Optimization of triterpenoids biosynthesis in Athelia termitophila as a source of natural products

Triterpenoids exhibit considerable potential and are extensively utilized in both food and pharmaceutical industries. However, Athelia termitophila (TMB) naturally harbors only trace amounts of these compounds. Consequently, this study sought to optimize the composition of the culture medium and its cultivation parameters to augment both triterpenoids biosynthesis and TMB biomass. To this end, a series of systematic experiments were carried out. At the outset, a One Factor at a Time (OFAT) approach was employed to identify key culture components and conditions. Based on the OFAT findings, six factors were selected for further investigation using the Plackett-Burman design (PBD) to assess their influence on triterpenoids production and biomass yield. The PBD outcomes pinpointed three critical factors-cultural duration, yeast extract powder, and KH₂PO₄-each of which was subjected to further optimization through the Box-Behnken design (BBD). The BBD analysis determined the optimal culture medium and conditions: 30 g/L corn starch, 13.44 g/L yeast extract powder, 4.74 g/L KH₂PO₄, a liquid-to-volume ratio of 130/250 mL, 6% inoculum volumes, and a cultivation period of 7.8 days. Upon optimization, both triterpenoids yield (1.9-fold increase) and mycelial biomass (1.66-fold increase) were significantly enhanced compared to the unoptimized medium. This study not only provides a robust methodology for enhancing triterpenoids content and mycelial biomass in TMB, but also contributes novel insights into the biosynthesis of triterpenoids.