Heterologous expression and characterization of a bilirubin oxidase gene from Myrothecium verrucaria in Arabidopsis thaliana

Bilirubin oxidases (BODs), which catalyze the oxidation of bilirubin to biliverdin, are multi-copper oxidases that can be used in clinical diagnoses. Given their different reported enzymatic characterizations from laccases, BODs have gained considerable attention for their application in healthcare and environment management. In this study, a BOD gene from Myrothecium verrucaria was chemically synthesized and optimized to heterogeneous expression in Arabidopsis thaliana. The optimized DNA sequence showed 80.1% similarity to the original sequences. The gene was successfully transferred into A. thaliana, and the crude extracts of transgenic plants showed higher BOD activity compared with that of untransformed plants. BOD expressed in transgenic A. thaliana also exhibited an activity on the typical substrate (ABTS) of laccase and was able to decolorize the textile dyes crystal violet and malachite green. The results indicated that the M. verrucaria BOD gene could be transgenically exploited in plants for dye decolorization.