Identification of novel pathways for biodegradation of bisphenol A by the green alga Desmodesmus sp.WR1, combined with mechanistic analysis at the transcriptome level

- Desmodesmus sp. is highly tolerant of BPA.
- BPA degradation occurs via hydroxylation, glycosylation, and cleavage.
- New metabolites and degradation pathways were reported.
- Oxidoreductase and glycosyltransferase transcripts are upregulated on BPA exposure.

The effects of bisphenol A (BPA) on the growth and photosynthetic activity of green alga Desmodesmus sp.WR1 were investigated, as well as its detoxification and biodegradation by this algal species. Transcriptome profiling analysis was employed to elucidate the molecular response of Desmodesmus to BPA exposure. None of the BPA exposure levels tested (1, 3, 5.5, 13.5 mg L−1) significantly inhibited growth of Desmodesmus sp.WR1, and 57%, 25%, 18% and 26% of BPA were removed by this algal culture, respectively. The BPA metabolites monohydroxybisphenol A glycoside, 2-hydroxy-3-hydroxymethybisphenol A and its glycosides, and their monophenol products were identified for the first time as being generated from oxidative hydroxylation, glycosylation, and oxidative cleavage, respectively. Transcriptome analysis showed that algae significantly upregulated oxidoreductase- and glycosyltransferase-encoding genes for BPA oxidative biodegradation and addition of glycosyl groups for detoxification. This study suggests that the Desmodesmus sp.WR1 could be suitable for BPA removal from contaminated aquatic environments.