Optimization of medium using response surface methodology for l-DOPA production by Pseudomonas sp. SSA

• Optimization of nutritional parameters for bacterial l-DOPA production using Response surface methodology.
• The Plackett–Burman design and Box–Behnken design was employed for optimization of media.
• The maximum l-DOPA production obtained experimentally was found to be 3.251 ± 0.12 g l−1.

l-3,4-Dihydroxyphenylalanine (l-DOPA) is the most potent drug used for treatment of Parkinsonism. Statistical optimization of nutritional parameters for the production of l-DOPA by Pseudomonas sp. SSA has been carried out using response surface methodology (RSM). Four most significant medium constituents identified by initial screening method of Plackett–Burman (PB) were glucose, peptone, l-tyrosine and CuSO4. In order to investigate quantitative effects of the four variables selected from PB design on l-DOPA production, Box–Behnken design was subsequently employed for further optimization. The medium having glucose 1.69 g l−1, peptone 1.61 g l−1, l-tyrosine 4.11 g l−1 and CuSO4 0.03 g l−1 was found to be optimum for maximum l-DOPA production. The optimization strategies used lead to a 6.27-fold increase in l-DOPA yield (3.251 ± 0.12 g l−1) compared to non-optimized medium (0.572 ± 0.1 g l−1). l-DOPA produced was further characterized by spectroscopic techniques, such as HPTLC, HPLC and GC–MS.