Department of Microbiology

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Browsing Department of Microbiology by Subject "Aspergillus niger"

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    Citric Acid Production by Aspergillus niger Cultivated on Parkia biglobosa Fruit Pulp
    (Internationally Scholarly Research Notices, 2014) Aransiola, S.A
    The study was conducted to investigate the potential of Parkia biglobosa fruit pulp as substrate for citric acid production by Aspergillus niger. Reducing sugar was estimated by 3,5‐dinitrosalicylic acid and citric acid was estimated spectrophotometrically using pyridine‐acetic anhydride methods. The studies revealed that production parameters (pH, inoculum size, substrate concentration, incubation temperature, and fermentation period) had profound effect on the amount of citric acid produced. The maximum yield was obtained at the pH of 2 with citric acid of 1.15 g/L and reducing sugar content of 0.541 mMol−1, 3% vegetative inoculum size with citric acid yield of 0.53 g/L and reducing sugar content of 8.87 mMol−1, 2% of the substrate concentration with citric acid yield of 0.83 g/L and reducing sugar content of 9.36 mMol−1, incubation temperature of 55°C with citric acid yield of 0.62 g/L and reducing sugar content of 8.37 mMol−1, and fermentation period of 5 days with citric acid yield of 0.61 g/L and reducing sugar content of 3.70 mMol−1. The results of this study are encouraging and suggest that Parkia biglobosa pulp can be harnessed at low concentration for large scale citric acid production.
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    Production of laccase by Bacillus subtilis and Aspergillus niger for treatment of textile effluent
    (Sustainable Chemistry for the Environment, 2025) Aransiola, S.A.
    The improper disposal of textile effluents without effective treatment has adverse environmental, social, economic, and health impacts and as such, it is vital to find innovative technological solutions to reduce the negative consequences of textile effluents. Laccases are versatile multicopper enzymes found in plants, fungi and other microorganisms with wide applications especially in the textile and paper industry. This study examined the production of laccase from Bacillus subtilis and Aspergillus niger to remediate textile effluent. Both organisms were identified by molecular method and plate test method was used to evaluate laccase production by the two organisms. Rice bran emerged as the substrate of choice for laccase production. At optimum temperature (30°C), the highest laccase produced was 0.522 U/mL and 0.642 U/mL at 35°C for B. subtilis and A. niger respectively. The optimum pH level of 5 and 6 produced the highest laccase yield of 0.583 U/mL and 0.684 U/mL respectively. Significant improvements of laccases from B. subtilis and A. niger were observed on physicochemical analysis of TDS, pH, electrical conductivity, TSS, temperature and DO in treating textile effluent. Notably, these enzymes exhibited remarkable efficacy reduction in BOD (38 %), COD (14 %), and nitrate (23 %) levels in the effluent. The study underscores the efficacy of laccases from the microorganisms in treating textile effluent, with concentrations ranging from 10 to 30 U/mL proving effective. However, laccase produced from B. subtilis showed more remediation potential in textile effluent treatment compared to the one produced by A. niger