GC-MS hydrocarbon degradation profile data of Pseudomonas frederiksbergensis SI8, a bacterium capable of degrading aromatics at low temperatures

Chemical Method for Recovery and Regeneration of Graphene Oxide

Graphene oxide (GO) has been developed as a very effective medium for filtration and removal of microbial contaminants in fuel. GO is capable of filtering out microorganisms without needing micrometer and submicrometer pores for filtration. Our previous studies showed that microorganisms are attracted by GO and bind irreversibly to GO without promoting bacterial growth. Therefore, GO was tested as a filter medium to remove microorganisms in fuel. The characterization results showed that GO removed microbes in diesel fuel with >99% efficiency. However, the synthesis of GO using Hummers' method is labor intensive and a time-consuming. We present in this paper an economical, less labor intensive and a simple chemical approach to recover GO after it has been used as a filtration medium for the removal of microorganisms in fuels. In the GO recovery process, microbial and fuel contaminated GO is washed with hexane to remove any fuel from the GO sample. The hexane-washed GO is further washed with acetone and mixed with ethanol to kill and remove any microorganisms. After washing with ethanol, the GO sample is sonicated in water to remove impurities and re-establish the oxygen functionalities. The final recovered-GO (rec-GO) is obtained after removing water by rotary evaporation. The chemical characterization of rec-GO showed that rec-GO is similar in both chemical and physical properties compared to freshly synthesized-GO (as-syn-GO). Rec-GO was shown to perform similarly to as-syn-GO in filtration of biocontaminated fuel. We estimate that our rec-GO is at least 90% cheaper than high quality commercially available GO.

Pseudomonas in environmental bioremediation of hydrocarbons and phenolic compounds- key catabolic degradation enzymes and new analytical platforms for comprehensive investigation

Pollution of the environment with petroleum hydrocarbons and phenolic compounds is one of the biggest problems in the age of industrialization and high technology. Species of the genus Pseudomonas, present in almost all hydrocarbon-contaminated areas, play a particular role in biodegradation of these xenobiotics, as the genus has the potential to decompose various hydrocarbons and phenolic compounds, using them as its only source of carbon. Plasticity of carbon metabolism is one of the adaptive strategies used by Pseudomonas to survive exposure to toxic organic compounds, so a good knowledge of its mechanisms of degradation enables the development of new strategies for the treatment of pollutants in the environment. The capacity of microorganisms to metabolize aromatic compounds has contributed to the evolutionally conserved oxygenases. Regardless of the differences in structure and complexity between mono- and polycyclic aromatic hydrocarbons, all these compounds are thermodynamically stable and chemically inert, so for their decomposition, ring activation by oxygenases is crucial. Genus Pseudomonas uses several upper and lower metabolic pathways to transform and degrade hydrocarbons, phenolic compounds, and petroleum hydrocarbons. Data obtained from newly developed omics analytical platforms have enormous potential not only to facilitate our understanding of processes at the molecular level but also enable us to instigate and monitor complex biodegradations by Pseudomonas. Biotechnological application of aromatic metabolic pathways in Pseudomonas to bioremediation of environments polluted with crude oil, biovalorization of lignin for production of bioplastics, biofuel, and bio-based chemicals, as well as Pseudomonas-assisted phytoremediation are also considered.

Short-Term Effect of Green Waste and Sludge Amendment on Soil Microbial Diversity and Volatile Organic Compound Emissions

Soil amendments with organic waste products (OWPs) have been widely supported in Europe to improve soil fertility, causing wide changes in the microbial community structure and diversity, especially in the short-term period. Those changes are known to affect the volatile organic compound (VOC) emissions by soil. This work aimed to characterize, in terms of quantity and composition, the effect of green waste and sludge (GWS) application on soil VOC emissions and microbial community 49 h after the last GWS application. Two different soil samples were compared to test the effect of the soil history on VOC emissions and microbial communities. For this reason, we chose a soil that received GWS input for 20 years (GWS sample) and one that did not receive any organic input during the same period (CN sample). Furthermore, samples were manipulated to generate three microbial dilution diversity gradients (low, medium, and high). Results showed that Bacteroidetes phyla took advantage of the GWS application in all samples, increasing their relative abundance by 22% after 49 h, while the Proteobacteria phylum was penalized by the GWS amendment, passing from 58% to 49% relative abundance 49 h after the GWS application. Microbial structure differences between microbial diversity dilution levels remained even after the GWS application. GWS amendment induced a change in the emitted VOC profiles, especially in samples used to receiving GWS. GWS amendment doubled the VOC emissions from samples used to receiving GWS after 49 h. Finally, the microbial community was strongly correlated to the VOC emissions. Firmicutes, Proteobacteria, Actinobacteria, and Crenarchaeota were positively correlated (Pearson coefficient > 0.6), while other phyla, such as Bacteroidetes and Verrucomicrobia, were found to be negatively correlated (Pearson coefficient < −0.6) to the VOC emissions. After the addition of GWS, these correlations shifted from positive to negative and from negative to positive.