Effect of the nitrogen source on caffeine degradation by Aspergillus tamarii.

Abstract

To evaluate caffeine degradation and nitrogen requirements during Aspergillus tamarii growth in submerged culture. 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 (Xmax = 9.87 g l-1) with a specific growth rate (micro) of 0.073 h-1 and caffeine degradation rate of 0.033 g l-1 h-1, was observed under these conditions. Caffeine degradation as well as biomass production were characterized. 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.