• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1004-1008
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• 2004

An extracellular acid phytase from Pseudomonas fragi Y9451 was purified to homogeneity from the culture supernatant by salting-out, DEAE-Sepharose column chromatography, CM-Sepharose column chromatography, and Sephacryl S-300 gel filtration. The molecular weight of the purified enzyme was estimated to be 74 kDa on gel filtration and 54 kDa and 25 kDa on SDS-PAGE, suggesting that the native enzyme was a heterodimeric protein. The purified enzyme was most active at pH 4.5 and $70^{\circ}C$ and fairly stable from pH 4.0- 6.0. It was specific for phytate and exhibited a $K_{m}$ value of 27 mM (sodium phytate, pH 4.5, $50^{\circ}C$). The phytase activity was strongly inhibited (at maximum by 87%) by $Fe^{3+},\;Cu^{2+},\;Fe^{2+}$, and $Zn^{2+}$ at 5 mM concentration, and greatly inhibited by $Ca^{2+}$ at 10 mM concentration. However, EDTA notably stimulated the phytase activity at 10 mM concentration. With optimum pH and stability, Pseudomonas fragi phytase could be a potential candidate for animal feed applications.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.4
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• pp.627-632
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• 2013

High levels of an extracellular phytase were isolated from kimchi and found to be produced from a bacterial strain of Lactobacillus sakei (designated as L. sakei Wikim001). Phytase activity was measured from liberated inorganic phosphate obtained by a modification of the ammonium molybdate method using brown rice. Phytase activity was also detected in the culture broth supernatant at the stationary phase. The highest levels of phytase activity from L. sakei Wikim001 were detected at pH 5.0~6.5 and $30{\sim}40^{\circ}C$.

• Microbiology and Biotechnology Letters
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• v.34 no.1
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• pp.28-34
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• 2006

A native extracellular acid phosphatase, phytase (EC 3.1.3.8), from Bacillus coagulans IDCC 1201 (commercially known as Lactobacillus sporogenes) used as probiotics, was characterized. Though some strains of B. coagulans have been evaluated with regard to several health-promoting effects, it has not been reported to produce phytase. Partially purified phytase front the strain IDCC 1201 had a pH optimum of 4.0 and a temperature optimum of $50^{\circ}C$, respectively. The requirement for divalent cations was studied and cobalt ion remarkably increased the enzyme activity. The removal of metal ions from the enzyme by EDTA decreased activity below 50%. The enzyme activity depleted restored when the assay was performed in the presence of $Co^{2+}$. Also, $Co^{2+}$ is the most active stimulator and has unique activation effect at high temperature. The phytase was specific for sodium phytate and p-nitrophenylphosphate, which is different from other known Bacilli phytases. The putative amino acid sequences of the phytase from B. coagulans IDCC 1201 were very similar to that of the phytase from B. subtilis strain 168. Based on these data, we concluded that the phytase from B. coagulans IDCC 1201 is a $Co^{2+}$-dependent acid phosphatase. Therefore, the strain B. coagulans IDCC 1201 is thought to be a valuable addititive for livestocks as well as a beneficial probiotics for human.

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.745-748
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• 2005

A phytase from Aeromonas sp. LIK 1-5 was partially purified by ammonium sulfate precipitation and DEAE-Sephacel column chromatography. Its molecular weight was 44 kDa according to SDS-PAGE gel. Enzyme activity was optimal at pH 7 and at $50^{\circ}C$. The purified enzyme was strongly inhibited by 2 mM EDTA, $Zn^{2+},\;Co^{2+},\;or\;Mn^{2+}$, and activated by 2 mM $Ca^{2+}$. The K_m value for sodium phytate was 0.23 mM, and the enzyme was resistant to trypsin. The N-terminal amino acid sequence of the phytase was similar to that of other known alkaline phytases. The phytase was specific for ATP and sodium phytate, which is different from other known alkaline phytases. Based on the substrate specificity, the phytase may therefore be a novel alkaline phytase.

• Journal of Microbiology and Biotechnology
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• v.9 no.2
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• pp.223-226
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• 1999

A bacterial strain producing high level of an extracellular phytase was isolated from cooked rice and identified as a strain of Bacillus sp. and designated as Bacillus sp. KHU-10. Optimum culture conditions were investigated for the maximum productivity of phytase by Bacillus sp. KHU-10. 1.0% Maltose and 1.0% peptone with 0.5% beef extract were the best carbon source and nitrogen source, respectively. The addition of $CaCl_2$, stimulated the enzyme productivity with concentration between 0.01% and 0.2%, in the medium. Although sodium phosphate increased the cell mass, the enzyme activity decreased. Calcium phytate and wheat bran containing phytate did not enhance the enzyme production. Under the optimum medium, the production of the phytase reached the highest level of 0.2 unit/ml after 4 days of incubation.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.291-298
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• 2003

A bacterial strain producing a high level of an extracellular phytase was isolated from livestock waste water, identified as a strain of Pseudomonas fragi and designated as Pseudomonas fragi Y9451. Under the phytase production medium, the activity of phytase reached the highest level after 120 hours of incubation. On the effect of carbon sources on the phytase production, the most favorable carbon source for phytase production was fructose. As for the effect of nitrogen sources, high levels of phytase activity were detected in the medium containing nutrient broth as the nitrogen source. Free $PO_4^{3-}$ inhibited phytase production with increasing concentration of $KE_2PO_4$ and phytate in the media. The addition of $CaCl_2$ and $MgSO_4$ also resulted in the inhibition of phytase production. To investigate the effect of aeration on the phytase production, different volumes of culture broth in Erlenmeyer flasks were incubated in rotary shaker at the speed of 200 rpm. As a result, a high level of phytase activity was detected at small volume of culture broth as compared to larger volume because of its more aerobic condition.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.133-144
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• 1982

The distribution of acid phosphatase activity was investigated with 141 microorganisms from the type culture collection of Chong Kun Dang laboratory and the 41 strains isolated from natural sources. The phytase activity was detected mainly with fungal strains. A fungus isolated from soil and identified as Aspergillus niger had shown the highest phytase activity. The environmental conditions for the enzyme formation by the isolate and some properties of the enzyme were also studied. The results obtained were as follows: (1) The highest phytase production was observed when the fungus was cultivated at 28$^{\circ}C$ for 5 days in the corn starch based medium using the cells incubated at 34$^{\circ}C$ for 3 days as a seed. (2) The optimal initial pH of the culture medium was found to around 2 for the formation of phytase. (3) Sucrose was proved to be one of the most effective carbon sources tested for the enzyme production. (4) As an inorganic nitrogen source, potassium nitrate was found to give a good result in the production of phytase. (5) Synthesis of phytase was significantly increased by the supplement with 0.2 % corn steep liquor to the basal medium as an organic nitrogen source. (6) At the concentration of 40-80 mg inorganic phosphate per liter of the culture medium, the enzyme formation revealed the highest level. But as the phosphate was increased above this optimum concentration the phytase activity was drastically decreased although the cell density showed to be still increasing