Hydrocarbon degrading microbial communities in bench scale aerobic biobarriers for gasoline contaminated groundwater treatment.
BTEX compounds (benzene, toluene, ethylbenzene and xylenes) and methyl tert-butyl ether (MTBE) are some of the main constituents of gasoline and can be accidentally released in the environment. In this work the effect of bioaugmentation on the microbial communities in a bench scale aerobic biobarrier for gasoline contaminated water treatment was studied by 16S rRNA gene sequencing. Catabolic genes (tmoA and xylM) were quantified by qPCR, in order to estimate the biodegradation potential, and the abundance of total bacteria was estimated by the quantification of the number of copies of the 16S rRNA gene. Hydrocarbon concentration was monitored over time and no difference in the removal efficiency for the tested conditions was observed, either with or without the microbial inoculum. In the column without the inoculum the most abundant genera were Acidovorax, Bdellovibrio, Hydrogenophaga, Pseudoxanthomonas and Serpens at the beginning of the column, while at the end of the column Thauera became dominant. In the inoculated test the microbial inoculum, composed by Rhodococcus sp. CE461, Rhodococcus sp. CT451 and Methylibium petroleiphilum LMG 22953, was outcompeted. Quantitative PCR results showed an increasing in xylM copy number, indicating that hydrocarbon degrading bacteria were selected during the treatment, although only a low increase of the total biomass was observed. However, the bioaugmentation did not lead to an increase in the degradative potential of the microbial communities.
Dept. of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy.
Matteo
M
Daghio
Dept. of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy.
Valeria
V
Tatangelo
Dept. of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy. Electronic address: andrea.franzetti@unimib.it.
Andrea
A
Franzetti
Dept. of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy.
Isabella
I
Gandolfi
INAIL Settore Ricerca, Certificazione e Verifica, DIPIA, Rome, Italy.
Maddalena
M
Papacchini
Politecnico di Milano, DICA Sez. Ambientale, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
Alessandro
A
Careghini
Politecnico di Milano, DICA Sez. Ambientale, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
Elena
E
Sezenna
Politecnico di Milano, DICA Sez. Ambientale, Piazza Leonardo da Vinci 32, 20133 Milan, Italy.
Sabrina
S
Saponaro
Dept. of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy.
Giuseppina
G
Bestetti
D001554:Benzene / Q000032:analysis; D001673:Biodegradation, Environmental; D005742:Gasoline / Q000032:analysis*; D060587:Groundwater / Q000032:analysis*; D006838:Hydrocarbons / Q000378:metabolism*; D008837:Micrococcus / Q000235:genetics / Q000378:metabolism; D025341:Principal Component Analysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012240:Rhodococcus / Q000235:genetics / Q000378:metabolism; D014050:Toluene / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000379:methods; D014992:Xylenes / Q000032:analysis
D005742:Gasoline; D006838:Hydrocarbons; D012336:RNA, Ribosomal, 16S; D014874:Water Pollutants, Chemical; D014992:Xylenes; D014050:Toluene; D001554:Benzene
BTEX; Bioremediation; Illumina sequencing; qPCR