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Atrazine herbicide is known to disrupt the endocrine system and is potentially carcinogenic. Its continual application leads to high residue levels in soil, causing water pollution, which when consumed is associated with devastating health effects. This research reported the isolation and characterization of a new bacterial strains from active agricultural soil with the potential to biodegrade atrazine as a sole carbon source. An enrichment method was utilized to isolate the bacteria (A1, A2, B1, B2, C1 and C2) on mineral salt media (MSM) following serial dilution. Six isolates were screened for their tolerance to various concentrations of atrazine (500 to 1500 mg∙L‐1), and only isolate B1 tolerated up to 1500 mg∙L‐1 atrazine. The isolate was identified molecularly as Bacillus safensis strain BUK_BCH_BTE6 based on 16S rRNA gene sequencing and molecular phylogenetic analysis. Characterization of the isolate based on the effects of temperature, pH, substrate concentration, incubation time, inoculum size, and heavy metals revealed optimum growth and atrazine degradation at 35 °C, a pH of 7.5, 400 mg∙L‐1, at 48 h, and inoculum size of 600 µL, respectively. The growth of the isolate was inhibited by 2 ppm Hg, Cd, Cr, Pb, Ar, and Ni, while Fe, Cu, and Zn stimulated it. GC‐MS analysis revealed a degradation efficiency of 88.85% within 120 h, while metabolites such as desethyldeisopropylatrazine, deisopropylatrazine, N‐ethylammelide, and cyanuric acid were also detected. This isolate is a highly atrazine‐tolerant and efficient atrazine degrader that could be employed for bioremediation of atrazine‐polluted sites.

Lead is one of the most toxic heavy metals ever known by man today, which has zero biological role. It is known to cause anemia and affect the nervous and reproductive systems with irreversible effects. Its continual usage leads to its high accumulation polluting the soil and water bodies with devastating health effects. This research, aimed at isolation and characterization of indigenous lead tolerant bacteria from contaminated soil of Anka. Results of Atomic Absorption Spectrophotometry (AAS) showed high concentration of lead (738 mg/kg) of the affected sites above the EPA standard (400 mg/kg). Similarly, a mineral salt media was used to isolate the bacteria following serial dilution. An indigenous bacterial isolate (Ac) with potential to tolerate up to 3000 mg/L Pb(NO3)2 was isolated and molecularly identified based on 16s rRNA sequencing as Bacillus cereus strain BUK_BCH_BTE2 with the accession number MT160412. The isolate was further characterized for its optimum growth and tolerance conditions using one factor at a time (OFAT). Sucrose with an optimum concentration of 5 g/L was the best carbon source for the isolate. The isolate was found to utilize ammonium sulphate as the best nitrogen source at a concentration of 2.5 g/L, with an optimum pH and tempertaure of 7.0 and 37 °C respectively. A concentration of 1000 mg/L Pb(NO3)2 was found to be the optimum concentration for the isolate. The optimum incubation time and inoculum size were found to be 48 hrs and 100 μL respectively. The fact that the isolate could tolerate high Pb(NO3)2 concentration makes it suitable for future bioremediation work involving lead.

Bioremediation process is one of the most effective methods which facilitates the cleaning of contaminated sites and restores contaminated sites through the broad biodegradative capabilities evolved by microorganisms towards undesirable organic compounds. In this study, Alcaligenes sp. with potential to degrade and utilize used engine oil as its source of carbon and energy was isolated, identified and its growth parameters optimized for efficient and better breakdown of the pollutant. Alcaligenes sp. was isolated from a used engine oil contaminated soil in an old mechanic shop, after enrichment using a carbon free (Bush-Nell Haas) media which was supplemented with used engine oil. The bacterium was identified (morphologically, biochemically, and molecularly) and studied for its ability to extract carbon from used engine oil hence degrading used engine oil. Thereafter, the various growth parameters of the bacterium isolate were optimized. Data obtained showed optimum growth parameter of 2% (v/v) used engine oil (carbon source), pH 7, temperature 37 °C, inoculum size 2 ml and incubation time 240 hours. Also, measured ribosomal RNA (16S RNA) sequence and phylogenetic analysis revealed that the isolate is a very close relative of Alcaligenes species. The degradation potential of the isolate was assessed using gravimetric analysis, and a percentage degradation of 92.5% was discovered. Overall, the results of this study suggest that Alcaligenes sp. can effectively degrade used engine oil, hence, a potential remediation organism against engine oil contamination and spills on soils or water surface.

