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Introduction
L-Asparagine is hydrolyzed by L-asparaginase (L-asparagine amido hydrolase E.C.3.5.1.1) to form aspartic acid and ammonia. L-Asparaginase is present in animals, plants and microbes but not in humans. Fungal L-asparaginases are enzymes of great therapeutic significance due to their use in anti-leukemic and antilymphoma treatment.1,2 L-Asparaginase has a growing demand in medical application and food industries.3 L-asparaginase production from microbes has more attention because the process is cost-effective and environmental friendly.4 Bacteria such as Escherichia coli and Erwinia carotova are the best producers of L-asparaginase and are used in pharmaceutical industries. There are only few researches carried out on L-asparaginase production by endophytic fungi.5,6,7 Recently, L-asparaginase obtained from fungi, such as Fusarium, Aspergillus and Penicillium, show additional promise since their L-asparaginases have less adverse effects when compared to bacterial L-asparaginases.8 Various types of cancers including melanosarcoma, reticulosarbom, acute myelocytic leukemia, lymphosarcoma, Hodgkin disease, chronic lymphocytic leukemia, acute myelomonocytic leukemia and acute lymphoblastic leukemia specially in children can be treated using L-asparaginase.9,10 L-Asparaginases are effective because neoplastic cells cannot synthesize L-asparagine and therefore rely on L-asparagine found within blood plasma. Research has demonstrated that plasma L-asparagine levels in the blood can be reduced through intravenous injections of L-asparaginases.11 Submerged fermentation (SmF) is a very effective technique and require low energy and less risk of contamination.12 Screening and estimation of the environmental factors and nutritional parameters are more essential stages of bioprocess.13 Minimum information is available related to the optimization of medium conditions using statistical methods for enzyme production. Response surface methodology (RSM) uses mathematical equations to predict the relationship between response and variables.14,15 The present study was carried out to formulate a suitable medium and to optimize various nutritional factors specifically carbon, nitrogen, natural inducers and culture conditions for maximizing the L-asparaginase production by Fusarium sp. LCJ273 under submerged fermentation. Optimization by RSM was used to observe the correlation between the L-asparaginase production and significant parameters.
Material and Methods
Microorganism and Growth Medium
The fungal strain Fusarium sp. LCJ273 was isolated from Adhatoda vasica collected from Chennai. It was grown in Potato Dextrose Agar (PDA) medium containing Potato (200 g/L), Dextrose (20 g/L) and agar (15g/L). The fungal strain were periodically sub-cultured once in...