RESUMEN
Cyanobacterial blooming due to the influence of temperature and increased nutrients in ponds/lakes aided by the runoff from agricultural lands, is a serious environmental issue. The presence of cyanotoxins in water may poison the health of aquatic organisms, animals, and humans. In this study, we focus on chemical assisted degradation of Microcystis aeruginosa- an alga that is of special relevance owing to its consistent blooming, especially in tropical regions. The study aims to ascertain the individual iodine (I) and hydrogen peroxide (H2O2) and their combination (hereinafter referred to as IH) effects on the degradation of Microcystis aeruginosa. As expected, the collected pond water revealed the presence of metal ions viz., Ni, Zn, Pb, Cu and Mn, which enriched the blooming of M. aeruginosa. Interestingly, a complete rupture of the cells - pigment loss, biochemical degradation and oxidative damage-was observed by the IH solution after exposure for â¼9 h under ambient conditions. In comparison to control (original water without chemicals), the addition IH completely eliminated the pigments phycocyanin (99.5%) and allophycocyanin (98%), and degraded â¼81% and 91% of carbohydrates and proteins, respectively due to the synergistic action of I and H. Superior degradation of algae through a simple and eco-friendly approach presented in this study could be explored more effectively towards its large-scale applicability.
RESUMEN
The effects of Indole-3-butyric acid (IBA) supplementation in combination with nitrogen limitation on the biomass, biochemical and fatty acid composition of three selenastracean microalgae were studied. In the algae tested, nitrogen deficiency alone resulted in lower biomass output, whereas supplementation with 0.075 mM IBA resulted in increased biomass production on Selenastrum capricornutum (679 mg L-1), Ankistrodesmus falcatus (521 mg L-1) and Kirchneriella obesa (361 mg L-1) than their respective controls. The chlorophyll content of the algae showed a negative correlation with IBA dosage. Whilst it could significantly stimulate carotenoid biosynthesis in S. capricornutum and nitrogen limited (NL) alone, it influenced carotene production in both A. falcatus and K. obesa. Among the treatments, NL+ 0.075 mM IBA markedly increased the total lipid content to 1.2-fold in S. capricornutum, 0.81-fold in A. falcatus and 0.35-fold in K. obesa, with higher lipid productivity than control. NL+ 0.05 mM IBA significantly increased the amount of saturated fatty acids and NL+ 0.075 mM IBA significantly increased the amount of unsaturated fatty acids in all members of the Selenastraceae family under study. Thus, the study promises the importance of Selenastraceae members as a valuable feedstock for various process industries.
Asunto(s)
Microalgas , Biomasa , Ácidos Grasos , Indoles , Lípidos , NitrógenoRESUMEN
In this investigation, we report on the treatment of tannery wastewater using microalgae Chlorella species to produce lipid and fatty acid as well as changes in antioxidant metabolism during the treatment. The variation in growth, production of pigments, antioxidant metabolism, lipid and fatty acids, and nutrient removal from wastewater during the remediation were observed. Surprisingly, a profuse growth was found in 50% diluted tannery wastewater (TW), which supported to accumulate high yield of lipid (18.5%) and unsaturated fatty acids (50.05%). The antioxidant activity of microalgae in both the concentrations (50% and 100% TW) were viz., lipid peroxidation 1.6 ± 0.1 and 2.3 ± 0.02nmol MDA mg-1 protein, SOD 10.3 ± 0.4 and 15.7 ± 0.9 U mg-1 protein, CAT 0.17 ± 0.036 and 0.52 ± 0.06 U mg-1 protein, and APX 7.2 ± 0.8 and 11.2 ± 09 U mg-1 protein respectively, which point out that the free radical scavenging mechanism against heavy metal stress. Maximum phycoremediation of heavy metals observed from both concentrations during the healthy growth period were Cr - 73.1, 45.7%, Cu - 90.4, 78.1%, Pb - 92.1, 52.2%, and Zn - 81.2, 44.6%, respectively. This study proved the potential use of Chlorella for heavy metal and nutrient removal from tannery wastewater. Moreover, an unaffected growth with high antioxidant activity of this species promises a sustainable lipid and fatty acid contents for biofuel production.