ABSTRACT
BACKGROUND: Discharged effluents from industry have been responsible for the deterioration of the aquatic environment in many parts of the world, especially in developing countries. Increasing industrialization and urbanization have resulted in the discharge of large amounts of waste into the environment, resulting in high pollution loads. Utilization of microbes such as fungi and bacteria have been used for pollution degradation. OBJECTIVES: The aim of this research was to utilize microbial agents such as fungi and bacteria to reduce pollutant loads such as heavy metals in effluent samples. METHODS: Three types of effluent (pharmaceutical, textile effluent, and dye) were obtained from Surulere in Lagos Metropolitan Area, Nigeria. Heavy metals analysis was carried out using a flame atomic adsorption spectrophotometer according to standard methods. Samples were cultured for microbes and identified. Bacteria samples were inoculated on nutrient agar and incubated at 37°C for 24 hours. Fungi counts were carried out using potato dextrose agar and incubated at 28°C for 3-5 days. The isolated organisms were identified based on their morphological and biochemical characteristics. Then 100 mL of the effluents was dispensed into 250 mL flasks, and the pH of the medium was adjusted to 7.2 by the addition of either sodium hydroxide or hydrogen chloride and autoclaved at 121°C for 15 minutes. The autoclaved flask was inoculated with 1 mL of bacteria and fungi for 21 days and pH was recorded properly every 48 hours. RESULTS: The results of the physicochemical parameters indicated that conductivity, total suspended solids, total dissolved solids, turbidity, chemical oxygen demand and biochemical oxygen demand for all the three industrial effluents were higher than the World Health Organization (WHO) permissible limits. Heavy metal analysis results show that the effluents had high values for cadmium, above the WHO limit of 0.003 mg/L. Concentrations of zinc ranged from 0.136-1.690 mg/L, and nickel ranged between 0.004-0.037mg/L for the three effluents, within the WHO limit. The identified bacteria were Bacillus subtilis, Klebsiella pneumonia, Salmonella typhi and Bacillus cereus and isolated fungi were Aspergillus flavus and Penicillium chrysogenum. All the physicochemical parameters and heavy metal concentrations were reduced after the biodegradation study in the effluents. CONCLUSIONS: The responses observed in the various microbes indicated that the use of microbes for the reduction of environmental pollutants has an advantage over the use of other methods because it is environmentally friendly, low cost, and no new chemicals are introduced into the environment. This method should be encouraged for pollution reduction to bring about ecosystem sustainability advocated for Ghana.
