RESUMEN
This study evaluated the toxicity and cellular stresses of carbamazepine (CBZ) on Chlamydomonas mexicana and Scenedesmus obliquus, and its biodegradation by both microalgal species. The growth of both microalgal species decreased with increase of CBZ concentration. The growth of S. obliquus was significantly inhibited (97%) at 200 mg CBZ L(-1), as compared to the control after 10days; whereas, C. mexicana showed 30% inhibition at the same experimental conditions. Biochemical characteristics including total chlorophyll, carotenoid contents and enzyme activities (SOD and CAT) for both species were affected by CBZ at relatively high concentration. C. mexicana and S. obliquus could achieve a maximum of 35% and 28% biodegradation of CBZ, respectively. Two metabolites (10,11-dihydro-10,11-expoxycarbamazepine and n-hydroxy-CBZ) were identified by UPLC-MS, as a result of CBZ biodegradation by C. mexicana. This study demonstrated that C. mexicana was more tolerant to CBZ and could be used for treatment of CBZ contaminated wastewater.
Asunto(s)
Carbamazepina/metabolismo , Chlamydomonas/metabolismo , Microalgas/metabolismo , Scenedesmus/metabolismo , Contaminantes Químicos del Agua/metabolismo , Biodegradación Ambiental , Carbamazepina/farmacocinética , Carbamazepina/toxicidad , Carotenoides/metabolismo , Catalasa/metabolismo , Chlamydomonas/efectos de los fármacos , Chlamydomonas/crecimiento & desarrollo , Clorofila/metabolismo , Agua Dulce , Microalgas/efectos de los fármacos , Scenedesmus/efectos de los fármacos , Scenedesmus/crecimiento & desarrollo , Especificidad de la Especie , Superóxido Dismutasa/metabolismo , Aguas Residuales/química , Contaminantes Químicos del Agua/farmacocinética , Contaminantes Químicos del Agua/toxicidadRESUMEN
Two freshwater microalgae including Chlamydomonas mexicana and Scenedesmus obliquus were grown on Bold Basal Medium (BBM) with different levels of salinity up to 100 mM NaCl. The dry biomass and lipid content of microalgae were improved as the concentration of NaCl increased from 0 to 25 mM. Highest dry weight (0.8 and 0.65 g/L) and lipid content (37 and 34 %) of C. mexicana and S. obliquus, respectively, were obtained in BBM amended with 25 mM NaCl. The fatty acid composition of the investigated species was also improved by the increased NaCl concentration. At 50 mM, NaCl palmitic acid (35 %) and linoleic acid (41 %) were the dominant fatty acids in C. mexicana, while oleic acid (41 %) and α-linolenic acid (20 %) were the major fractions found in S. obliquus.