Statistical Approaches for Optimization of Medium Components for Fungal Phytase

There are several strategies employed to increase the production of fungal enzymes, including
fermentation approaches, medium optimization, strain improvements, etc. In this chapter, we are
describing an ideal condition based on statistical approach to increase the phytase production from
heat stressed Rhizopus oryzae. The cost effective fermentation process is primarily based on medium
optimization, which helps in increasing the production of biomolecules. For the production of phytase
by heat stressed R. oryzae in submerged fermentation, we used Plackett-Burman design (PBD),
initially adopted for evaluating the medium components (mannitol, K2HPO4, Na2HPO4 and sodium
phytate) affecting the phytase production most. The optimum levels were estimated by central
composite design (CCD) of response surface methodology (RSM). The interactive effects of
phosphorus sources on phytase yield were determined to be significant. Application of Genetic
Algorithm (GA)/Nelder-Mead downhill simplex (NMDS) with RSM model was proved to be more
efficient approach for optimization of phytase production by Rhizopus oryzae. A 7.95-fold increase in
phytase production (12640 ± 1450 Ul-1) was achieved at the GA-predicted optimum concentration of
(gl-1); mannitol 22.8, K2HPO4 5.18, Na2HPO4 3.25, and sodium phytate 9.68, compared with the
phytase yield before optimization (1589 ± 135 Ul-1). In the bioreactor studies, the enzyme yields were
sustainable to that of the shake flask; however, the time required for maximum phytase production
was significantly reduced (288h to 96h), resulting in an increase in productivity by 3.32-fold.