“…Microbial biosensors based on the determination of the metabolic intermediate have not been reported for 2,4-D, while such a type of whole cell amperometric biosensors have been reported for p-nitrophenol (Lei et al, 2004;Mulchandani et al, 2005). A tyrosinase-modified electrode is one of effective transducers for phenols or catechols detection, for which active studies have been made on the development of highly efficient tyrosinase electrodes (for example, Notsu & Tatsuma, 2004;Mailley et al, 2004;Stanca & Popescu, 2004;Gutés et al, 2005;Carralero Sanz et al, 2005;Liu et al, 2005). Developments of flow injection analysis with tyrosinase electrode have been also attempted (Dall' Orto et al, 1999;Li & Tan, 2000;Notsu et al, 2002;Serra et al, 2003).…”