Potential use of orange peel substrate to produce intracellular L-asparaginase by the endophyte Diaporthe sp. URM 8378

Ana Patrícia Sousa Lopes de Pádua, Leticia Francisca da Silva, Gualberto Segundo Agamez-Montalvo, Jadson Diogo Pereira Bezerra, Adalberto Pessoa Júnior, Cristina Maria de Souza-Motta & Keila Aparecida Moreira

Sydowia 76: 161-177

Published online on July 16th, 2024

This study aimed to select an agro-industrial substrate with low cost and efficiency for the production of L-asparaginase (LASNase) by the endophyte Diaporthe sp. URM 8378 using submerged fermentation and optimized enzymatic production. Fungal growth and L-asparaginase production curves were generated. A factorial experimental design (23) was carried out, and enzyme production was analysed using pH, substrate (%), and inoculum concentration (g) as variables. Orange peel flour was found to be the best inducer, and Diaporthe sp. URM 8378 produced a maximum intracellular yield for L-asparaginase of 2.56 U/g, followed by 0.85 U/g using eggshell flour, 0.80 U/g with L-asparagine (control) and 0.74 U/g with L-proline. The highest biomass production by the fungus (0.72 g/ml) occurred after 144 hours of cultivation at pH 2.5, and the best L-asparaginase production (1.05 U/g) occurred after 48 hours of fermentation at pH 4.8. The production of L-asparaginase was partially optimized between 2.56 U/g to 3.46 U/g at pH 6.0, inoculum of 1.5 g and orange peel flour concentration of 1.5 %, an increase of 26.02 % in relation to the initial production. The orange peel flour proved to be effective in increasing the L-asparaginase production of the endophyte Diaporthe sp. URM 8378.

Keywords: Agro-industrial waste, anticancer enzyme, Diaporthe sp., highest enzyme productivity, submerged fermentation.

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