title: Olive-pomace harbors bacteria with the potential for hydrocarbon-biodegradation, nitrogen-fixation and mercury-resistance: promising material for waste-oil-bioremediation.
abstract: Olive-pomace, a waste by-product of olive oil industry, took up >40% of its weight crude oil. Meanwhile, this material harbored a rich and diverse hydrocarbonoclastic bacterial population in the magnitude of 10(6) to 10(7) cells g(-1). Using this material for bioaugmentation of batch cultures in crude oil-containing mineral medium, resulted in the consumption of 12.9, 21.5, 28.3, and 43% oil after 2, 4, 6 and 8 months, respectively. Similar oil-consumption values, namely 11.0, 29.3, 34.7 and 43.9%, respectively, were recorded when a NaNO3-free medium was used instead of the complete medium. Hydrocarbonoclastic bacteria involved in those bioremediation processes, as characterized by their 16S rRNA-gene sequences, belonged to the genera Agrococcus, Pseudomonas, Cellulosimicrobium, Streptococcus, Sinorhizobium, Olivibacter, Ochrobactrum, Rhizobium, Pleomorphomonas, Azoarcus, Starkeya and others. Many of the bacterial species belonging to those genera were diazotrophic; they proved to contain the nifH-genes in their genomes. Still other bacterial species could tolerate the heavy metal mercury. The dynamic changes of the proportions of various species during 8 months of incubation were recorded. The culture-independent, phylogenetic analysis of the bacterioflora gave lists different from those recorded by the culture-dependent method. Nevertheless, those lists comprised among others, several genera known for their hydrocarbonoclastic potential, e.g. Pseudomonas, Mycobacterium, Sphingobium, and Citrobacter. It was concluded that olive-pomace could be applied in oil-remediation, not only as a physical sorbent, but also for bioaugmentation purposes as a biological source of hydrocarbonoclastic bacteria.
authors.affiliation: Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
authors.forename: Narjes
authors.initials: N
authors.lastname: Dashti
authors.affiliation: Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
authors.forename: Nedaa
authors.initials: N
authors.lastname: Ali
authors.affiliation: Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
authors.forename: Majida
authors.initials: M
authors.lastname: Khanafer
authors.affiliation: Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
authors.forename: Husain
authors.initials: H
authors.lastname: Al-Awadhi
authors.affiliation: Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait.
authors.forename: Naser
authors.initials: N
authors.lastname: Sorkhoh
authors.affiliation: Department of Biological Sciences, Faculty of Science, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait. Electronic address: samir.radwan@ku.edu.kw.
authors.forename: Samir
authors.initials: S
authors.lastname: Radwan
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D001673:Biodegradation, Environmental; D006801:Humans; D007220:Industrial Waste / Q000517:prevention & control; D009586:Nitrogen Fixation; D000069463:Olive Oil; D010578:Petroleum / Q000378:metabolism*; D059392:Petroleum Pollution; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D007220:Industrial Waste; D000069463:Olive Oil; D010578:Petroleum; D012336:RNA, Ribosomal, 16S
keywords: Bioaugmentation; Oil-bioremediation; Olive-pomace; Sorbents