*Department of Microbiology, JBAS College for Women, Teynampet, Chennai, Tamil Nadu, India
**Department of Microbiology, Kanchi Shri Krishna College of Arts and Science, Kilambi, Kanchipuram-631551, Tamil Nadu, India
***Research and Development Centre, Bharathiar University, Coimbatore, Tamil Nadu, India
Online published on 5 May, 2016.
Caffeine (1, 3, 7-trimethylxanthine), a purine alkaloid occurs in more than 60 plant species including in the seeds of coffee, cacao, cola tree and in the leaves of tea (Ashihara and Crozier, 2001). Concerned with the deleterious effects of potential chronic ingestion of caffeine on the physiological systems(higher than 150mg/day), decaffeination is highly recommended in both coffee processing and disposal of coffee spent.
Conventional decaffeination techniques like solvent extraction or use of supercritical carbon dioxide can be expensive, toxic to the environment and non-specific. So there is a strong need for caffeine degradation by alternative routes other than conventional techniques. The potential use of microbes and their enzymes is an attractive alternative as it is cheap, easier and faster. (Mazzefera et al., 2002). The present study aims in optimizing physical parameters and media for maximum degradation of caffeine by the selected isolate Brevibacterium.
Harnessing the caffeine degrading potential of organisms growing in caffeine rich soil is of importance in developing processes for biodecaffeination and production of methylxanthine intermediates which have therapeutic value.
The present investigation mainly deals with the Optimization of media and its main components viz., effect of Carbon source and Nitrogen Source to achieve maximum biodegradation of caffeine by the selected isolate Brevibacterium isolated and maintained in our laboratory. The growth and caffeine degradation were recorded as the increase in biomass by weight and residual caffeine analysis of the samples by HPLC respectively.
Brevibacterium was grown in the optimized growth medium containing sucrose (10 g. L-1), caffeine (2 g. L-1), yeast extract (15 g. L-1), peptone (30 g. L-1) and ammonium sulphate (15 g. L-1). The temperature of the medium was set at 35oC, and pH adjusted to 7.0 and an inoculum of 7%w/v was added to the medium and incubated by shaking at 150rpm for 96 hrs. Under these conditions, 9.6 g. L-1 of biomass was accumulated after 96 hrs with a growth rate of 0.031 g. L-1.h-1. Caffeine was almost completely (99.8%) degraded within 60 hrs of incubation. High caffeine degradation rates were observed under these conditions. The caffeine degradation rate was 0.034 g. L-1.h-1. Under optimized conditions the acclimatization time for caffeine was reduced to 24hrs and around 50%.
