Effect of the nitrogen source on caffeine degradation by Aspergillus tamarii

Aims: To evaluate caffeine degradation and nitrogen requirements during Aspergillus tamarii growth in submerged culture. Methods and Results: Aspergillus tamarii spores produced on a coffee infusion agar medium added with sucrose were used. Several caffeine and ammonium sulphate concentrations (0-1 and 0-1.36 g l(-1), respectively) were tested simultaneously on fungal biomass production and caffeine degradation. An additional caffeine pulse (4 g l(-1)) was added for all experiments after 48 h of fermentation. Results revealed that when using 0.90 g l(-1) of caffeine and 0.14 g l(-1) of ammonium sulphate, biomass production and caffeine degradation were enhanced. Highest biomass production (X-max = 9.87 g l(-1)) with a specific growth rate (mu) of 0.073 h(-1) and caffeine degradation rate of 0.033 g l(-1) h(-1), was observed under these conditions. Conclusions: Caffeine degradation as well as biomass production were characterized. Significance and Impact of the Study: These studies set the stage for future characterization studies of intracellular enzymes involved in caffeine degradation. Moreover, results observed may help in the biotreatment of residues from the coffee agroindustry.