Optimization of inulinase production using Jerusalem artichoke (Helianthus tuberosus) as cheap substrate and comparison with pure chicory inulin

Abstract

Jerusalem artichoke (JA) is a nutritional vegetable for human diet depending on its natural structure, especially high inulin content and it is the second inulin source for commercial production in the world, after chicory. It was aimed to investigate the inulinase production capability of Galactomyces geotrichum TS61 (GenBank accession: MN749818) using JA as an economical and effective substrate comparing with the pure chicory inulin and to optimize the fermentation using Taguchi design of experiment (DOE) in this study. Besides, the effects of sucrose on inulinase production either combined with JA or in its absence were also studied. Taguchi L16 orthogonal array was employed for optimization. Both of inulinase activities obtained from JA and pure inulin gave the maximum result at the 10th experimental run as 40.21 U/mL and 57.35 U/mL, respectively. The optimum levels were detected for each factor as, 30 g/L JA, 30 g/L sucrose, pH 5.5, and four days for time. The predicted value was found as 41.63 U/mL that was similar to the obtained result as 41.17 U/mL. Finally, inulinase activity was increased approximately 8-folds after optimization. The sucrose-free medium had similar effects with higher concentrations of JA at long incubation time. This is the first investigation about inulinase production by G. geotrichum.

NOVELTY IMPACT STATEMENT

• Low-cost inulinase production was achieved using an economical substrate

• Sucrose effects were investigated in detail on inulinase production

• Use of Taguchi DOE supported effective enzyme production

Keywords:

• Enzyme
• Jerusalem artichoke
• Galactomyces geotrichum
• sucrose

Acknowledgements

The authors thank to all the staff of YUTAM.

Ethical approval

This study does not include any studies with human participants or animals.

Author contributions

OCT: Methodology, data analysis, software, investigation, conceptualization, writing, editing and supervision. GET: Data analysis, software, editing.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data can be available from the corresponding author upon reasonable request.

Additional information

Funding

No funding was used for this work.