Bioremediation has become a trending and developing field in environmental restoration through the use of micro-organisms to utilize and reduced the concentration and toxicity of various chemical pollutants. This study is on bioremediation of hydrocarbon-polluted soils using some agricultural wastes. Ninety (90) plastic buckets were filled with 4kg each of the composite soil. The soil contained in the plastic buckets was spiked with 250ml crude oil, except in the unpolluted plastic buckets (0%) crude oil. The agro-wastes (plantain stem sap, bush mango peels, and fruited pumpkin husk powder) in single and combined forms were applied after 14 days soil pollution. The amendments were applied as follows: Pristine control (0% agro-wastes), crude-oil control (0% agro-wastes), 150g, 250g, and 350g of the agro-wastes. Soil samples were collected at 90 days for soil microbial counts and the total hydrocarbon content of the soil. Data collected were subjected to 2-way ANOVA. The result showed that the microbial population in the crude-oil polluted soil amended with different agricultural wastes significantly increased (p<0.05) the total heterotrophic and crude oil utilizing bacterial and fungal counts in the soils and the increase in microbial population result in a significant reduction in total hydrocarbon content (THC) of the soils. The reduction in the THC of the soil was treatment dependent. It is, therefore concluded that based on the efficiency of these agro-wastes in enhancing microbial degradation, further studies should be carried out on the enzyme activities and production of bio-surfactant from the wastes to shorten the degradation time.

Plastics are the most rapidly growing materials in terms of production and consumption. The durability, inertness, light weight, flexibility, and low cost are the key characteristics that make plastic suitable for application in various fields, including the construction, automotive, electronics, and packaging industries. Due to widespread usage in daily life and many industrial processes and operations, more than 300 million tons of plastic waste are produced globally annually. Indiscriminate use of plastics such as polyethylene causes environmental pollution and impacts human health due to irreversible changes in the ecological cycle. Due to its low biodegradability, polyethylene accumulation has recently emerged as a momentous environmental concern. The conventional methods, such as recycling or disposing of polyethylene, are exorbitant, and incineration results in the emission of toxic chemical compounds. Therefore, the most recent research progressively focused on the biodegradation of polyethylene with the application of bacteria as novel approaches to counteract plastic waste. This review summarizes the type of polyethylene and the environmental issues. It also briefly discussed the genes and enzymes of bacteria involved in the degradation of polyethylene. In addition, it attempts to address factors influencing degradation and techniques used for monitoring degradation.