Effects of magnetic field on the antioxidant defense system of recirculation‐cultured Chlorella vulgaris

Abstract

Little is known about the influence of magnetic fields (MF) on growth of microalgae such as Chlorella vulgaris, which has been consumed as health food for various nutritional and pharmacological effects. This preliminary study investigated whether static MF can modulate the antioxidant system in C. vulgaris by exposing the cells to static MF generated by dual yoke electromagnets with magnetic flux density of 10-50 mT for 12 h. After exposure to 10-35 mT for 12 h, the activity of superoxide dismutases and peroxidase increased significantly compared to control cells. However, a remarkable increase of catalase activity occurred at 45 and 50 mT. The lipid peroxidation of algae cells determined by production of thiobarbituric acid-reactive substances was much increased when exposed to 35, 45, and 50 mT of MF. The scavenging ability of 2,2-diphenyl-1-picrylhydrazyl radical was decreased markedly while there was no variation of total carotenoids content in C. vulgaris cells. Assay of specific growth rate in 72 h cultivation after MF exposure was also conducted. In groups after exposure to 10-35 mT of MF, specific growth rate was significantly increased. These results suggest that 10-35 mT of static MF exposure could promote the growth of C. vulgaris and regulate its antioxidant defense system to protect cells efficiently, which could possibly enhance the growth of C. vulgaris in industrialized cultivation by MF.

Effect of moderate static electric field on the growth and metabolism of Chlorella vulgaris

“…This hormetic response to EF was also observed during treatment of C. kessleri (Small, 2012) and C. vulgaris (Wang, 2008) cells with a static magnetic field. Gusbeth et al (Gusbeth, 2013) observed an increase of about 10-20% in biomass yield of C. vulgaris during 30 min treatment with low intensity pulsed electric field.…”

“…But at high treatment times, there are possibilities of irreversible electrical breakdown and free radical damage to the cells. The damage by the hydroxyl radicals can be neutralized by microalgae to an extent depending on the algal concentration (Wang, 2008). That is a possible explanation for a shift in the optimal treatment time from 30 min to 70 min with an increase in algal concentration from 0.25 g L -1 to 1.0 g L -1 .…”

“…In particular, physicochemical pretreatments have the potential to promote algal growth in open pond systems and to stimulate the synthesis of specific metabolites, without causing bacterial contamination. For example, Wang et al (Wang, 2008) studied the effect of static magnetic fields on the growth of C. vulgaris. They observed an increase of up to 68% in the growth rate of algal cells exposed to 10-35 mT for 12 h compared to a control.…”

Stimulation of growth and some biochemical parameters by magnetic field in wheat (Triticum aestivum L.) tissue cultures

“…An orientation on free radicals' spin conditions by external MF and the energy increase as a result of this orientation accelerate chemical reactions in cell (Aladjanjiyan and Ylieva, 2003). Reactive half life of free radicals which occur during metabolic activity of organism increase by the effect of MF and antioxidant defense mechanism act as a protection from deleterious effects of these radicals (Sahebjamei et al, 2007;Wang et al, 2008).…”

“…These increases were 80.39%, 73.45% and 62.32% for 19.8 s magnetic field applied experimental groups compared to the control, respectively. Various studies reported that MF increase enzyme activities of CAT, POX, and polyphenol oxidase (Lebedev et al, 1975;Pintilie et al, 2006;Wang et al, 2008).…”