Papers by Keyword: Bioremediation

Abstract: Oil spills from sources such as rigs, tankers, and offshore platforms present significant environmental, economic, and social challenges. Large spills endanger human health by contaminating ecosystems. The emulsification of crude oil from the oil spill in seawater complicates remediation efforts, highlighting the need for a better understanding of factors influencing bioremediation strategies. Recently, Chlorella sp. proven to enhance the crude oil degradation by promoting the activity of indigenous microorganisms, utilizing nutrients from the oil and mitigating toxicity. This study investigates the effects of varying salinities on the growth of Chlorella sp. and its biodegradation efficiency under different crude oil concentrations. There are three experimental mixtures that were prepared: 100% seawater, 50% seawater/50% freshwater, and 100% freshwater. Each mixture received essential minerals and periodic CO₂ tablet additions to enhance growth. Optical density readings were taken every three days over a 15-day period at a controlled temperature of 30°C to assess growth rates. The results indicated that the presence of seawater significantly enhanced Chlorella sp. growth, yielding greater biomass compared to freshwater only. Additionally, Chlorella sp. effectively degraded crude oil components, with optimal degradation at lower concentrations (2%). Fourier Transform Infrared (FTIR) analysis revealed a significant reduction in hydrocarbon peaks over two weeks. However, higher crude oil concentrations (4%) negatively impacted the algae growth due to the heightened nutrient requirements necessary for Chlorella sp. to perform efficient biodegradation. This study highlights the potential of Chlorella sp.for bioremediation in oil spill scenarios.

Abstract: Investigating the intricate microbial communities within a textile wastewater treatment system is crucial for understanding their potential role in the process, and possibly for process optimization in the future. Dye-containing wastewater sludge samples were collected from a textile industry treatment plant. Employing total genomic DNA extraction, amplicon sequencing, and sequence data analysis, this research investigated the microbial community composition in three treatment tanks. Rarefaction curves confirm adequate sequencing depth, with the aeration tank displaying the highest reads. Alpha diversity reveals richer microbial communities in the anoxic tank, while all samples demonstrate similar diversity and species richness. Proteobacteria dominate at the phylum level, predominantly in the aerobic tank, signifying their involvement in nitrogen removal. Conversely, anoxic sludge features Planctomycetota and Thermotogota, potentially participating in anaerobic processes. Genus-level analysis highlights the potential significance of SM1A02 in nitrogen metabolism under anoxic conditions, while Denitratisoma dominates in aerobic tank, indicating denitrification as the main process in this tank. This study offers valuable insights into the microbial community members present in the textile wastewater treatment system, and their potential roles, towards a more sustainable biodegradation strategies of dye-containing wastewater.

Abstract: From food to environmental applications, the encapsulation of bio-objects in nanofibers is widely used. In particular, for improved and sustainable performance of bioremediation, the system requires the development of cost-effective nanomaterials that containing living microorganisms for textile wastewater treatment is required. Here, bacteria-encapsulated polyethylene oxide (PEO) nanofibers (Nfs) were prepared by electrospinning. According to the Scanning Electron Microscope (SEM) images, PEO-Nfs show bead-free morphology and homogeneous distribution, while random expansions are observed in the nanofibers after bacterial encapsulation. While the number of live bacteria in the polymer before electrospinning was 10¹⁰ CFU/mL, the number of live bacteria-encapsulated after spinning was 10⁸ CFU/mL. This proves that nanofibers carry a very high number of bacteria after electrospinning which is supported by Fluorescence microscope images. Furthermore, an ATR-FTIR study confirmed the molecular interactions between PEO and bacteria in the nanofibers. The removal efficiency of PEO_bacteria-Nfs was 26.6 ± 0.3% at 5 ppm and 9 ± 0.1% at 20 ppm dye concentration. Under storage conditions of +4 °C, the bacteria-encapsulated in PEO-Nfs show cell viability for more than 60 days. In order to extend the research on bacteria-encapsulated polymer Nfs, we explored the possibility of extending the life of bacteria in electrospun Nfs by cross-linking approaches using non-toxic calcium ions. The composite Nf mats were therefore reused for up to 4 repeated cycles.

