Screening and optimizing fermentation production of l-asparaginase by Aspergillus terreus strain S-18 isolated from the Brazilian Caatinga Biome.

AIMS: The aim of this study was to find new eukaryotic sources of the l-asparaginase (l-ASNase), since the prokaryotic sources of the enzyme are well-reported as causing allergic hypersensitivity reactions in a significant number of patients. This report describes screening for l-ASNase production by filamentous fungi isolated from the Brazilian Caatinga, and the optimization of fermentation parameters to increase fungal growth and improve yield in the production of l-ASNase. METHODS AND RESULTS: Thirty-two filamentous fungi were investigated in this study. When Aspergillus terreus strain S-18 was cultured in a proline-enriched medium, intracellular l-ASNase was expressed in concurrence with reduced l-glutaminase (l-GLUase) and protease activities. Fermentation conditions were then optimized in a 5-l bioreactor system to produce a maximum volumetric yield of 108 U total of l-ASNase activity. CONCLUSIONS: The work reported here represents the first attempt to produce l-ASNase by filamentous fungi isolated from Brazil and offers a promising alternative eukaryotic source for l-ASNase production. SIGNIFICANCE AND IMPACT OF THE STUDY: In order to minimize the side effects caused by bacterial l-ASNase, the search of eukaryotic micro-organism for l-ASNase was carried out in fungi. This study demonstrates the diversity of filamentous fungi isolated from the Brazilian Caatinga Biome and the importance of knowledge of the microbial metabolism to obtain high concentrations of biotechnological products.

L-asparaginase isolated from Streptomyces ansochromogenes promotes Th1 profile and activates CD8+ T cells in human PBMC: an in vitro investigation.

AIMS: A new L-asparaginase produced by Streptomyces ansochromogenes UFPEDA 3420 actinobacteria was used in this study against human lymphocyte cultures to evaluate the immunological profile induced by this enzyme. METHODS AND RESULTS: Cultures of lymphocytes were stimulated with S. ansochromogenes L-asparaginase, and cytotoxicity, cell viability, cell stimulation and cytokine production were analysed. This new S. ansochromogenes L-asparaginase induced activation and proliferation of the TCD8+ lymphocyte subset and produced higher TNF-α, IFN-γ, IL-2 and IL-10 levels in a 24-h assay. CONCLUSION: Streptomyces ansochromogenes L-asparaginase is a promising molecule to be used in in vivo models and to deepen preclinical tests against acute lymphoblast leukaemia. SIGNIFICANCE AND IMPACT OF STUDY: L-asparaginase is an indispensable component of the chemotherapeutic treatment of acute lymphoblast leukaemia (ALL) and acute myeloid leukaemia (AML). Currently, drugs such as Asparaginase® , Kidrolase® , and Elspar® and Erwinase® are efficient against leukemic disease, but promote immunosuppression and other side effects in human organisms. Our purified S. ansochromogenes L-asparaginase showed promissory results inducing, in vitro, higher immunostimulation in human PBMC, especially in T CD8+ lymphocyte subsets.

Molecular identification and physiological characterization of Zymomonas mobilis strains from fuel-ethanol production plants in north-east Brazil.

Zymomonas mobilis has long attracted attention owing to its capacity to ferment hexose to ethanol. From a taxonomic viewpoint, Z. mobilis is a unique species of the genus Zymomonas, separated into three subspecies, Z. mobilis subsp. mobilis, Z. mobilis subsp. pomaceae and Z. mobilis subsp. francensis on the basis of physiological tests, which are often unreliable owing to the genetic proximity among these species. Currently, the use of molecular techniques is more appropriate for identification of these bacterial subspecies. In this study, the 32 strains of Z. mobilis present in the UFPEDA bacterial collection were characterized using molecular techniques, such as sequencing of the 16S rDNA gene and its theoretical restriction profile, classifying them as members of the subspecies, Z. mobilis subsp. mobilis. In addition, anaerobic cultivations were performed, which showed the biological diversity of the strains in terms of growth, sugar consumption and ethanol production. From these results, it was possible to identify the strain Z-2-80 as a promising bacterium for use in the fermentation process. SIGNIFICANCE AND IMPACT OF THE STUDY: Zymomonas mobilis is a bacterium of great relevance to biotechnology, owing to its capacity to ferment hexose to ethanol. On a molecular basis, 32 isolates were identified as Z. mobilis subsp. mobilis. However, intraspecific diversity was identified when these were grown under strictly anaerobic conditions. The results obtained from this study suggest a strain of Z. mobilis as an alternative for use in the fermentation process.