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

ABSTRACT: 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-1 was produced at 72 h with optimized fermentation parameters such as pH 6.0, 4 × 106 fungal cells mL-1, 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-1 was produced after 48 h using immobilized calcium-alginate (Ca-alginate) cells. 4 × 106 cells mL-1 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 (34) 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-1 and 19.13 U mL-1, respectively, the increased activity with immobilization accounts for reduced shear on cells due to increased stability as compared to the free-flowing cells.

SUBMITTER: Ashok A

PROVIDER: S-EPMC6717606 | biostudies-literature | 2019 Sep

REPOSITORIES: biostudies-literature

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

Ashok Anup A Devarai Santhosh Kumar SK

3 Biotech 20190831 9

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-1 was produced at 72 h with optimized fermentation parameters such as pH 6.0, 4 × 106 fungal cells mL-1, and agitation of 180 rpm at 30 °C using one-factor-at-a-time (O ...[more]

PMID: 31497467

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Project description:Sinopulmonary and rhinocerebral zygomycosis has been increasingly found in patients with hematological malignancies and bone marrow transplantation, but intestinal zygomycosis remains very rare in the literature. We investigated an outbreak of intestinal infection due to Rhizopus microsporus in 12 patients on treatment for hematological malignancies over a period of 6 months in a teaching hospital. The intake of allopurinol during hospitalization (P < 0.001) and that of commercially packaged ready-to-eat food items in the preceding 2 weeks (P < 0.001) were found to be independently significant risk factors for the development of intestinal zygomycosis. A total of 709 specimens, including 378 environmental and air samples, 181 food samples, and 150 drug samples, were taken for fungal culture. Among them, 16 samples of allopurinol tablets, 3 prepackaged ready-to-eat food items, and 1 pair of wooden chopsticks were positive for Rhizopus microsporus, which was confirmed by ITS1-5.8S-ITS2 rRNA gene cluster (internal transcribed spacer [ITS]) sequencing. The mean viable fungal counts of allopurinol obtained from wards and pharmacy were 4.22 x 10(3) CFU/g of tablet (range, 3.07 x 10(3) to 5.48 x 10(3)) and 3.24 x 10(3) CFU/g of tablet (range, 2.68 x 10(3) to 3.72 x 10(3)), respectively, which were much higher than the mean count of 2 x 10(2) CFU/g of food. Phylogenetic analysis by ITS sequencing showed multiple clones from isolates of contaminated allopurinol tablets and ready-to-eat food, of which some were identical to patients' isolates, and with one isolate in the cornstarch used as an excipient for manufacture of this drug. We attempted to type the isolates by random amplification of polymorphic DNA analysis, with limited evidence of clonal distribution. The primary source of the contaminating fungus was likely to be the cornstarch used in the manufacturing of allopurinol tablets or ready-to-eat food. Rhizopus microsporus is thermotolerant and can multiply even at 50 degrees C. The long holding time of the intermediates during the manufacturing process of allopurinol amplified the fungal load. Microbiological monitoring of drugs manufactured for highly immunosuppressed patients should be considered.

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

Publications

l-Asparaginase production in rotating bed reactor from <i>Rhizopus microsporus</i> IBBL-2 using immobilized Ca-alginate beads.

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