Chemotaxis of Pseudomonas sp. to caffeine and related methylxanthines.

Pseudomonas sp. isolated from soil of coffee plantation area has been shown to degrade higher concentrations of caffeine ( approximately 15 g l(-1)) by N-demethylation at a rate higher than what has been reported for any strain so far. This strain exhibits positive chemotaxis towards caffeine (1,3,7-trimethylxanthine) in swarm plate assay and modified capillary assay in a dose dependant manner. Related methylxanthines and xanthine also act as chemoattractants for the strain with the highest relative chemotactic response (RCR) seen for xanthine. Chemotaxis in Pseudomonas sp. is possibly plasmid mediated as indicated by positive chemotaxis of plasmid transformed E. coli DH5alpha. The chemotactic abilities of Pseudomonas sp. combined with higher rates of degradation of caffeine can be used in the development of strategies for biodecaffeination of caffeine containing wastes.