Uncovering Competitive and Restorative Effects of Macro- and Micronutrients on Sodium Benzoate Biodegradation

A model aromatic compound, sodium benzoate, is generally used for simulating aromatic pollutants present in textile effluents. Bioremediation of sodium benzoate was studied using the most abundant bacteria, Pseudomonas citronellolis, isolated from the effluent treatment plants of South Gujarat, India. Multiple nutrients constituting the effluent in actual conditions are proposed to have interactive effects on biodegradation which needs to be analyzed strategically for successful field application of developed bioremediation process. Two explicitly different sets of fractional factorial designs were used to investigate the interactive influence of alternative carbon, nitrogen sources, and inorganic micronutrients on sodium benzoate degradation. The process was negatively influenced by the co-existence of other carbon sources and higher concentration of KH₂PO₄ whereas NH₄Cl and MgSO₄ exhibited positive effects. Optimized concentrations of NH₄Cl, MgSO₄, and KH₂PO₄ were found to be 0.35, 1.056, and 0.3 mg L^-1 respectively by central composite designing. The negative effect of high amount of KH₂PO₄ could be ameliorated by increasing the amount of NH₄Cl in the biodegradation milieu indicating the possibility of restoration of the degradation capability for sodium benzoate degradation in the presence of higher phosphate concentration.