Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process

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Abstract:

Pyrene and benzo[a]pyrene (BaP) are high molecular weight polycyclic aromatic hydrocarbons (PAHs) recalcitrant to microbial attack. Although studies related to the microbial degradation of PAHs have been carried out in the last decades, little is known about degradation of these environmental pollutants by fungi from marine origin. Therefore, this study aimed to select one PAHs degrader among three marine-derived basidiomycete fungi and to study its pyrene detoxification/degradation. Marasmiellus sp. CBMAI 1062 showed higher levels of pyrene and BaP degradation and was subjected to studies related to pyrene degradation optimization using experimental design, acute toxicity, organic carbon removal (TOC), and metabolite evaluation. The experimental design resulted in an efficient pyrene degradation, reducing the experiment time while the PAH concentration applied in the assays was increased. The selected fungus was able to degrade almost 100% of pyrene (0.08mgmL−1) after 48h of incubation under saline condition, without generating toxic compounds and with a TOC reduction of 17%. Intermediate metabolites of pyrene degradation were identified, suggesting that the fungus degraded the compound via the cytochrome P450 system and epoxide hydrolases. These results highlight the relevance of marine-derived fungi in the field of PAH bioremediation, adding value to the blue biotechnology.

 

Vieira, Gabriela A.L., Magrini, Mariana Juventina, Bonugli-Santos, Rafaella C., Rodrigues, Marili V.N., Sette, Lara D. (2018).  Polycyclic aromatic hydrocarbons degradation by marine-derived basidiomycetes: optimization of the degradation process. Brazilian Journal of Microbiology xxx (2018) p xxx-xxx. dx.doi.org/10.1016/j.bjm.2018.04.007.

 

In this article, the researchers investigate the potential of 3 basidiomycete fungal strains isolated from ocean sponges in Brazil to degrade high molecular weight PAHs. One of the three fungal strains showed a much higher potential to degrade pyrene and Benzo(a)pyrene (BaP), so the researchers designed a series of experiments to determine several optimum environmental conditions for the fungal strain to degrade pyrene and BaP. The researchers also tested toxicity of the degradation products using shrimp larvae, and saw a significant decrease in toxicity from a solution of only pyrene, to a solution of pyrene and the degrading fungal strain. The study provides an important look at a fungal strain with enormous potential to degrade toxic PAHs pollution in the environment.

This article interests me because fungi aren’t often the focus of microbiological research, let alone marine fungi. While the paper hasn’t yet been published in print and is so far only available online, I’m interested in seeing if this paper will influence commercial bioaugmentation products in the future.

Bioremediation of contaminants by plants

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Bioremediation of contaminants by plants

https://www.bbc.com/earth/story/20141111-plants-have-a-hidden-internet Introduction Whenever you see oil rigs or pollutants cover the soil, you must be pondering how much of a deal contaminants are to the environment. To put it into perspective, oil spills that come from industrial activities such as petroleum engineering and waste disposal is a problematic global issue for the environment. The conventional …

Sulfolane bioremediation

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Title: Factors limiting sulfolane biodegradation in contaminated subarctic aquifer substrate

Argument: Sulfolane is a manmade compound used in petroleum refining. As such, it has no natural metabolic pathway to mineralization known yet. It is also very water soluble so should it spill, it is very likely to create plumes in groundwater. Sulfolane is of interest to the Fairbanks area since we have one such plume originating at the north pole refinery. Several microbiologists are examining sulfolane plumes and growing enrichment cultures from them, hoping to find an organism that has developed a metabolic pathway capable of degrading sulfolane. This is one such paper.

Citation:

Kasanke CP, Leigh MB (2017) Factors limiting sulfolane biodegradation in contaminated subarctic aquifer substrate. PLoS ONE 12(7): e0181462. https://doi.org/10.1371/journal. pone.0181462

Abstract:

