Nutritional factors effecting the production of L-asparaginase by the Fusarium sp.
The present work was directed to develop evaluation of nutritional requirements (carbon and nitrogen source) for the production of L-asparaginase by isolated Fusarium sp. The study was aimed at ascertaining optimal nutritional conditions for maximal enzyme production by submerged fermentation process. Fusarium moniliforme, Fusarium oxysporum and Fusarium semitectum were isolated from the soil samples of Warangal. Fusarium sp. used in the present investigation exhibited significant variations in their preference to carbon and nitrogen sources for their growth and L-asparaginase production. The highest amount of enzyme production by F. semitectum (328 IU/ml), F. moniliforme (300 IU/ml) and F. oxysporum (210 IU/ml) was obtained with glucose as carbon source, with lactose presenting the second best carbon source for F. semitectum (218 IU/ml) and F. oxysporum (178 IU/ml) and mannose for F. moniliforme (213 IU/ml). Fusarium sp. has shown great specificity for nitrogen source present in the medium while they failed to grow in the absence of nitrogen source. F. moniliforme (376 IU/ml) and F. semitectum (404 IU/ml) exhibited maximum growth and L-asparaginase production on proline. It can be seen that the enzyme production by F. oxysporium was higher in sodium nitrate as nitrogen source (360 IU/ml). Lysine was responsible for least production of L-asparaginase in all the three Fuasrium sp. The highest amount of biomass was obtained with proline as nitrogen source. With few exceptions, a positive correlation could be observed between growth and L-asparaginase production.
Key words: Fusarium, L-asparaginase, nutritional factors, submerged fermentation.