Efficiency and kinetics of Assam crude oil degradation by Pseudomonas aeruginosa and Bacillus sp

Enrichment of microbial consortia for MEOR in crude oil phase of reservoir-produced liquid and their response to environmental disturbance

Developing microbial consortiums is necessary for microbial enhanced oil recovery (MEOR) in heavy crude oil production. The aqueous phase of produced fluid has long been considered an ideal source of microorganisms for MEOR. However, it is recently found that rich microorganisms (including hydrocarbon-degrading bacteria) are present in the crude oil phase, which is completely different from the aqueous phase of produced fluid. So, in this study, the microbial consortia from the crude oil phase of produced fluids derived from four wells were enriched, respectively. The microbial community structure during passage was dynamically tracked, and the response of enriched consortia to successive disturbance of environmental factors was investigated. The results showed the crude oil phase had high microbial diversity, and the original microbial community structure from four wells was significantly different. After ten generations of consecutive enrichment, different genera were observed in the four enriched microbial consortia, namely, Geobacillus, Bacillus, Brevibacillus, Chelativorans, Ureibacillus, and Ornithinicoccus. In addition, two enriched consortia (eG1614 and eP30) exhibited robustness to temperature and oxygen perturbations. These results further suggested that the crude oil phase of produced fluids can serve as a potential microbial source for MEOR.

Characterization of Diesel Degrading Indigenous Bacterial Strains, Acinetobacter pittii and Pseudomonas aeruginosa, Isolated from Oil Contaminated Soils

In this study, 13 diesel degrading bacteria were isolated from the oil contaminated soils and the promising strains identified as Acinetobacter pittii ED1 and Pseudomonas aeruginosa BN were evaluated for their diesel degrading capabilities. These strains degraded the diesel optimally at 30 °C, pH 7.0 and 1% diesel concentration. Both the strains produced biofilm at 1% diesel concentration indicating their ability to tolerate diesel induced abiotic stress. Gravimetric analysis of the spent medium after 7 days of incubation showed that A. pittii ED1 and P. aeruginosa BN degraded 68.61% and 76% diesel, respectively, while biodegradation reached more than 90% after 21 days. Fourier Transform Infrared (FTIR) analysis of the degraded diesel showed 1636.67 cm-1 (C=C stretch, N-H bond) peak corresponding to alkenes and primary amines, while GC-TOF-MS analysis showed decline in hydrocarbon intensities after 7 days of incubation. The present study revealed that newly isolated A. pittii ED1 and P. aeruginosa BN were able to degrade diesel hydrocarbons (C11-C18, and C19-C24) efficiently and have potential for bioremediation of the oil-contaminated sites.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-024-01317-3.

Construction of yeast microbial consortia for petroleum hydrocarbons degradation

Microbial degradation of petroleum hydrocarbons plays a vital role in mitigating petroleum contamination and heavy oil extraction. In this study, a Saccharomyces cerevisiae capable of degrading hexadecane has been successfully engineered, achieving a maximum degradation rate of up to 20.42%. However, the degradation ability of this strain decreased under various pressure conditions such as high temperature, high osmotic pressure, and acidity conditions. Therefore, a S. cerevisiae with high tolerance to these conditions has been constructed. And then, we constructed an "anti-stress hydrocarbon-degrading" consortium comprising engineered yeast strain SAH03, which degrades hexadecane, and glutathione synthetic yeast YGSH10, which provides stress resistance. This consortium was able to restore the degradation ability of SAH03 under various pressure conditions, particularly exhibiting a significant increase in degradation rate from 5.04% to 17.04% under high osmotic pressure. This study offers a novel approach for improving microbial degradation of petroleum hydrocarbons.