Abstract: Ammonia is a poisonous compound that can harm fish. Fish feed and manure are the primary sources of ammonia in catfish farming ponds. High concentrations of ammonia can cause death. Therefore, it is necessary to control the presence of ammonia to minimize the potential for fish mortality. Microbial Fuel Cell (MFC) is a technology that can help with ammonia bioremediation. This study aims to analyze the effectiveness of Microbial Fuel Cell (MFC) in reducing ammonia. The research method used is an experimental research method with qualitative descriptive analysis. The research was conducted on a laboratory scale using a dual-chamber Microbial Fuel Cell (MFC) reactor connected using a salt bridge. This research was conducted with variations in the use of sticky media, including without media, with bioball, and with bioring media. The results showed that the percentage of ammonia reduction in each treatment was 94.52%, 98.09%, and 99.28%. From this research, it can be concluded that Microbial Fuel Cells (MFC) are effective in reducing ammonia.

Abstract: This work studied the potentials of indigenous Micrococcus sp., Bacillus sp., Pseudomonas sp., and Escherichia coli (E. coli) for bioremediation of lead contaminated soils collected from Amita forest in Ebonyi State of Nigeria.The organisms isolated from the soils were conditioned with the predetermined optimum factors in inoculated soil samples. The samples were tested for residual lead concentration at times 8, 16, 24, 32, 40, 48, and 56 days with Atomic Absorption Spectrophotometer.The performances of the organisms were in the decreasing order of Micrococcus sp., Bacillus sp., Pseudomonas sp., and E. coli. Micrococcus sp. and Bacillus sp. performed earlier at time 16 days as against Pseudomonas sp., and E. coli at 24 days. The maximum efficiencies were discovered at time 56 days as 76.68%, 72.24%, 70.11% and 55.47% for Micrococcus sp., Bacillus sp., Pseudomonas sp., and E. coli respectively with respective residual concentrations of 31.55 mg/kg, 37.55 mg/kg, 40.44 mg/kg and 60.24 mg/kg at the respective efficiencies.The rates of removals were in the decreasing order of -0.0524d^-1 for Pseudomonas sp., -0.0714 d^-1 for Bacillus sp., -0.0743d^-1 Micrococcus sp., and 0.113 d^-1 E. coli. The fitted models showed diffusion as the rate-limiting step for removals by Pseudomonas sp., Bacillus sp., and Micrococcus sp.; while chemisorption was the rate-limiting step for removal by E. coli. This information will be helpful to researchers and decision makers for the remediation of lead contaminated soils.

Abstract: The effect of organic nutrient on the biodegradation of hydrocarbon contaminated marine sediment in Malaysia was investigated. Biodegradation was assessed in microcosm experiments containing 10% (w/w) of crude oil amended with fertilizers in three ways, which were with inorganic nutrients (NP), organic matter in the form of plant-based (Elaeis guineensis) and fish-amendments (Scomber australasicus). It was observed that hydrocarbon degradation occurred in all treatments, with the highest biodegradation rates in S. australasicus supplemented sediment. The addition of S. australasicus managed to reduce the oil concentration to 48% while the addition of E. guineensis and inorganic NP reduced the final oil concentration to 66% and 63% respectively. All three amendments show faster degradation rate compared to the control. Isolation of the soil sample on specific nutrient agar, centrimide, revealed the presence of Pseudomonas aeruginosa that are well known for its ability to degrade hydrocarbon in crude oil.