Sulfolane, a water-soluble organosulfur compound, is used industrially worldwide and is associated with one of the largest contaminated groundwater plumes in the state of Alaska. Despite being widely used, little is understood about the degradation of sulfolane in the envi- ronment, especially in cold regions. We conducted aerobic and anaerobic microcosm stud- ies to assess the biological and abiotic sulfolane degradation potential of contaminated subarctic aquifer groundwater and sediment from Interior Alaska. We also investigated the impacts of nutrient limitations and hydrocarbon co-contamination on sulfolane degradation. We found that sulfolane underwent biodegradation aerobically but not anaerobically under nitrate, sulfate, or iron-reducing conditions. No abiotic degradation activity was detectable under either oxic or anoxic conditions. Nutrient addition stimulated sulfolane biodegradation in sediment slurries at high sulfolane concentrations (100 mg L-1), but not at low sulfolane concentrations (500 μg L-1), and nutrient amendments were necessary to stimulate sulfo- lane biodegradation in incubations containing groundwater only. Hydrocarbon co-contami- nation retarded aerobic sulfolane biodegradation rates by ~30%. Our study is the first to investigate the sulfolane biodegradation potential of subarctic aquifer substrate and identi- fies several important factors limiting biodegradation rates. We concluded that oxygen is an important factor limiting natural attenuation of this sulfolane plume, and that nutrient amend- ments are unlikely to accelerate biodegradation within in the plume, although they may bios- timulate degradation in ex situ groundwater treatment applications. Future work should be directed at elucidating the identity of indigenous sulfolane-degrading microorganisms and determining their distribution and potential activity in the environment.

Acceleration of organic removal and electricity generation from dewatered oily sludge in a bioelectrochemical system by rhamnolipid addition

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Citation:

Zhang, Y., Zhao, Q., Jiang, J., Wang, K., Wei, L., Ding, J., & Yu, H. (2017). Acceleration of organic removal and electricity generation from dewatered oily sludge in a bioelectrochemical system by rhamnolipid addition.  Bioresource technology,  243, 820-827.

Abstract:

Conversion of biomass energy of dewatered oily sludge to electricity is the rate-limiting process in bioelectrochemical system (BES). In this study, 2  mg  g−1rhamnolipids were added to dewatered oily sludge, resulting in a significant enhancement in maximum power density from 3.84   ±  0.37 to 8.63   ±  0.81  W  m−3, together with an increase in total organic carbon (TOC) and total petroleum hydrocarbon (TPH) removal from 24.52   ±  4.30 to 36.15   ±  2.79  mg  g−1  and 29.51   ±  3.30 to 39.80   ±  2.47  mg  g−1, respectively. Rhamnolipids can also enhance the solubilization and promote the hydrolysis of dewatered oily sludge with increases in SOCD from 14.93   ±  2.44 to 18.40   ±  0.08  mg  g−1  and VFAs from 1.02   ±  0.07 to 1.39   ±  0.12  mg  g−1. Furthermore, bacteria related to substrate degradation were predominant in dewatered oily sludge, and bacteria related to the sulfate/sulfide cycle were significantly enriched by rhamnolipid addition.

Justification:

I initially found this paper interesting because the overall process being looked at uses bioremediation of petroleum waste as a mechanism for generating electricity. This covers how the addition of Rhamnolipids improves the process’s effectiveness and how the active bacterial composition changes after its addition.

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Enhancing pesticide degradation using indigenous microorganisms

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Citation

Diaz, J. et al. Enhancing pesticide degradation using indigenous microorganisms isolated under high pesticide load in bioremediation systems with vermicomposts. 2016. Bioresource Technology. 214: 234-241.

 

Abstract

In biobed bioremediation systems (BBSs) with vermicomposts exposed to a high load of pesticides, 6 bacteria and 4 fungus strains were isolated, identified, and investigated to enhance the removal of pesticides. Three different mixtures of BBSs composed of vermicomposts made from greenhouse (GM), olive-mill (OM) and winery (WM) wastes were contaminated, inoculated, and incubated for one month (GMI, OMI and WMI). The inoculums maintenance was evaluated by DGGE and Q-PCR. Pesticides were monitored by HPLC-DAD. The highest bacterial and fungal abundance was observed in WMI and OMI respectively. In WMI, the consortia improved the removal of tebuconazole, metalaxyl, and oxyfluorfen by 1.6-, 3.8-, and 7.7-fold, respectively. The dissipation of oxyfluorfen was also accelerated in OMI, with less than 30% remaining after 30 d. One metabolite for metalaxyl and 4 for oxyfluorfen were identified by GC—MS. The isolates could be suitable to improve the efficiency of bioremediation systems.

 

Link

https://www.sciencedirect.com/science/article/pii/S0960852416306010

 

This paper shows some practical applications of microbes as bioremediators, exploring the processes of bioremediation in contaminated vericomposts. It explores ways of bioremediation of agricultural waster with microbes.

 

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Predictable bacterial composition and hydrocarbon degradation in Arctic soils following diesel and nutrient disturbance

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Citation:

Terrence H. Bell, Yergeau, E., Maynard, C., Juck, D., Whyte, L. G., & Greer, C. W. (2013). Predictable bacterial composition and hydrocarbon degradation in Arctic soils following diesel and nutrient disturbance.  The ISME Journal 7, 1200-1210.

