ENHANCEMENT OF INVERTASE PRODUCTION BY Aspergillus niger OZ-3 USING LOW-INTENSITY STATIC MAGNETIC FIELDS

Abstract

The aim of this study is to investigate the effect of low-intensity static magnetic fields (SMFs) on invertase activity and growth on different newly identified molds. The most positive effect of SMFs on invertase activity and growth was observed for Aspergillus niger OZ-3. The submerged production of invertase was performed with the spores obtained at the different exposure times (120, 144, 168, and 196 hr) and magnetic field intensities (0.45, 3, 5, 7, and 9 mT). The normal magnetic field of the laboratory was assayed as 0.45 mT (control). Optimization of magnetic field intensity and exposure time significantly increased biomass production and invertase activity compared to 0.45 mT. The maximum invertase activity (51.14 U/mL) and biomass concentration (4.36 g/L) were achieved with the spores obtained at the 144 hr exposure time and 5 mT magnetic field intensity. The effect of low-intensity static magnetic fields (SMFs) on invertase activities of molds was investigated for the first time in the present study. As an additional contribution, a new hyper-invertase-producing mold strain was isolated.

Supplemental materials are available for this article. Go to the publisher's online edition of Preparative Biochemistry and Biotechnology to view the supplemental file.

Keywords:

• Aspergillus niger OZ-3
• invertase
• static magnetic field
• submerged culture

Notes

Note. All values are the means ± standard error of six determinations (n = 6). Values with the same superscripted letters in the same column are not significantly different (p < 0.05). Production medium composed of (g/L) 20 sucrose and 3 peptone (pH 6.0). Culture conditions: shaking speed = 200 rpm, temperature = 30°C, incubation time = 60 hr. The experiments were performed with the spores obtained at different static magnetic fields (SMFs) for 168 hr exposure time. MFI, magnetic field intensity; BC; biomass concentration; IA, invertase activity.

Note. All values are the means ± standard error of six determinations (n = 6). Values with the same superscripted letters in the same column are not significantly different (p < 0.05). Production medium composed of (g/L) 20 sucrose and 3 peptone (pH 6.0). Culture conditions: shaking speed = 200 rpm, temperature = 30°C, incubation time = 60 hr. MFI, magnetic field intensity; ET, exposure time; BC; biomass concentration; BCI, biomass concentration increase; IA, invertase activity; IAI, invertase activity increase.

Note. All values are the means ± standard error of six determinations (n = 6). Values with the same letters in the same column are not significantly different (p < 0.05). Production medium composed of (g/L) 20 sucrose and 3 peptone (pH 6.0). Culture conditions: shaking speed = 200 rpm, temperature = 30°C. The experiments were performed with the spores obtained at 144 hr exposure time. IT, incubation time; MFI, magnetic field intensity; BC; biomass concentration; IA, invertase activity.