EVALUATION OF THE MEDICAL ENZYME PRODUCTION POTENTIALS OF ASPERGILLUS SECTION NIGRI SPECIES ISOLATED FROM DRY FIGS IN TURKEY

Project no. 22270 · Status: Kapanmış (Yayın bekleniyor) · 2021

Summary

Aspergillus section Nigri group includes many species of biotechnological importance and interest. The species in this group have the potential to produce important medical enzymes for the treatment of many diseases (e.g. lactose intolerance, celiac disease, acute lymphoblastic leukemia). The advantages of this group compared to bacterially produced enzymes (the reduction of immunogenic toxicity with the use of eukaryotic microorganisms), it is thought to contribute to the elimination of important medical deficiencies. In addition, the fact that enzymes obtained from Aspergillus species have an extracellular character compared to other microorganisms, have high thermal tolerance and show activity at low pH is important in terms of being more applicable in the industry.The aim of this study was to determine the β-galactosidase and prolyl endopeptidase production potential of non-mycotoxin producing and molecularly identified Aspergillus spp. isolated from dried figs. Within this scope, 48 fungi were screened by rapid plate screening method for β-galactosidase and Prolyl endopeptidase. After determining the producer(s) of both enzymes (A. welwitschiae 1308 for prolyl endopeptidase and A. brasiliensis 1137 for β-galactosidase), liquid cultures were produced and the fermentation liquids were concentrated by ultrafiltration. While no prolyl endopeptidase enzyme activity was found in the concentrated sample, partial characterization studies of this enzyme were carried out since β-galactosidase enzyme activity was detected.As a result of partial characterization studies, the optimum temperature of β-galactosidase enzyme was determined as 60 °C and the optimum pH as 4.5. It was determined that the thermal stability of the enzyme was quite stable in the range of 4-30 °C, it lost 43% of its activity at 70 °C and 91% at 80 °C and gradually lost its activity as the temperature increased. While the pH stability of β-galactosidase was well maintained in the pH range of 4,0-6.0, 50% decrease in activity was detected at values above these pH values. Km and Vmax for β-galactosidase enzyme were determined as 2.780± 0,4503mM and 0,04001±0,0018 µmoL/min, respectively. FeCl3 increased the enzyme activity by 4% in relative terms, respectively. On the other hand, CuSO4, ZnSO4 and CaCl2 caused 25%, 40% and 21% inhibition of enzyme activity, respectively. The high stability of the enzyme against acidic pHs and high temperatures is important for the use of β-galactosidase enzyme in different biotechnological applications.

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