Abstract: The biosorption of cadmium and lead by Penicillium sp. isolated from an uncontaminated soil was studied at different initial metal ions concentrations. The maximum removal yields were obtained at 5 mg/L initial metal concentration. The highest removal yields were 35.67% and 81.99% for cadmium and lead respectively in the single system. In the binary system, the removal yield increased to 90.99% and 97.48% for both metal ions at the same initial concentration. This study has also confirmed that Penicillium sp was able to grow in the presence of both metal ions at different concentrations. In addition, this study showed that Penicillium sp was more tolerant to cadmium than lead. Fungi have also shown a tolerance to high concentrations of toxic heavy metals.This study can provide useful information on the bioremoval of heavy metals such as Cd(II) and Pb(II) from wastewaters.

Abstract: During the processing of refractory gold ores, cyanide (CN^-) and residual sulphur species react to form an effluent stream containing thiocyanate (SCN^-) and residual CN^-. The release of SCN^- and CN^- containing effluent water to the environment is prohibited, necessitating effective treatment prior to discharge and/or reuse of contaminated plant water. Biologically mediated effluent remediation processes have been developed for commercial use, to remediate SCN^- containing effluents, with the aim of enabling recycling of process water and improving the quality of effluent water prior to disposal. Bioremediation processes to treat these effluents rely on a complex consortium of microorganisms to metabolise the SCN^- resulting in the production of ammonium that is in turn removed by conversion to nitrite and subsequent denitrification. Increasingly, genomic methods are being used to investigate processes in wastewater treatment to identify key microbial species and, thereby, inform the rationale design and operation of these bioremediation systems. The microbial ecology of laboratory-based SCN^- degrading bioprocesses have been investigated, using genome resolved metagenomics, to provide detailed information on the community composition and metabolic profile of abundant microbial community members. Our on-going research is focused on developing a greater understanding of the heterotrophic and autotrophic populations of microorganisms within the SCN^- degrading community as well as the role of the component members in SCN^- destruction. We are interested in the formation of microbial biofilm and the spatial distribution of key microorganisms within the resulting biofilm communities. This information is being used to inform further rational development of SCN^- degradation processes for treatment of contaminated wastewater effluents.

Abstract: Biological sulfate reduction represents an alternative and sustainable option to reduce the high sulfate load, precipitate heavy metals and neutralise the acidity associated with acid rock drainage (ARD). Sulfate-reducing enrichment cultures have been developed on simple and complex electron donors from several environmental samples and used to inoculate three reactor configurations, namely a continuous stirred tank bioreactor, up-flow anaerobic packed bed reactor and a linear flow channel reactor, with varying degrees of biomass retention provided by carbon microfibres and polyurethane foam. These matrices are included to enhance microbial attachment and colonisation, allowing for the decoupling of hydraulic retention time and biomass retention time. The bioreactor systems are operated under increasingly stringent conditions through the reduction in the hydraulic residence time. The biological sulfate reduction performance and the biomass concentration of planktonic, matrix-attached and matrix-associated communities are routinely monitored. This investigation makes use of biomass quantification of the planktonic community and, following detachment, the matrix-associated community to investigate the resultant microbial communities in these reactor systems. Evaluation of these mixed microbial communities, and their link to process performance, provides an opportunity to impact the design and operation of pilot- and industrial-scale bioprocesses.

Abstract: Bioremediation is the process of detoxification or elimination of pollutants using microorganisms with different metabolic capabilities. Biodegradation by natural populations of microorganisms is one of the primary mechanisms by which oil and other pollutants of hydrocarbon origin can be removed from the environment and it is also much cheaper than the other remediation technologies.In this study, we analyzed the samples of historical waste from the oil industry, which contained sand, organic materials, heavy fuel oil and catalysts used during the process of hydrodesulfurization (HDS) of oil. The aim was to examine the fate of cobalt and molybdenum, toxic heavy metals present in those catalysts. A consortium of microorganisms isolated from the complex pollutants from the oil industry was added to the samples. During the study, beside the transformation of cobalt and molybdenum forms, we also monitored the biodegradation process of the total petroleum hydrocarbons (TPH).