Statistical modeling and optimization of microbial phytase production towards utilization as a feed supplement

Abstract

The current study aimed to achieve the enhanced phytase production from Aspergillus niger NT7 using the statistical method in solid-state fermentation to diminish their cost significantly for commercial purposes. The six different variables — the substrate’s amount, temperature, incubation time, pH, the concentration of mannitol, and ammonium sulfate — identified as critical parameters from the one variable at a time (OVAT) approach, were further modeled and optimized in solid-state fermentation using response surface methodology (RSM). Increased phytase production (521 ± 28.16 Ugds− 1) by RSM was attained with 5-g wheat bran supplemented with 2% mannitol, 0.5% ammonium sulfate, and pH 4.3 at 35 °C after five days of fermentation. The phytase production was enhanced by 6.8- and 2.5-fold after statistical optimization compared to unoptimized culture conditions and OVAT methodology, respectively. Further, dephytinization of maize bran using crude phytase preparation resulted in ameliorated nutritional status with the release of phosphorous, reducing sugars, proteins, and minerals (Mn, Fe, Mg, Zn, and Ca). To the best of our knowledge, this is the first report showing the nutritional enhancement of maize bran and the analysis of released minerals by ICP-MS using crude enzyme preparation. The current study successfully demonstrates the potential application of A. niger NT7 phytase for mitigating the antinutrient nature of phytate molecules in feed supplementation.