Bacterial Isolates from Greek Sites and Their Efficacy in Degrading Petroleum

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are a major organic pollutant, not only because they do not self-degenerate but also because they accumulate in the food chain and give rise to serious repercussions in terms of biodiversity sustainability. Petroleum-degrading bacteria have long been used as a promising solution in the effort to biodegrade crude oil. In this study, new isolates from specific Greek environments displaying various levels of crude oil contamination, as well as isolates belonging to the ATHUBA collection, were thoroughly investigated for their capacity to degrade crude oil. Furthermore, the presence of nahH and alkJ genes in the above bacterial isolates, as well as their ability to form agglomerates or release surfactants, was investigated. Two consortia were formed, and their ability to degrade crude oil was tested, achieving similar degrading capacities as those observed with the individual strains. A Pseudomonas plecoglossicida isolate demonstrated the highest percentage (76.7%) ability to degrade crude oil. The biodegradation rate of this isolate was further evaluated by measuring the alkanes/hopanes ratio over a period of ten days, exhibiting a higher degradation rate in short-chain (C11–C21) alkanes, whereas a decrease in the ratio was observed when the number of carbons in petroleum increased. This is the first detailed report on bacterial communities in oil-polluted areas of Greece that contain a variety of bacteria with the ability to degrade PAHs in contaminated sites and may provide a novel alternative to various bioremediation processes or be used as inocula in autochthonous bioaugmentation procedures for crude oil biodegradation.

Current Trends in Bioaugmentation Tools for Bioremediation: A Critical Review of Advances and Knowledge Gaps

“…The application of a consortium resulted in the highest PCB-209 removal potential [ 29 ]. Another study showed that consortia and individual strains had similar crude oil-degrading capacities [ 11 ]. Moreover, [ 37 ] reported that the oil biodegradation efficiency of single strains and consortia ( Actinotalea ferrariae , Arthrobacter ginsengisoli , Dietzia cinnamea , Dietzia papillomatosis , and Pseudomonas songnenensis ) was similar, and that the REs of bioaugmented and non-bioaugmented sets in an oil-saturated desert soil after a 6-month experiment were also similar, exhibiting similar predominant bacterial species, e.g., Ar.…”

“…Bioaugmentation is a site-specific approach. Thus, recent research publications and reviews on bioaugmentation have focused on the following aspects: thermophilic reductive dechlorination [ 4 , 5 ]; the psychrophilic treatment of groundwaters [ 6 ]; microbially induced calcium carbonate precipitation techniques to mitigate the wind-induced erosion of calcareous desert sand [ 7 ]; hydrocarbon biodegradation in freshwater sediments from historically contaminated lakes [ 8 ]; the bacterial remediation of pesticide-polluted soils [ 3 ], emerging trends in the remediation of organic contaminated soils as a whole [ 9 ]; mechanisms of microbial activity in heavy metal removal [ 10 ]; comparisons of autochthonous and allochthonous bioaugmentation [ 11 ]; the stimulation of plant growth in bioaugmented hydroponic systems [ 12 ]; and the bioaugmentation of wastewaters (WWs) with yeast in the presence of antimicrobials [ 13 ], among others.…”