In vitro assessment of crude oil degradation by Acinetobacter junii and Alcanivorax xenomutans isolated from the coast of Ghana

Abstract

This study was aimed at using in vitro microcosm experiments to assess crude oil degradation efficiency of Acinetobacter junii and Alcanivorax xenomutans isolated along Ghana's coast. Uncontaminated seawater from selected locations along the coast was used to isolate bacterial species by employing enrichment culture procedures with crude oil as the only carbon source. The isolates were identified by means of the extended direct colony transfer method of the Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy (MALDI-TOF MS), as Acinetobacter junii, and Alcanivorax xenomutans. Remediation tests showed that Acinetobacter junii yielded degradation efficiencies of 27.59 %, 41.38 % and 57.47 %. Whereas efficiencies of 21.14 %, 32.18 % and 43.68 % were recorded by Alcanivorax xenomutans representing 15, 30 and 45 days respectively. Consortia of Acinetobacter junii, and Alcanivorax xenomutans also yielded 32.18 %, 48.28 % and 62.07 % for the selected days respectively. Phylogenetic characterization using ClustalW and BLAST of sequences generated from the Oxford Nanopore Sequencing technique, showed that the Ghanaian isolates clustered with Alcanivorax xenomutans and Acinetobacter junii species respectively. An analysis of the sequenced data for the 1394-bp portion of the 16S rRNA gene of the isolates revealed >99 % sequence identity with the isolates present on the GenBank database. The isolates of closest identity were Alcanivorax xenomutans and Acinetobacter junii with accession numbers, NR_133958.1 and KJ147060.1 respectively. Acinetobacter junii and Alcanivorax xenomutans isolated from Ghana's coast under pristine seawater conditions have therefore demonstrated their capacity to be used for the remediation of crude oil spills.