Abstract:

Increased exploration and exploitation of resources in the Arctic is leading to a higher risk of petroleum contamination. A number of Arctic microorganisms can use petroleum for growth-supporting carbon and energy, but traditional approaches for stimulating these microorganisms (for example, nutrient addition) have varied in effectiveness between sites. Consistent environmental controls on microbial community response to disturbance from petroleum contaminants and nutrient amendments across Arctic soils have not been identified, nor is it known whether specific taxa are universally associated with efficient bioremediation. In this study, we contaminated 18 Arctic soils with diesel and treated subsamples of each with monoammonium phosphate (MAP), which has successfully stimulated degradation in some contaminated Arctic soils. Bacterial community composition of uncontaminated, diesel-contaminated and diesel+MAP soils was assessed through multiplexed 16S (ribosomal RNA) rRNA gene sequencing on an Ion Torrent Personal Genome Machine, while hydrocarbon degradation was measured by gas chromatography analysis. Diversity of 16S rRNA gene sequences was reduced by diesel, and more so by the combination of diesel and MAP. Actinobacteriadominated uncontaminated soils with <10% organic matter, while Proteobacteria dominated higher-organic matter soils, and this pattern was exaggerated following disturbance. Degradation with and without MAP was predictable by initial bacterial diversity and the abundance of specific assemblages of Betaproteobacteria, respectively. High Betaproteobacteria abundance was positively correlated with high diesel degradation in MAP-treated soils, suggesting this may be an important group to stimulate. The predictability with which bacterial communities respond to these disturbances suggests that costly and time-consuming contaminated site assessments may not be necessary in the future.

Link:

https://www.nature.com/articles/ismej20131

Justification:

I chose this article because it investigates contamination in the Arctic, which would be interesting to  learn more about. This exploration deals with petroleum contamination, and microorganisms rely heavily on petroleum for growth-supporting carbon and energy.

Plastics in the North Atlantic garbage patch: A boat-microbe for hitchhikers and plastic degraders

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Debroas, D., Mone, A. and Ter Halle, A., 2017. Plastics in the North Atlantic garbage patch: a boat-microbe for hitchhikers and plastic degraders.  Science of the Total Environment,  599, pp.1222-1232.

Abstract:

Plastic is a broad name given to different polymers with high molecular weight that impact wildlife. Their fragmentation leads to a continuum of debris sizes (meso  to microplastics) entrapped in gyres and colonized by microorganisms. In the present work, the structure of eukaryotes, bacteria and Archaea was studied by a metabarcoding approach, and statistical analysis associated with network building was used to define a core microbiome at the plastic surface. Most of the bacteria significantly associated with the plastic waste originated from non-marine ecosystems, and numerous species can be considered as hitchhikers, whereas others act as keystone species (e.g., Rhodobacterales, Rhizobiales, Streptomycetales and Cyanobacteria) in the biofilm. The chemical analysis provides evidence for a specific colonization of the polymers. Alphaproteobacteria and Gammaproteobacteria significantly dominated mesoplastics consisting of poly(ethylene terephthalate) and polystyrene. Polyethylene was also dominated by these bacterial classes and Actinobacteria. Microplastics were made of polyethylene but differed in their crystallinity, and the majorities were colonized by Betaproteobacteria. Our study indicated that the bacteria inhabiting plastics harboured distinct metabolisms from those present in the surrounding water. For instance, the metabolic pathway involved in xenobiotic degradation was overrepresented on the plastic surface.

Justification:

I chose this paper because the accumulation of plastic in the ocean is a huge problem, and we generally think of plastics as very challenging to degrade.

Degradation of Synthetic Azo Dyes of Textile Industry: a Sustainable Approach Using Microbial Enzymes

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https://ac.els-cdn.com/S1364032117314016/1-s2.0-S1364032117314016-main.pdf?_tid=a5eb2b14-7084-4bea-a3de-feeaee407262&acdnat=1521527455_bf79b1d62c6c400907b9240f7d5afd6c

SFazal, T., Mushtaq, A., Rehman, F., Khan, A. U., Rashid, N., Farooq, W., … & Xu, J. (2017). Bioremediation of textile wastewater and successive biodiesel production using microalgae.  Renewable and Sustainable Energy Reviews.

