Effect of Radionuclides and Trace Elements on Antioxidant System of Brown Seaweeds.

Ecological effects in marine living can be understood via the determination of antioxidant molecules in aquatic organisms against pollutants. This study aims to evaluate the radionuclides and trace element stress with response molecules. Cystoseira crinita and Halopteris scoparia have been chosen as study materials because of their susceptibility to pollution. The radionuclides 210Po, 238U, 232Th and 40K and trace elements Al, Fe, Mn, Cr, As, Zn and Pb levels were analysed as well as antioxidants and antioxidant enzymes in two brown algae, seasonally. Marine pollutants in terms of radionuclides and trace elements were correlated with antioxidant molecules in these species and may be used as biomarkers for assessing the radioactive stress. The 210Po and Mn concentrations in C. crinita seem to activate catalase (CAT) and superoxide dismutase (SOD) enzyme activities while 210Po concentrations inclined the proline amount in H. scoparia. This study demonstrated the radiation stress-induced the antioxidant defence system in macroalgae, the primary producers of the marine environment.

Study of silanized nanostructures with immobilized fumarase for production of L-malate.

The conversion of fumaric acid into L-malate by fumarase immobilized on silanized nanostructures was analyzed experimentally. The enzyme was bound to the silanized nanostructures. We carried out scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR) analysis, zeta size analysis and surface area calculation for the characterization of the nanostructures. The effect of initial enzyme concentration and pH on immobilization procedure were investigated and the change of Michaelis-Menten constants (Km and Vmax) with immobilization was examined. The change in the storage stability of the enzyme by immobilization was also investigated. The stability of the immobilized enzyme was very good. We observed that the fumarase was bound to silanized nanostructures [p(HEMA)-3-MTES] in much greater amounts. We have compared the activities of free fumarase and immobilized fumarase and we have observed a significant increase in the activity of the fumarase after immobilization for L-malate production. Moreover, we came to the conclusion that this activity can be better preserved for 30 days compared to free fumarase.