Bioremediation of environmental organic pollutants by Pseudomonas aeruginosa: Mechanisms, methods and challenges

The development of the chemical industry has led to a boom in daily consumption and convenience, but has also led to the release of large amounts of organic pollutants, such as petroleum hydrocarbons, plastics, pesticides, and dyes. These pollutants are often recalcitrant to degradation in the environment, whereby the most problematic compounds may even lead to carcinogenesis, teratogenesis and mutagenesis in animals and humans after accumulation in the food chain. Microbial degradation of organic pollutants is efficient and environmentally friendly, which is why it is considered an ideal method. Numerous studies have shown that Pseudomonas aeruginosa is a powerful platform for the remediation of environmental pollution with organic chemicals due to its diverse metabolic networks and its ability to secrete biosurfactants to make hydrophobic substrates more bioavailable, thereby facilitating degradation. In this paper, the mechanisms and methods of the bioremediation of environmental organic pollutants (EOPs) by P. aeruginosa are reviewed. The challenges of current studies are highlighted, and new strategies for future research are prospected. Metabolic pathways and critical enzymes must be further deciphered, which is significant for the construction of a bioremediation platform based on this powerful organism.

Taxonomic and Predictive Functional Profile of Hydrocarbonoclastic Bacterial Consortia Developed at Three Different Temperatures

Microbial community exhibit shift in composition in response to temperature variation. We report crude oil-degrading activity and high-throughput 16S rRNA gene sequencing (metagenome) profiles of four bacterial consortia enriched at three different temperatures in crude oil-amended Bushnell-Hass Medium from an oily sludge sediment. The consortia were referred to as O (4 ± 2 ℃ in 3% w/v crude oil), A (25 ± 2 ℃ in 1% w/v crude oil), H (25 ± 2 ℃ in 3% w/v crude oil), and X (45 ± 2 ℃ in 3% w/v crude oil). The hydrocarbon-degrading activity was highest for consortium A and H and lowest for consortium O. The metagenome profile revealed the predominance of Proteobacteria (62.12-1.25%) in each consortium, followed by Bacteroidota (18.94-37.77%) in the consortium O, A, and H. Contrarily, consortium X comprised 7.38% Actinomycetota, which was essentially low (< 0.09%) in other consortia, and only 0.41% Bacteroidota. The PICRUSt-based functional analysis predicted major functions associated with the metabolism and 5060 common KEGG Orthology (KOs). A total of 296 KOs were predicted exclusively in consortium X. Additionally, 247 KOs were predicted from xenobiotic biodegradation pathways. This study found that temperature had a stronger influence on the composition and function of the bacterial community than crude oil concentration.

Current trends in bioremediation and bio-integrated treatment of petroleum hydrocarbons

Petroleum hydrocarbons and their derivatives constitute the leading group of environmental pollutants worldwide. In the present global scenario, petroleum and natural gas production, exploration, petroleum refining, and other anthropogenic activities produce huge amounts of hazardous petroleum wastes that accumulate in the terrestrial and marine environment. Due to their carcinogenic, neurotoxic, and mutagenic characteristics, petroleum pollutants pose severe risks to human health and exert ecotoxicological effects on the ecosystems. To mitigate petroleum hydrocarbons (PHs) contamination, implementing "green technologies" for effective cleanup and restoration of an affected environment is considered as a pragmatic approach. This review provides a comprehensive outline of newly emerging bioremediation technologies, for instance; nanobioremediation, electrokinetic bioremediation, vermiremediation, multifunctional and sustainably implemented on-site applied biotechnologies such as; natural attenuation, biostimulation, bioaugmentation, bioventing, phytoremediation and multi-process hybrid technologies. Additionally, the scope of the effectiveness and limitations of individual technologies in treating the petroleum hydrocarbon polluted sites are also evaluated.

Exploring the bioremediation capability of petroleum-contaminated soils for enhanced environmental sustainability and minimization of ecotoxicological concerns

The bioremediation of soils contaminated with petroleum hydrocarbons (PHCs) has emerged as a promising approach, with its effectiveness contingent upon various types of PHCs, i.e., crude oil, diesel, gasoline, and other petroleum products. Strategies like genetically modified microorganisms, nanotechnology, and bioaugmentation hold potential for enhancing remediation of polycyclic aromatic hydrocarbon (PAH) contamination. The effectiveness of bioremediation relies on factors such as metabolite toxicity, microbial competition, and environmental conditions. Aerobic degradation involves enzymatic oxidative reactions, while bacterial anaerobic degradation employs reductive reactions with alternative electron acceptors. Algae employ monooxygenase and dioxygenase enzymes, breaking down PAHs through biodegradation and bioaccumulation, yielding hydroxylated and dihydroxylated intermediates. Fungi contribute via mycoremediation, using co-metabolism and monooxygenase enzymes to produce CO2 and oxidized products. Ligninolytic fungi transform PAHs into water-soluble compounds, while non-ligninolytic fungi oxidize PAHs into arene oxides and phenols. Certain fungi produce biosurfactants enhancing degradation of less soluble, high molecular-weight PAHs. Successful bioremediation offers sustainable solutions to mitigate petroleum spills and environmental impacts. Monitoring and assessing strategy effectiveness are vital for optimizing biodegradation in petroleum-contaminated soils. This review presents insights and challenges in bioremediation, focusing on arable land safety and ecotoxicological concerns.

