Biodegradation of bisphenol a and disappearance of its estrogenic activity by the green alga Chlorella fusca var. vacuolata

Abstract

Bisphenol A (BPA) is known as an endocrine disruptor and often is found in landfill leachates. Removal of BPA by green alga, Chlorella fusca, was characterized, because we previously found that various phenols were well removed by this strain, including BPA. Chlorella fusca was able to remove almost all BPA in the concentration range from 10 to 80 microM for 168 h under continuous illumination at 18 W/m2. At the low light intensity of 2 W/m2, 82% of 40 microM BPA was removed, and only 27% was removed in the dark. Moreover, C. fusca could remove 90% of 40 microM BPA under the 8:16-h light:dark condition, which was almost as high as that under the continuous-light condition. The amount of BPA contained in the cells was less than the amount of BPA removed from the medium. Monohydroxybisphenol A was detected as an intermediate of BPA degradation. Moreover, estrogenic activity that originated from BPA in the culture medium also completely disappeared. Based on these results, BPA was finally degraded to compounds having nonestrogenic activity. Therefore, C. fusca can be considered a useful organism to remove BPA from landfill leachates.

Cellular responses and bioremoval of nonylphenol and octylphenol in the freshwater green microalga Scenedesmus obliquus

“…This is consistent with the results of previous studies on the BPA removal by some microalgae species (Li et al, 2009;Hirooka et al, 2005;Nakajima et al, 2007), NP removal by Chlorella vulgaris and Selenastrum capricornutum and OP removal by Microcystis aeruginosa (Baptista et al, 2009). After adsorption and absorption, the target compounds NP and OP were first accumulated and then metabolized by algal cells; thus the amounts of NP and OP accumulated in algal cells were much less than the amounts biodegraded.…”

“…Tsang et al (1999) reported that Chlorella vulgaris resisted tributyltin (TBT) by transforming TBT into a much less toxic metabolite. Some microalgae species such as Chlorella fusca can metabolize BPA to an intermediate with no estrogenic activity (Hirooka et al, 2005;Nakajima et al, 2007). Microcystis aeruginosa also coped with OP toxicity by internalizing the compound to a probably less toxic form (Baptista et al, 2009).…”

Phytodecontamination of Water Systems from Phenolic Endocrine Disruptors and the Regulation Role of Natural Organic Matter

“…Generally, after 2 and 4 days BPA at lower concentrations was not toxic for the alga, whereas at the highest concentration it reduced algal growth and photosynthetic efficiency. A similar growth response was shown by the marine diatom Stephanodiscus hantzschii [57] and the green alga Chlorella fusca [58] which showed an evident toxicity at BPA concentrations equal or higher than 5 mg L -1 and 9 mg L -1 , respectively. The sole NOM and its combinations with bisphenol A at the lower concentrations increased the cell number and the chlorophyll a content of algae, whereas all combinations between BPA at highest concentration and NOM resulted very toxic for the algae.…”

Biotransformation of progesterone and norgestrel by two freshwater microalgae (Scenedesmus obliquus and Chlorella pyrenoidosa): Transformation kinetics and products identification

“…It is known that like bacteria and fungi, algae are able to remove organic contaminants via adsorption, absorption and degradation processes (Hirooka et al, 2005;Nakajima et al, 2007;Li et al, 2009;Gao and Tam, 2011). The objectives of this study are to assess the biotransformation potential of two progestogens (progesterone and norgestrel) by two widely distributed freshwater green microalgae Scenedesmus obliquus and Chlorella pyrenoidosa, and to investigate their algal transformation mechanisms and transformation products.…”