Fermentative production of extracellular amylase from novel amylase producer, Tuber maculatum mycelium, and its characterization

Abstract

Truffles are symbiotic hypogeous edible fungi (form of mushroom) that form filamentous mycelia in their initial phase of the growth cycle as well as a symbiotic association with host plant roots. In the present study, Tuber maculatum mycelia were isolated and tested for extracellular amylase production at different pH on solid agar medium. Furthermore, the mycelium was subjected to submerged fermentation for amylase production under different culture conditions such as variable carbon sources and their concentrations, initial medium pH, and incubation time. The optimized conditions after the experiments included soluble starch (0.5% w/v), initial medium pH of 7.0, and incubation time of 7 days, at room temperature (22 ± 2 °C) under static conditions which resulted in 1.41 U/mL of amylase. The amylase thus obtained was further characterized for its biocatalytic properties and found to have an optimum activity at pH 5.0 and a temperature of 50 °C. The enzyme showed good thermostability at 50 °C by retaining 98% of the maximal activity after 100 min of incubation. The amylase activity was marginally enhanced in presence of Cu²⁺ and Na⁺ and slightly reduced by K⁺, Ca²⁺, Fe²⁺, Mg²⁺, Co²⁺, Zn²⁺, and Mn²⁺ ions at 1 mM concentration.

Keywords:

• Amylase
• biochemical characterization
• starch
• truffle
• Tuber maculatum

Ethical Approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Acknowledgments

Authors are grateful to Mr. Antti Kinnunen for administrative service and Mrs. Heli Valtonen for technical assistance.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was conducted at Juva Truffle Center Finland. The financial support of Regional Council of Southern Savo, Finland, is appreciated and thanked.