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Enhanced triterpene acid production by Ganoderma lucidum using a feeding stimulus integrated with a two‐stage pH‐control strategy

Wang, Xiao‐Ling, Yang, Hailong, Liu, Gao‐Qiang
Journal of chemical technology and biotechnology 2016 v.91 no.12 pp. 2974-2982
Catharsius molossus, Ganoderma lucidum, fermentation, fermenters, medicinal insects, pH, triterpene acids
BACKGROUND: Triterpenes (especially triterpene acids) are some of the major physiologically active components of Ganoderma lucidum. However, submerged fermentation techniques for triterpenes have not been optimized for commercial use, and the total triterpene yield is still very low. The aim of this work was to develop a two‐stage pH‐control strategy integrated with the use of an ether extract from the medicinal insect, Catharsius molossus (EECM), as a stimulus for enhanced G. lucidum triterpene acid production. RESULTS: Triterpene acid production of 302.76 mg L⁻¹ was obtained in G. lucidum cultured with the EECM; this production was higher by 60% than that of the control cultures not fed the EECM. Based on the EECM feeding method, a new two‐stage pH‐control strategy was integrated, resulting in triterpene acid yields of 361.47 mg L⁻¹. Subsequent studies optimized the interaction between EECM feeding and two‐stage pH‐control strategies, which resulted in an optimal EECM concentration of 185.89 mg L⁻¹ and optimal pH values of 5.07 in the first 72 h incubation and 4.37 after 72 h, with a maximum triterpene acid concentration of 449.37 mg L⁻¹. This represented a 137% increase compared with that of the control cultures. Furthermore, when a 150 L fermenter was used under these conditions, a triterpene acid concentration of 431.83 mg L⁻¹ was achieved. CONCLUSIONS: The enhanced production of triterpene acid in submerged cultures of G. lucidum was achieved using an EECM feeding stimulus integrated with a two‐stage pH‐control strategy at large scale. © 2016 Society of Chemical Industry