Novita Kurniawati
Animal Products Technology, Faculty Of Animal Science, Universitas Gadjah Mada, Yogyakarta, 55281, Indonesia

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Biosorption of Metal Ions on Methanol Dehydrogenase Enzymatic Activity of Bradyrhizobium japonicum USDA110 Novita Kurniawati; Ambar Pertiwiningrum; Yuny Erwanto; Nanung Agus Fitriyanto; Mohammad Zainal Abidin
Buletin Peternakan Vol 42, No 2 (2018): BULETIN PETERNAKAN VOL. 42 (2) MAY 2018
Publisher : Faculty of Animal Science, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21059/buletinpeternak.v42i2.26195

Abstract

This research aims to understand the effect of metal ions bioabsorption which belong on different elemental groups to the methanol dehydrogenase (MDH) enzymatic activity in nitrogen-fixing bacteria Bradyhizobium japonicum USDA 110. Ten metal ions with each have 30μM concentration were added to grow Bradyhizobium japonicum USDA 110 in 10-1 diluted nutrient medium. The MDH activity test showed a similar result between the bacteria grown in medium without metal ions addition (control) and the bacteria were grown in a calcium ion/Ca2+ added media. The highest MDH enzymatic activity was shown on the bacteria grown in a magnesium/Mg2+ added medium, which showed 0.08 (U/mg) enzymatic activities. The addition of magnesium/Mg2+ metal ion accelerates the bacterial growth by 2.6 times and MDH activity by 1.28 times compared to control. The MDH enzyme is essential, especially for bacteria which exist in the soil environment, to adapt to high methanol concentration and to support bacterial anaerobic growth capacity along with plant symbiotic process. Moreover, the MDH activity staining method could also act as pollutant indicators like metal ions and hydrocarbon derivates. This research concluded that metal ions biosorption (calcium/Ca2+ and magnesium/Mg2+) are required for bacterial cells reproduction and oxidation of single carbon chain compounds like methanol. The nitrogen-fixing symbiotic bacteria, Bradyhizobium japonicum USDA 110 showed high MDH activity after the two metal ions absorption. However, contrary results were shown on vanadium/V3+, manganese/Mn2+, iron/Fe3+, copper/Cu2+, zinc/Zn2+, and aluminum/Al3+ absorption, which showed low MDH activity and cells biomass.
Direct Stimulation by Methanol Addition on the Cultured Medium for Methanol Dehydrogenase Protein Purification from Bradyrhizobium japonicum USDA110 Novita Kurniawati; Ambar Pertiwiningrum; Yuny Erwanto; Nanung Agus Fitriyanto; Mohammad Zainal Abidin
Buletin Peternakan Vol 42, No 3 (2018): BULETIN PETERNAKAN VOL. 42 (3) AUGUST 2018
Publisher : Faculty of Animal Science, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21059/buletinpeternak.v42i3.28155

Abstract

Methanol dehydrogenase (MDH) enzyme was purified from Bradyrhizobium japonicum USDA110 cell-free extract. The bacteria were grown in a culture medium with direct 0.5% methanol addition aimed to stimulates the MDH catalytic enzyme activation. Bradyrhizobium japonicum USDA110 MDH enzyme was purified by using 25 mM 2-(N-morpholine) ethanesulfonic acid/MES pH 5.5 buffer and 1 M sodium chloride/NaCl which separated into three columns, the first column was PD-10 for buffer exchange; the second column was HiTrap Sepharose HP to obtain unbonded fraction in the column; and the third column was Mono S 5/50 GL integrated with two pumps HPLC (high-performance liquid chromatography) to obtain pure MDH enzyme for serial changing of 1 M NaCl-25mM MES pH 5.5 with the flow rate at 1 ml/min. The protein concentration and MDH catalytic enzyme activity were observed on each purification process starting from the cell-free extract to pure MDH enzyme. The pure MDH enzyme was obtained by Mono S 5/50 GL-HPLC purification which showed a single band on SDS PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). The MDH enzyme purification from Bradyrhizobium japonicum USDA110 showed 90-fold purification, a sub-molecular weight of 63 kDa, specific activity at 2.69 U/mg, and optimum activity at a 35oC temperature and pH 9.