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Radionuclides produced during nuclear fission or explosion in civil industries and research activities, such as isotopes of chromium, cesium, plutonium, radium, strontium, tritium, and uranium, could be released, contaminating the natural ecosystems, which can have serious impacts on living beings, causing carcinogenesis and mutagenesis, as well as on the environment. Therefore, proper management of radionuclide and heavy metal waste from potential sources is necessary through eco-friendly remediation methods. However, it is often very tedious to degrade radionuclides and heavy metals from contaminated sites; however, these can be effectively converted into less toxic forms, minimizing their hazardous effects. Radionuclide-contaminated environments are inhabited by various microorganisms resistant to such elements. The interaction of radionuclides and microbes represents a bioremediation strategy that includes biosorption, bioleaching, biomineralization, and biotransformation to withstand such stress conditions. This chapter provides a review of the sources of radionuclides and their effects on the environment, and it elucidates the microbial interaction with radionuclides. In addition, the advancement of biotechnological applications in bioremediation and approaches for environmental pollution control through detoxification and degradation of radionuclides are discussed.

Biodegradation experiment was carried out to evaluate the effects supplementation of microbial consortium and bulking agents in biodegradation of crude oil in soil. The soil with indigenous microbes was spiked with crude oil at 50,000 ppm and a cocktail of microbial consortium at ratio 1:1:1:1 (v/w) which consist of Pseudomonas sp. UKMP 14-T, Acinetobactersp. UKMP 12-T and two fungi isolates Trichodermasp. (TriUKMP-1M and TriUKMP-2M). Bulking agents (sugarcane baggasse (SB) and empty fruit bunch (EFB) from oil palm) at 15% and 20% (w/w), respectively were added and mixed thoroughly. The pH and moisture content of the soil was maintained at 6.5 and 40% VWC, respectively. The degradation of crude oil from the soil was analyzed using gas chromatography-flame ionization detector (GC-FID) and the growth of bacteria was estimated using spread plate method. The result showed that biodegradation of crude oil by microbial consortium with addition of SB produced 100% Total Petroleum Hydrocarbon (TPH) degradation as compared to 91% with EFB after 30 days incubation. The control plot which contains only indigenous microbes showed 62% degradation at the same period of incubation. The results indicate that the types of the bulking agent may influence the intake of the nutrient source by microbial consortia hence influenced the percentage of the TPH degradation.

Hydrocarbon waste, including crude oil residues in tank bottoms represents an ongoing and growing environmental problem throughout the world as they are particularly persistent within the environment and have the potential to induce a vast array of serious negative health effects for all biological entities. Bioremediation offers a sustainable treatment that reduces the levels of a pollutant present in a soil, for example to sub-toxic concentrations or brings them in line with compliance criteria for safe use or for disposal. In so doing, the risk following release to the environment is ameliorated. The aim of this study was to assess the potential of a hydrocarbonoclastic bacterial consortium, isolated from previously contaminated environments to both survive in contaminated environments and degrade weathered crude oil. Significant changes in the waste oil occurred through incubation with the microbial consortia including, emulsification, loss of viscosity and reduced hydrocarbon content, particularly in the high carbon chain (C20-C70 region). Profiling of the microbial community using denaturing gradient gel electrophoresis confirmed the influence of the addition of the microbial consortia on enhanced diversity of the microflora. Sequence identity of the individual strains present in the microbial consortia identified Pseudomonas sp. as well as several non-cultured gamma-proteobacteria. The result highlights the potential of hydrocarbonoclastic bacterial consortia for use in bioremediation.