Production and partial characterization of two types of phytase from Aspergillus niger NCIM 563 under submerged fermentation conditions

Abstract

Novel extracellular phytase was produced by Aspergillus niger NCIM 563 under submerged fermentation conditions at 30°C in medium containing dextrin and glucose as carbon sources along with sodium nitrate as nitrogen source. Maximum phytase activity (41.47 IU/mL at pH 2.5 and 10.71 IU/mL at pH 4.0) was obtained when dextrin was used as carbon source along with glucose and sodium nitrate as nitrogen source. Nearly 13 times increase in phytase activity was observed when phosphate in the form of KH 2 PO 4 (0.004 g/100 mL) was added in the fermentation medium. Physic-chemical properties of partially purified enzyme indicate the possibility of two distinct forms of phytases, Phy I and Phy II. Optimum pH and temperature for Phy I was 2.5 and 60°C while Phy II was 4.0 and 60°C, respectively. Phy I was stable in the pH range 1.5-3.5 while Phy II was stable in the wider pH range, 2.0-7.0. Molecular weight of Phy I and Phy II on Sephacryl S-200 was approximately 304 kDa and 183 kDa, respectively. Phy I activity was moderately stimulated in the presence of 1 mM Mg 2+ , Mn 2+ , Ca 2+ and Fe 3+ ions and inhibited by Zn 2+ and Cd 2+ ions while Phy II activity was moderately stimulated by Fe 3+ ions and was inhibited by Hg 2+ , Mn 2+ and Zn 2+ ions at 1 mM concentration in reaction mixture. The Km for Phy I and II was 3.18 and 0.514 mM while Vmax was 331.16 and 59.47 lmols/min/ mg protein, respectively.

Optimization of Culture Conditions to Produce Phytase from <i>Aspergillus tubingensis SKA</i>

“…Results show that there were no significant differences in phytase activity among the treatments and control. Results reported by Soni et al [28] found that presence of Fe 2+ in the fermentation medium of Aspergillus niger NCIM 563 lead to a decreased phytase activity. In addition, Sreedevi and Reddy [30] found that the presence of Mg +2 , Mn +2 and K +1 in bacterial phytase production medium increased enzyme activity significantly.…”

“…This may be referred to the phenomenon of phosphate repression expressed on phytase production, which was observed clearly in fungal phytase as well as phytase produced from yeasts [27] [28]. As stated by Selvamohan et al [25], phosphates can act as both repressors and inducers of phytase production in different microorganisms.…”

Optimization of aqueous extraction process to enhance the production of phytase by Rhizopus oryzae using response surface methodology coupled with artificial neural network

“…The results clearly suggested that the low inorganic phosphorus substrate stimulates phytase synthesis and excess of inorganic phosphorus causes repression of phytase synthesis, although the presence of traces of inorganic phosphorus is an essential ingredient of phytase production medium and induces its production (Soni and Khire, 2007).…”

Strain improvement and up scaling of phytase production by Aspergillus niger NCIM 563 under submerged fermentation conditions

“…Earlier we have reported phytase production by A. niger NCIM 563 under solid-state and submerged fermentation conditions [2,16,23]. In the present studies we have successfully isolated hyper secretary mutants (N-1 and N-79) by combination of physical (UV) and chemical (EMS) mutagenesis with increase in productivity of parent strain from 6,181 IU/L per day (1,02,604 nKat/L per day) to mutant strain (N-79) to 9,523 IU/L/d (1,58,081 nKat/L/d).…”

“…Stabilization of phytase at room temperature and higher temperature was studied for its application in mash feed and pelleted feed. Earlier, we have reported phytase production under solid-state fermentation (SSF) [16] and submerged fermentation using dextrin-glucose medium [22,23] and various agriculture residues [2].…”