From oil spills to barley growth – oil‐degrading soil bacteria and their promoting effects

Abstract

Heavy contamination of soils by crude oil is omnipresent in areas of oil recovery and exploitation. Bioremediation by indigenous plants in cooperation with hydrocarbon degrading microorganisms is an economically and ecologically feasible means to reclaim contaminated soils. To study the effects of indigenous soil bacteria capable of utilizing oil hydrocarbons on biomass production of plants growing in oil-contaminated soils eight bacterial strains were isolated from contaminated soils in Kazakhstan and characterized for their abilities to degrade oil components. Four of them, identified as species of Gordonia and Rhodococcus turned out to be effective degraders. They produced a variety of organic acids from oil components, of which 59 were identified and 7 of them are hitherto unknown acidic oil metabolites. One of them, Rhodococcus erythropolis SBUG 2054, utilized more than 140 oil components. Inoculating barley seeds together with different combinations of these bacterial strains restored normal growth of the plants on contaminated soils, demonstrating the power of this approach for bioremediation. Furthermore, we suggest that the plant promoting effect of these bacteria is not only due to the elimination of toxic oil hydrocarbons but possibly also to the accumulation of a variety of organic acids which modulate the barley's rhizosphere environment.

Moniliella spathulata, an oil-degrading yeast, which promotes growth of barley in oil-polluted soil

“…More than 51 aliphatic and aromatic acids were formed during the degradation of the oil components (Table 2). Thus, this study establishes that yeasts can have oil-degrading properties comparable to those of bacteria (Mikolasch et al 2015;Mikolasch et al 2016), which was also described for yeast strains of the genera Candida and Trichosporon (Farag and Soliman 2011;Gargouri et al 2015). Proteome analyses of M. spathulata showed expression of nearly all potential enzymes necessary for the degradation of alkanes and alkyl chains of cycloaliphatic compounds via initial hydroxylation, transformation to acids, and β-oxidation: monooxygenase (moo), alcohol dehydrogenase (alcd), aldehyde dehydrogenase (aldd), acyl-CoA dehydrogenase (aCd), alpha-beta-hydrolase (abh), 3hydroxyacyl-CoA dehydrogenase (3OHaCd), and thiolase (thio) (Fig.…”

“…The P(T<-t) values support the hypothesis of significant growth increase by the inoculation of seeds with M. spathulata SBUG-Y 2180 in oil-containing sand. The inoculation of barley with bacteria of the genera Gordonia and Rhodococcus or the inoculation with culture mixtures of the genera Rhodococcus and Bacillus or Rhodococcus and Sphingobacterium promoted the growth of barley in the same way as M. spathulata SBUG-Y 2180 (Mikolasch et al 2015;Mikolasch et al 2016), in which the effects to the shoot Fig. 4 Proposed diterminal oxidation pathway for the degradation of pristane and phytane by M. spathulata SBUG-Y 2180 (detailed structural characterization of pristane metabolites in Supplementary Table S15).…”

“…This work is dedicated to the late scientist Frieder Schauer. exchange metabolites and end products between each other and with plants in the neighborhood (Ivanova et al 2015;Kuiper et al 2004;Mikolasch et al 2016).…”

Isolation and Screening of Biosurfactant-Producing Marine Bacteria From Kuantan Port, Pahang, Malaysia

“…Several studies done by a number of researchers agreed that Pseudomonas sp. was a common hydrocarbon degrading bacteria and able to degrade xenobiotic and more than 100 organic compounds due to the wide diversity of complex enzymatic system present within this genus [7,19,26]. The bacteria obtained from NCBI were isolated from the sea, sea sediment and water environment which made the finding to have a strong basis.…”

Bacterial crude oil and polyaromatic hydrocarbon degraders from Kazakh oil fields as barley growth support

“…For this purpose, we have isolated and taxonomically classified microorganisms from contaminated soil samples in Kazakhstan. We then investigated their catabolic potential and assessed their suitability for use in remediation projects (Mikolasch et al 2020 , 2019 , 2015 , 2016 ). Bacteria and fungi are the main groups of soil microbes that play crucial roles in the biodegradation of hydrocarbons in oil-contaminated soils (Cabral et al 2022 ; Espinosa-Ortiz et al 2022 ; Mahjoubi et al 2013 ; Quatrini et al 2008 ; Silva et al 2015 ).…”