1. CINVESTAV-IPN, Dept. Biotechnology, Environmental Biotechnology R&D Group, P.O.Box 14-740, Mexico D.F., 07000, Mexico
2. TESE, Ecatepec Institute of Technology, Edo. de Mex., Mexico
3. ESIQIE-IPN, Division of Basic Science, Campus Zacatenco, Mexico D.F., Mexico