Enhanced biodegradation of caffeine by Pseudomonas sp. using response surface methodology

Abstract

Pseudomonas sp. NCIM 5235 capable of degrading high concentrations of caffeine (>5 g/l) has been previously isolated from the soil of coffee plantation area. The critical medium components viz., KH 2PO 4, Na 2HPO 4, caffeine and Fe 2+ affecting the rate of caffeine degradation were determined by Plackett–Burman design. These critical parameters were further optimized using response surface methodology. The optimum concentrations of KH 2PO 4, Na 2HPO 4, caffeine and Fe 2+ were found to be 3.4 g/l, 0.352 g/l, 6.4 g/l and 0.075% (w/v), respectively. Under optimal conditions the caffeine degradation rate was increased to 0.18 g/(l h) from 0.1 g/(l h). Although the approach used for optimization is conventional, the increase in the rate of degradation of caffeine is significant. This is the first report on a strain capable of growing at higher concentrations of caffeine (>5 g/l) at maximum rate of degradation (0.18 g/(l h)).