Bioengineering for the Microbial Degradation of Petroleum Hydrocarbon Contaminants

Petroleum hydrocarbons are relatively recalcitrant compounds, and as contaminants, they are one of the most serious environmental problems. n-Alkanes are important constituents of petroleum hydrocarbons. Advances in synthetic biology and metabolic engineering strategies have made n-alkane biodegradation more designable and maneuverable for solving environmental pollution problems. In the microbial degradation of n-alkanes, more and more degradation pathways, related genes, microbes, and alkane hydroxylases have been discovered, which provide a theoretical basis for the further construction of degrading strains and microbial communities. In this review, the current advances in the microbial degradation of n-alkanes under aerobic condition are summarized in four aspects, including the biodegradation pathways and related genes, alkane hydroxylases, engineered microbial chassis, and microbial community. Especially, the microbial communities of “Alkane-degrader and Alkane-degrader” and “Alkane-degrader and Helper” provide new ideas for the degradation of petroleum hydrocarbons. Surfactant producers and nitrogen providers as a “Helper” are discussed in depth. This review will be helpful to further achieve bioremediation of oil-polluted environments rapidly.

A review of the role of biosurfactants in the biodegradation of hydrophobic organopollutants: production, mode of action, biosynthesis and applications

The increasing influence of human activity and industrialization has adversely impacted the environment via pollution with organic contaminants, which are minimally soluble in water. These hydrophobic organopollutants may be present in sediment, water or biota and have created concern due to their toxic effects in mammals. The ability of microorganisms to degrade pollutants makes their use the most effective, inexpensive and ecofriendly method for environmental remediation. Microorganisms have the ability to produce natural surfactants (biosurfactants) that increase the bioavailability of hydrophobic organopollutants, which enables their use as carbon and energy sources. Due to microbial diversity in production, and the biodegradability, nontoxicity, stability and specific activity of the surfactants, the use of microbial surfactants has the potential to overcome problems associated with contamination by hydrophobic organopollutants.This review provides an overview of the current state of knowledge regarding microbial surfactant production, mode of action in the biodegradation of hydrophobic organopollutants and biosynthetic pathways as well as their applications using emergent strategy tools to remove organopollutants from the environment. It is also specified for the first time that biosurfactants are produced either as growth-associated products or secondary metabolites, and are produced in different amounts by a wide range of microorganisms.

Physiological and biochemical characterization and genome analysis of Rhodococcus qingshengii strain 7B capable of crude oil degradation and plant stimulation

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Strain 7B grows in the presence of up to 10% sodium chloride and degrades crude oil, oil sludge and individual hydrocarbons.

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Over 15 days of the experiment, the strain utilized 51% of oil at 28°C and 24% at 45°C.

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When colonizing the wheat root, the strain forms biofilms in the calyptrogen sheath and at the base of the root hairs.

Rhodococci are typical soil inhabitants which take part in remediation of soil polluted with hydrocarbons. In this paper, we describe a new strain, Rhodococcus qingshengii 7B, which is capable of growth and hydrocarbon degradation at 45°C and in the presence of up to 10% NaCl in the medium. The genome of the 7B strain consists of a 6,278,280 bp chromosome and two plasmids. The circular plasmid is 103,992 bp in length. The linear plasmid is 416,450 bp in length. Genome analysis revealed the genes of degradation of various hydrocarbons, resistance to salt stress and plant growth promoting activity. This strain is promising for use in remediation of oil-contaminated soils, because it has a pronounced ability to utilize crude oil, oil sludge and individual hydrocarbons in a wide temperature range. Over 15 days of the experiment, the strain utilized 51% of crude oil at 28°C and 24% at 45 °С.