Journal of Environmental Biology

Application of response surface methodology for optimising

caffeine-degrading parameters by Leifsonia sp. strain SIU

Salihu Ibrahim^1,2, Mohd Yunus Shukor¹, Khalilah Abdul Khalil³, Mohd Izuan Effendi Halmi¹, Mohd Arif Syed¹ and Siti Aqlima Ahmad¹*

¹Department of Biochemistry, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia

²Department of Biochemistry, Faculty of Biomedical Sciences, Bayero University, PMB 3011 Kano, Nigeria

³Biomolecular Science Program, School of Biology, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia

*Corresponding Author E-mail : aqlima@upm.edu.my

Publication Data

Paper received:

17 June 2014

Revised received:

12 March 2015

Accepted:

20 March 2015

Abstract

Caffeine is an important naturally occurring compound which can be degraded by bacteria. Previously, Leifsonia sp. strain SIU capable of degrading caffeine was isolated from agricultural soil.? Plackett?Burman design was used to screen significant parameters that affect the rate of caffeine degradation. After the design was applied, response surface methodology (RSM) through Central Composite Design (CCD) was used to study significant parameters further, in order to get the most superior degradation conditions. The optimum concentrations of carbon source (sucrose), nitrogen source (NH₄Cl), pH and initial caffeine concentration was found to be 5.0 gl^-1, 0.4 gl^-1, 6.0 and 375 ppm respectively. Second order polynomial regression model accurately showed interpretation of experimental data with an R² value of 0.9989, Adjusted (Adj) R², Predicted (Pred) R² and F values of 0.9939, 0.9225 and 88.77 respectively. ?   

 Key words

Caffeine degradation, Central composite design, Leifsonia sp., Plackett-Burman Design, Response surface methodology

Copyright ? 2015 Triveni Enterprises. All rights reserved. No part of the Journal can be reproduced in any form without prior permission. Responsibility regarding the authenticity of the data, and the acceptability of the conclusions enforced or derived, rest completely with the author(s).