 

Microalgal biodiesel has emerged as an environment friendly alternative to the existing fossil fuels. The commercial production of this biodiesel is still challenging due to several technical and economic issues, which span from mass cultivation of microalgae to the biodiesel production. Mass cultivation is the most critical step in terms of water and nutrient requirement. Industrial wastewater such as textile wastewater (TWW) is a cheap source for water, which additionally contains necessary nutrients (phosphate, nitrates, micronutrients etc.) and organic dyes (potential carbon source) for algae cultivation. The application of microalgae for biodiesel production employing single objective strategy is not sustainable. Microalgae can be effectively employed to bioremediate TWW (dyes and nutrients removal) and to produce biodiesel from grown microalgae. This process integration (bioremediation-biodiesel production) can potentially improve biodiesel production and wastewater treatment. However, this process coupling needs to be thoroughly investigated to identify and optimize critical process factors (algal species, cultivation and harvesting methods, bioremediation mechanism etc.). This study has reviewed the status of TWW as potential source of water and nutrients, role of different algal species in the bioremediation of TWW, different cultivation systems, harvesting and biodiesel production methods. This review also suggests future research and development challenges for coupled textile wastewater treatment and microalgal biodiesel production.

 

Justification:

I thought this paper was really interesting! It talks about the biodegradation pathways involved in textile waste water and how the processes can be coupled with other biological processes. This paper discusses a rising problem in today’s world: fast fashion and the textile industry. I think it brings up important topics that address the sustainability of such a large and fast growing industry, and how microbes can potentially be utilized to mediate.

Degradation of Deepwater Horizon oil buried in a Florida beach influenced by tidal pumping

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ABSTRACT

After Deepwater Horizon oil reached the Florida coast, oil was buried in Pensacola Beach (PB) sands to ~  70  cm depth, resulting in Total Petroleum Hydrocarbon (TPH) concentrations up to ~  2  kg per meter of beach. This study followed the decomposition of the buried oil and the factors influencing its degradation. The abundance of bacteria in oiled sand increased by 2 orders of magnitude within one week after oil burial, while diversity decreased by ~  50%. Half-lives of aliphatic and aromatic hydrocarbons reached 25 and 22  days, respectively. Aerobic microbial oil decomposition, promoted by tidal pumping, and human cleaning activities effectively removed oil from the beach. After one year, concentrations of GC-amenable hydrocarbons at PB were similar to those in the uncontaminated reference beach at St. George Island/FL, and microbial populations that disappeared after the oil contamination had reestablished. Yet, oxihydrocarbons can be found at PB to the present day.

CITATION

Huettel, M., Overholt, W. A., Kostka, J. E., Hagan, C., Kaba, J., Wells, W. B., & Dudley, S. (2018). Degradation of Deepwater Horizon oil buried in a Florida beach influenced by tidal pumping. Marine Pollution Bulletin, 126, 488-500.

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Bioremediation of pesticides in surface soil treatment unit using microbial consortia

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Abstract:

The manufacturing and use of pesticides has been rising tremendously in India. The waste generated by the pesticide industry has become an environmental problem due to the present insufficient and ineffective waste treatment technology involving physico-chemical and biological treatment. The available data indicates that pesticide residues remain in surface soil, leading to toxicity in the soilwater environment. The recent advances in bioremediation technology using microbial consortium has been found effective for treatment of pesticides in soil. In the present study, a Surface Soil Treatment Unit has been designed wherein bioremediation of commonly used pesticides namely chlorpyrifos, cypermethrin, fenvalerate, and trichlopyr butoxyethyl ester at varying concentration viz. 25, 50 and 100 mg/kg have been carried out using cow-dung microbial consortia under simulated environmental conditions. The bioremediation conditions have been monitored and maintained during the study. The investigation has been extended till the parent compound was converted into intermediates and/or less harmful compounds. These then will further mineralize, from part of the microbial food chain and/or become integrated into the humic fractions. The results presented here highlight the potential of cowdung slurry consortia for bioremediation of soil contaminated with pesticides in surface soil treatment unit.

Citation:

Geetha, M., & Fulekar, M. H. (2008). Bioremediation of pesticides in surface soil treatment unit using microbial consortia. African Journal of Environmental Science and Technology, 2(2), 036-045.

https://www.ajol.info/index.php/ajest/article/viewFile/135415/124907

I chose this article because I thought it was interesting that they took cow dung and used it’s natural microbial community to degrade certain pesticides. This could be very beneficial information for agricultural businesses. It could be a very affordable way to decrease concentrations of certain pesticides.

 

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