Biodegradation of dibutyl phthalate in liquid fermentation by endophytic Penicillium species and the toxicity evaluation of the by-product

Abstract

The production and use of dibutyl phthalate (DBP) are increasing, and the resulting health and environmental problems are of concern. Therefore, the present study focused on the biodegradation of DBP in liquid fermentation using endophytic Penicillium species and evaluated the cytotoxic, ecotoxic, and phytotoxic effects of the fermented filtrate (by-product). Higher biomass yield was observed in fungal strains grown in DBP-containing media (DM) compared to DBP-free (control) media (CM). The highest esterase activity was observed at 240 h during fermentation with Penicillium radiatolobatum (PR) grown in DM (PR-DM). As per gas chromatography/mass spectrometry (GC/MS) results, the PR degraded 99.986 % of DBP after 288 h of fermentation. Furthermore, compared to DM treatment, the fermented filtrate of PR-DM demonstrated negligible toxicity in HEK-293 cells. Besides, the treatment of PR-DM in Artemia salina indicated >80 % viability and showed a trivial ecotoxic effect. However, compared to the control, the fermented filtrate of PR-DM treatment resulted in ~90 % of the roots and shoots growth of Zea mays seeds, indicating no phytotoxicity. Overall, the findings of this study suggested that PR can degrade DBP in liquid fermentation without generating toxic byproducts.