Production of melanin by soil microbial isolate on fruit waste extract: two step optimization of key parameters

In this study, optimization of production parameters influencing melanin production in an economical fruit waste extract was attempted using a garden soil isolate (Bacillus safensis). Taguchi approach was adopted for screening of critical parameters and further optimization was done using a central composite design of response surface methodology (RSM). At optimum conditions (pH 6.84 and Temp 30.7 °C), a significant yield of ∼6.96 mg/mL was observed. Statistical analysis revealed that the experimental results fitted well to the statistical model with model R² value 0.982. The optimization of process parameters using RSM reported a 15% increase in the pigment yield than average yield obtained from the studied model. The melanin produced was confirmed by UV-visible spectroscopy, FTIR and XRD analysis. Moreover melanin obtained has significant photoprotective, radical scavenging and metal chelating activity. Thus, B. safensis has the potential to be a new source for the production of melanin, which is of industrial interest.