期刊
3 BIOTECH
卷 9, 期 7, 页码 -出版社
SPRINGER HEIDELBERG
DOI: 10.1007/s13205-019-1814-5
关键词
Aspergillus oryzae; Aspergillus niger; Characterization; L-Asparaginase
资金
- Sao Paulo Research Foundation-FAPESP [2012/24046-7]
- National Counsel of Technological and Scientific Development-CNPq
This study describes the production of native l-asparaginases by submerged fermentation from Aspergillus strains and provides the biochemical characterization, kinetic and thermodynamic parameters of the three ones that stood out for high l-asparaginase production. For comparison, the commercial fungal l-asparaginase was also studied. Both commercial and l-asparaginase from Aspergillus oryzae CCT 3940 showed optimum activity and stability in the pH range from 5 to 8 and the asparaginase from Aspergillus niger LBA 02 was stable in a more alkaline pH range. About the kinetic parameters, the denaturation constant increased with the heating temperature for all l-asparaginases, indicating that the l-asparaginase activity decreased at higher temperatures, especially above 60 degrees C. Moreover, l-asparaginase from A. oryzae CCT 3940 remained stable after 60min at 50 degrees C. None of the l-asparaginases were inhibited by high NaCl concentrations, which are highly desirable for food industry application. The catalytic activities of all the l-asparaginases were enhanced by the presence of Mn2+ and inhibited by p-chloromercuribenzoate and iodoacetamide. The l-asparaginase from the Aspergillus strains and the commercial enzyme had similar K-m when l-asparagine was used as substrate. None of the l-asparaginases, except the l-asparaginase from A. niger LBA 02, could hydrolyze the substrate l-glutamine, which is of interest for medical proposes, since the glutaminase activity is usually related to adverse reaction during the leukemia treatment. This study showed that these new three non-recombinant l-asparaginases studied have potential application in the food and pharmaceutical industries, especially due to their good thermostability.
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