Characterization of an ibuprofen-eater bacteria

Camacho, Eva

Camacho, Eva · 2019

Abstract

The presence of pharmaceutical compounds (PhCs) in drinking water, treated wastewater, groundwater, surface water, and soil around the world is an emerging challenge. The bioremediation of organic pollutants by microbial degradation is a proven method for counteracting the contamination caused by these recalcitrant substances. We have isolated a bacterium belonging to the genus Sphingomonas, able to grow with ibuprofen as sole carbon and energy source. This strain was isolated from a Wastewater Treatment Plant of a pharmaceutical company (Almirall). Its genome sequence containes genes previously described as necessary for the biotransformation of ibuprofen. The ipf cluster is flanked by tranposon sequences and its GC content is lower than the average of the genome, suggesting that this cluster could have been horizontally acquired. We performed a transposon mutagenesis with a miniTn5 derivatives and selected mutants unable to use ibuprofen as a nutrient. Three different phenotypes were detected: (i) mutants unable to grow that do not modify the growth medium, (ii) mutants unable to grow that give a brown colour to the medium and (iii) leaky mutants able to poorly grow on ibuprofen. Sequencing of the region flanking the insertions mapped the insertions as follows: the non-coloured mutants (i) were mainly located into the ipf cluster, the brown mutants (ii) in a different genomic region that contains genes belonging to aromatics degradation pathway and the leaky mutants (iii) in a Propionyl-CoA carboxylase carboxyl transferase subunit. We have constructed a genomic library to complement those mutant and the results suggest that only these regions are involved in ibuprofen degradation. We propose a complete ibuprofen degradation pathway that seems to have been formed by combination of different biodegradation pathways, some of which acquired by horizontal gene transfer.

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Characterization of an ibuprofen-eater bacteria

Author: Camacho, Eva

Year: 2019

Source: https://riuma.uma.es/xmlui/bitstream/10630/18428/1/Cartel%20Eva%20RIUMA.pdf

Cha ac e iza ion,o ,an,ibup o en-ea e ,bac e ia,
E a,Camacho,(Uni e sidad,Pablo,de,Ola ide),
The$ p esence$ o $ pha maceu ical$ compounds$ (PhCs)$ in$ d inking$ wa e ,$ ea ed$
was ewa e ,$g oundwa e ,$su ace$wa e ,$and$soil$a ound$ he$wo ld$is$an$eme ging$
challenge.$The$bio emedia ion$o $o ganic$pollu an s$by$mic obial$deg ada ion$is$a$
p o en$me hod$ o $coun e ac ing$ he$con amina ion$caused$by$ hese$ ecalci an $
subs ances.$
We$ha e$isola ed$a$bac e ium$belonging$ o$ he$genus$Sphingomonas,$able$ o$g ow$
wi h$ibup o en$as$sole$ca bon$and$ene gy$sou ce.$This$s ain$was$isola ed$ om$a$
Was ewa e $T ea men $Plan $o $a$pha maceu ical$company$(Almi all).$I s$genome$
sequence$ con aines$genes$ p e iously$ desc ibed$ as$ necessa y$ o $ he$
bio ans o ma ion$o $ibup o en.$The$ip $clus e $is$ lanked$by$ anposon$sequences$
and$i s$GC$con en $is$lowe $ han$ he$a e age$o $ he$genome,$sugges ing$ ha $ his$
clus e $could$ha e$been$ho izon ally$acqui ed.$
We$pe o med$a$ ansposon$mu agenesis$wi h$a$miniTn5$de i a i es$and$selec ed$
mu an s$unable$ o$use$ibup o en$as$a$ nu ien .$ Th ee$di e en $pheno ypes$we e$
de ec ed:$(i)$mu an s$unable$ o$g ow$ ha $do$no $modi y$ he$g ow h$medium,$(ii)$
mu an s$ unable$ o$ g ow$ ha $ gi e$ a$ b own$ colou $ o$ he$ medium$ and$ (iii)$ leaky$
mu an s$able$ o$poo ly$g ow$on$ibup o en.$Sequencing$o $ he$ egion$ lanking$ he$
inse ions$ mapped$ he$ inse ions$ as$ ollows:$ he$ non-colou ed$ mu an s$ (i)$ we e$
mainly$loca ed$in o$ he$ip $clus e ,$ he$b own$mu an s$(ii)$in$a$di e en $genomic$
egion$ ha $ con ains$ genes$ belonging$ o$ a oma ics$ deg ada ion$ pa hway$ and$ he$
leaky$ mu an s$ (iii)$ in$ a$ P opionyl-CoA$ ca boxylase$ ca boxyl$ ans e ase$ subuni .$
We$ ha e$ cons uc ed$ a$ genomic$ lib a y$ o$ complemen $ hose$ mu an $ and$ he$
esul s$sugges $ ha $only$ hese$ egions$a e$in ol ed$in$ibup o en$deg ada ion.$
We$p opose$a$comple e$ibup o en$deg ada ion$pa hway$ ha $seems$ o$ha e$been$
o med$ by$ combina ion$ o $ di e en $ biodeg ada ion$ pa hways,$ some$ o $ which$
acqui ed$by$ho izon al$gene$ ans e .$
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