Optimisation of carbon sources and pH for mycelial growth of a wild Ganoderma lucidum YD09.1 strain from Yok Don national park, Vietnam

Abstract

The demand for Lingzhi mushrooms (Ganoderma lucidum) has been increasing; therefore, the optimisation of propagation and cultivation protocols for this species plays a key role in enhancing overall biomass productivity and increasing the concentration of vital bioactive compounds. Within the framework of this research, the G. lucidum strain YD09.1, originally isolated from Yok Don national park (Vietnam), underwent rigorous identification via morphological analysis integrated with sequencing of the internal transcribed spacer (ITS) rDNA region. The macromorphological features of the fruiting bodies, alongside their complex microscopic structural characteristics, definitively confirmed the specimen’s taxonomic identity as G. lucidum. Furthermore, data derived from ITS region sequencing and subsequent BLAST analysis demonstrated that the genetic sequence of this strain shared a similarity level exceeding 98% with established reference sequences, thereby validating the classification of YD09.1 within the G. lucidum species. Of four distinct carbon sources tested (glucose, maltose, lactose, and sucrose), glucose at a concentration of 25 g/l was identified as the most optimal carbon source for mycelial expansion, achieving a radial growth rate of 18.3 mm/day. Furthermore, maltose and sucrose at 30 g/l yielded comparable growth performance, while lactose resulted in significantly inferior development. Additionally, the optimal pH level for the mycelial growth of G. lucidum YD09.1 strain was determined to be approximately 6.0.