Chromium, a transition metal element widely distributed in the earth's crust, with the valence from −2 to +6, but exists mainly in the form of trivalent and hexavalent states. Hexavalent chromium Chromium (VI) is often found in soil and ground water due to its widespread industrial use such as tannery, electroplating, and steel industries. Chromium (VI) is toxic, mutagenic, carcinogenic, and teratogenic and much more toxic to many plants, animals, and bacteria inhabiting aquatic environments because it is motile, highly toxic, soluble in water and it is a strong oxidizing agent that causes severe damage to cell membranes while the trivalent chromium Cr (III) is the most stable form of chromium and relatively immobile in the aquatic system due to its lower solubility. This study therefore, aims at identifying a bacterium that can reduce Chromium (IV) to (III) using a pour plate technique on Luria Bertani medium amended with K2Cr2O7. Graphs and tables were used for the data analysis. The effects of incubation time, pH, temperature, inoculum size, and potassium dichromate (K2Cr2O7) concentration were then examined to characterize the bacterium based on one factor at a time. To assess Chromium (VI) reduction, a spectrophotometric study of the 1, 5-diphenyl carbazide test (DPC) at 370 nm was utilized. By using molecular phylogenetic analysis and partial 16s ribosomal RNA analysis, the isolate was found to be Acinetobacter sp. strain BUK_BCH_BTE 5. The findings demonstrated that tryptic soy broth (TSB), with an optimal K2Cr2O7 level of 200 mg/L, pH of 6.5, 35 °C temperature, inoculum size of 2%, as well as incubation time of 48 h, was the most successful approach for decreasing chromium (VI). Following Nickel (Ni), the isolate was found to withstand the highest doses of Lead (Pb), Mercury (Hg), Zink (Zn), Iron (Fe), Cadmium (Cd), Arsenic (As), and Cupper, in that order. A reduced culture's (supernatant) larvacidal bioassay showed a 30% decrease in toxicity in just 48 hours, indicating that the isolate is a promising candidate, and that the reduction method is less dangerous for decontaminating chromium-contaminated environments.

Textile industry wastewater contains azo dye leftovers, which have a deleterious impact on most environmental systems. Because of safety and cost considerations, biological waste treatment is the best alternative. The goal of the study was to isolate and characterized fungus that could decolorize and use azo dye (Congo red) as a single carbon source. After serial dilution on mineral salt media, the fungus was isolated using the pour plating procedure. Based on gene sequencing of ITS1 and ITS2 ribosomal RNA region and molecular phylogenetic analysis the strain was identified as Aspergillus quadrilineatus with the accession number OK178927. Temperature, pH, substrate concentration, incubation period, inoculum size, and the influence of interacting heavy metals in Mineral Salt Medium were all investigated during the characterization process Congo red is used as the sole carbon source. This fungal isolate grew and decolorized Congo red best at 400 μɡ/ml substrate concentration, 30 °C temperature, 5.0 pH, an inoculum size of 200 μL, and a 72-h incubation time. The isolate was shown to withstand up to 6 ppm of Zink (Zn), Chromium (Cr), and Cupper (Cu), with Iron (Fe) and Arsenic (Ar) showing the most inhibition. Comparing Congo red's metabolites to a standard database of organic substances. LC/MS analyses of the intermediate compounds produced during Congo red decolorization revealed the formation of Isamine blue, p-bromo-N-(2-naphthyl)-benzenesulfonamide, 4-acetomido-N,N-dicyclohexyl-3-nitrobenzene, and azobenzene-2-sulfenyl bromide as metabolites in the fungal biodegradation of Congo red. The isolate might be a good candidate for bioremediation.

In recent years, the degradation of pollutants by microorganisms has emerged as a feasible and cost-effective strategy for restoring the quality of the environment. Anthracene is an integral part of many carcinogenic polyaromatic hydrocarbons (PAHs) and causes skin irritation. The aimed of the study is to investigate the anthracene-degrading ability bacteria and from environmental samples and characterized them using an enrichment technique. The bacterial strain was identified as Achromobacter xylosoxidans based on molecular identification achieved via 16SrRNA sequencing and phylogenetic analysis. The strain, designated as BUK_BTEG6 (accession number OM52853), was found to efficiently degrade anthracene as the sole carbon and energy source. A one factor at a time (OFAT) approach was utilized to determine the optimal growth factors that include substrate concentration, temperature, pH, and inoculum size. Results indicated that 400-600 mg/L was found as the optimal growth conditions as substrate concentration with temperature to be 35 °C, pH of 7.5 after 72 hours of incubation. Moreover, the GC-MS analysis of the culture medium confirmed the presence of degradation metabolites such as 9-10 anthraquinone, anthracene cis 1,2 dihydro diol, catechol, and cis-cis muconic acid. This isolate represents a potential candidate for use in environmental bioremediation strategies aimed at eliminating anthracene contamination from the environment.