuroxy anions may be due to a competition for H 2 between sulfate reduction and dechlorination. When cultured under methanogenic conditions, the consortium degraded several chlorinated and bro...

As one of the only described degraders of the recalcitrant metabolite 2,6-dichlorobenzamide (BAM)... more As one of the only described degraders of the recalcitrant metabolite 2,6-dichlorobenzamide (BAM) of the pesticide dichlobenil, Aminobacter sp. MSH1 has been intensively studied for its characteristics with regards to physiology and its use in bioremediation. Two plasmid sequences from strain MSH1 have previously been published, while the remaining genome sequence has been left uninvestigated. We here present the complete genome sequence of this important strain, which consists of a chromosome, two megaplasmids and five smaller plasmids. Intriguingly, the plasmid copy numbers are mostly below one per bacterial chromosome, indicating that plasmids in strain MSH1 are under very unstable conservation. The results of this report improve our understanding of the genomic dynamics of Aminobacter sp. MSH1.

AMB Express, 2016

Pesticides are used extensively worldwide, which has led to the unwanted contamination of soil an... more Pesticides are used extensively worldwide, which has led to the unwanted contamination of soil and water resources. Former use of the herbicide 2,6-dichlorobenzonitrile (dichlobenil) has caused pollution of ground and surface water resources by the stable degradation product 2,6-dichlorobenzamide (BAM) in several parts of Europe, which has resulted in the costly closure of several drinking water wells. One strategy for preventing this in future is bioaugmentation using bacterial degraders. BAM-degrading Aminobacter sp. MSH1 was therefore formulated into dried beads and tests undertaken to establish their potential for use in the remediation of polluted soil, sand and water. The formulation procedure included freeze drying, combined with trehalose addition for cell wall protection, thus ensuring a high amount of viable cells following prolonged storage at room temperature. The beads were round-shaped pellets with a diameter of about 1.25 mm, a dry matter content of approximately 95 %...

The degradation of pesticides in deeper soil layers and groundwater is of growing interest, becau... more The degradation of pesticides in deeper soil layers and groundwater is of growing interest, because they have repeatedly been found in drinking water supply wells and may pose a risk to future water resources. Current assessment schemes face a common problem, however: natural degradation often cannot be reliably assessed by concentration measurements alone, since mass balances are difficult to establish

Journal of Contaminant Hydrology, 1989

ABSTRACT

Biodegradation, 2001

Degradation of the phenylurea herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) and ... more Degradation of the phenylurea herbicide isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) and several phenylurea and aniline metabolites was studied in agricultural soils previously exposed to isoproturon. The potential for degradation of the demethylated metabolite 3-(4-isopropylphenyl)-1-methylurea in the soils was much higher compared to isoproturon. In the most active soil only 6% of added 14C-labelled isoproturon was mineralised to 14C2 within 20 days while in the same period 45% of added 14C-labelled 3-(4-isopropylphenyl)-1-methylurea was mineralized. This indicates that the initial N-demethylation may be a limiting step in the complete mineralization of isoproturon. Repeated addition of 3-(4-isopropylphenyl)-1-methylurea to the soil and further subculturing in mineral medium led to a highly enriched mixed bacterial culture with the ability to mineralize 3-(4-isopropylphenyl)-1-methylurea.The culture did not degrade either isoproturon or the didemethylatedmetabolite 3-(4-is...

FEMS Microbiology Ecology, 2014

FEMS Microbiology Ecology, 2002

Environmental Science & Technology, 2012

Environmental Pollution, 2011

Applied and Environmental Microbiology, 2005

Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be abl... more Several asco-, basidio-, and zygomycetes isolated from an agricultural field were shown to be able to hydroxylate the phenylurea herbicide isoproturon [ N -(4-isopropylphenyl)- N ′, N ′-dimethylurea] to N -(4-(2-hydroxy-1-methylethyl)phenyl)- N ′, N ′ - dimethylurea and N -(4-(1-hydroxy-1-methylethyl)phenyl)- N ′, N ′-dimethylurea. Bacterial metabolism of isoproturon has previously been shown to proceed by an initial demethylation to N -(4-isopropylphenyl)- N ′-methylurea. In soils, however, hydroxylated metabolites have also been detected. In this study we identified fungi as organisms that potentially play a major role in the formation of these hydroxylated metabolites in soils treated with isoproturon. Isolates of Mortierella sp. strain Gr4, Phoma cf. eupyrena Gr61, and Alternaria sp. strain Gr174 hydroxylated isoproturon at the first position of the isopropyl side chain, yielding N -(4-(2-hydroxy-1-methylethyl)phenyl)- N ′, N ′ - dimethylurea, while Mucor sp. strain Gr22 hydroxy...

Environmental Pollution, 2013

To understand the role of abundance of tfdA gene classes belonging to β- and γ-proteobacteria on ... more To understand the role of abundance of tfdA gene classes belonging to β- and γ-proteobacteria on phenoxy acid herbicide degradation, streambed sediments were sampled around three seepage meters (SMs) installed in a landfill-impacted groundwater-surface water interface. Highest herbicide mass discharge to SM3, and lower herbicide mass discharges to SM1 and SM2 were determined due to groundwater discharge rates and herbicide concentrations. SM1-sediment with the lowest abundance of tfdA gene classes had the slowest mineralization, whereas SM2- and SM3-sediments with more abundant tfdA genes had faster mineralization. The observed difference in mineralization rates between discharge zones was simulated by a Monod-based kinetic model, which confirmed the role of abundance of tfdA gene classes. This study suggests presence of specific degraders adapted to slow growth rate and high yield strategy due to long-term herbicide exposure; and thus groundwater-surface water interface could act as a natural biological filter and protect stream water quality.

Geological Survey of Denmark and Greenland Bulletin, 2004

Groundwater is the major source of drinking water in many European countries, and in Denmark alon... more Groundwater is the major source of drinking water in many European countries, and in Denmark alone it accounts for more than 99% of the drinking water supply. Within the past decade pesticide residues have frequently been detected in groundwater, in many cases at levels exceeding the 0.1 µg/l limit set by the European Community. As a consequence, drinking water abstraction wells have had to be closed in many places in Denmark and other European countries, and a vast amount of money is expended to monitor groundwater pesticide levels. A degradation product of the herbicide dichlobenil, 2,6-dichlorobenzamide (BAM), is the most common cause of drinking water well closure in Denmark. Triazines and their metabolites also contaminate groundwater in many countries, and pose a similar risk to the drinking water supply. Analysis of most pesticides and their degradation products is usually carried out by concentrating the samples by solvent extraction, and identifying the contaminants using g...

Applied and environmental microbiology, Jan 20, 2015

In this study, we investigated the establishment of natural bacterial degraders in a sand filter ... more In this study, we investigated the establishment of natural bacterial degraders in a sand filter treating groundwater contaminated with the phenoxypropionate herbicides MCPP and DCPP and the associated impurity/catabolite 4-CPP. A pilot facility was set up in a contaminated landfill-site. Anaerobic groundwater was pumped up and passed through an aeration basin and subsequently through a rapid sand filter, which is characterized by a low residence time of the water in the filter. During three months, degradation of DCPP, MCPP and 4-CPP in the sand filter increased to 15-30% of the inlet concentration. A significant selection for natural bacterial herbicide degraders also occurred in the sand filter. Using a Most Probable Number (MPN) method, we found a steady increase in the number of culturable phenoxypropionate degraders, reaching approximately 5×10(5) degraders per g sand, by the end of the study. Using qPCR targeting the two phenoxypropionate degradation genes rdpA and sdpA encod...