L-Asparaginase production in rotating bed reactor from Rhizopus microsporus IBBL-2 using immobilized Ca-alginate beads

“The present work reports on the production of extracellular L-asparaginase from Rhizopus microsporus IBBL-2 using submerged fermentation (SmF) process free of glutaminase and urease activities. Primary studies done in shake flask showed that the highest L-asparaginase activity of 12.68 U/mL was produced at 72 h with optimized fermentation parameters such as pH 6.0, 4×10^6 fungal cells/mL, and agitation of 180 rpm at 30 °C using one-factor-at-a-time (OFAT). Different substrates, nitrogen sources, temperature, pH, the initial number of cells and metal ions were tested to determine the impact on enzyme production. L-Asparaginase activity of 17.68 U/mL was produced after 48 h using immobilized calcium-alginate (Ca-alginate) cells. 4×10^6 cells/mL was entrapped in 3% (W/V) of alginate bead of size 2 mm each at a temperature of 30 °C and pH of 6. The process was optimized using L9 (3^4) Taguchi Orthogonal Array (OA) technique with a regression coefficient (R 2) value of 0.9709, F value of 33.34 and p value of 0.0025. Scale-up studies involving 200-mL and 1-L rotating bed reactor (RBR) using immobilized beads were done and the results obtained are 20.21 U/mL and 19.13 U/mL, respectively, the increased activity with immobilization accounts for reduced shear on cells due to increased stability as compared to the free-flowing cells.”

Highlights:

• The present work reports on the production of extracellular L-asparaginase from Rhizopus microsporus IBBL-2 using submerged fermentation (SmF) process free of glutaminase and urease activities.
• “A scale-up study using the 200-mL and 1-L RBR is also done to show the effectivity of the process.”
• “The scale-up studies conducted have shown that the results are replicates of the flask-scale with activities of 20.21 U/mL in 200-mL RBR and 19.13 U/mL in 1-L RBR, and there is no loss in the efficiency during the scale-up process.”