Biodegradation of naphthalene using Kocuria rosea isolated from a Sawmill in Ikenne, Southwestern Nigeria

Naphthalene, a common member of the polycyclic aromatic hydrocarbons (PAHs) found in various industrial applications, has garnered attention due to its genotoxic, mutagenic, and potentially carcinogenic effects on living organisms. Concerns have escalated regarding the widespread presence of naphthalene in the environment, its resistance to biodegradation, capacity for bioaccumulation, and associated adverse impacts. In response, numerous pilot treatment approaches have been explored to mitigate the economic consequences and prevent the degradation of soil and water quality resulting from naphthalene pollution. This study investigates the degradation of naphthalene using Kocuria rosea, a microorganism previously isolated from sawdust samples collected from a Sawmill in Ikenne, Ogun State, Southwestern Nigeria. Kocuria rosea was cultivated in nutrient broth (NB) for 24 h, and its growth was quantified through UV–Visible spectrophotometric analysis. The phytotoxicity of both untreated and treated naphthalene solutions was assessed by measuring their impact on the germination of Zea mays (corn) seeds. Furthermore, biodegradation of naphthalene was confirmed by analyzing FT-IR spectra. The results indicate that naphthalene exhibits phytotoxic effects on Z. mays germination, whereas treatment with the Kocuria rosea solution substantially increased the germination rate from 13.3 % to 46.67 %. FT-IR analysis reveals that Kocuria rosea effectively degrades naphthalene, as evidenced by the disappearance of characteristic peaks at 3049.56, 1593.25, 958.65, and 781.2. In conclusion, Kocuria rosea, isolated from a Sawmill in Ikenne, demonstrates significant potential for the bioremediation of naphthalene, offering promise as an environmentally friendly and cost-effective approach for mitigating naphthalene pollution.