Comparative study of two purified inulinases from thermophile Thielavia Terrestris NRRL 8126 and mesophile Aspergillus Foetidus NRRL 337 grown on Cichorium Intybus l

Abstract

Thirty fungal species grown on Cichorium intybus L. root extract as a sole carbon source, were screened for the production of exo-inulinase activities. The thermophile Thielavia terrestris NRRL 8126 and mesophile Aspergillus foetidus NRRL 337 gave the highest production levels of inulinases I & II at 50 and 24 ºC respectively. Yeast extract and peptone were the best nitrogen sources for highest production of inulinases I & II at five and seven days of incubation respectively. The two inulinases I & II were purified to homogeneity by gel-filtration and ion-exchange chromatography with 66.0 and 42.0 fold of purification respectively. The optimum temperatures of purified inulinases I & II were 75 and 50 ºC respectively. Inulinase I was more thermostable than the other one. The optimum pH for activity was found to be 4.5 and 5.5 for inulinases I & II respectively. A comparatively lower Michaelis-Menten constant (2.15 mg/ml) and higher maximum initial velocity (115 µmol/min/mg of protein) for inulinase I on inulin demonstrated the exoinulinase's greater affinity for inulin substrate. These findings are significant for its potential industrial application. The molecular mass of the inulinases I & II were estimated to be 72 & 78 kDa respectively by sodium dodecyl sulfate-polyacrylamide gel electrophoresis

Production, Purification and Characterization of Inulinase from a Newly Isolated <i>Streptomyces</i> sp. CP01

“…Effect of nitrogen source on the enzyme production was performed by cultivating CP01 in the basal medium containing 1% inulin extract and 0.3% (w/v) of different nitrogen sources. Similar to Thielaria terrestris NRRL 8126 and Aspergillus foetidus NRRL 337 reported by Fawzi [26], tryptone was found to be the best nitrogen source for inulinase production and the optimal concentration for CP01 was obtained at 0.7% (W/V) yielding inulinase activity of about 1.3 U/ml (Figure 2). Inulinase from Streptomyces sp.…”

Rapid and efficient bioconversion of chicory inulin to fructose by immobilized thermostable inulinase from Aspergillus tubingensis CR16

“…It was also evident from the result that in the temperature range examined, relative activity of immobilized inulinase was quite high compared to free inulinase which showed that immobilization positively affected the temperature tolerance of inulinase during the reaction. Higher temperature optima for enzyme reaction is critical for industries as it prevents microbial contamination of the final product, lowers viscosity, as well as it allows the use of higher concentrations of inulin due to increased solubility [7]. There are studies performed by Gill et al [9] and Yun et al [29] which are in accordance with the present findings.…”

Yacon Flour and Corn Steep Liquor as Substrate for Inulinase and Biomass Production by Kluyveromyces Marxianus NRRL Y-7571

“…In this case, yacon flour and corn steep liquor presented good results, because the best biomass and inulinase productions were obtained at relatively low concentrations of these carbon and nitrogen sources, 7.0% and 2.7%, respectively. This is a common characteristic in studies reporting microbial inulinase production and most describe the best production at low concentrations of the carbon source: 4% chicory root extract [42], 3% Jerusalem artichoke [37], 2.5% to 6.5% buckwheat [43]. This occurs because inulinase is an enzyme that presents catabolic repression in the presence of excess substrate, especially the carbon source [44].…”