Selective caffeine removal by microbial consortia

Coffee processing presents a considerable waste disposal problem, mainly because of the large volumes generated and the chemical composition of the by-products, particularly the caffeine levels. The use of Pseudomonas putida IF-3, a caffeine-degrading microorganism, in a microbial consortium for bioremediation of caffeine found in coffee wastes was investigated. Caffeine degradation was observed in fed-batch reactor experiments with caffeine as sole source of carbon and nitrogen. Metabolic regulation and caffeine removal potential by Pseudomonas putida IF-3 were investigated by supplementing with other nutrient sources. Diauxic growth was not observed. Nitrogen release from caffeine breakdown was found to be rate-limiting.Effects of caffeine on microbial consortia were studied using denaturing gradient gel electrophoresis (DGGE), providing a community-scale view of changes in microbial consortia upon caffeine addition. Surprisingly, caffeine removal was achieved indigenously by the microbial consortium. Principal component analysis was used to analyze differences in DGGE banding patterns between control and caffeine-exposed mixed cultures