Optimization of the fermentation media, mathematical modeling, and enhancement of paclitaxel production by Alternaria alternata after elicitation with pectin

Alternaria alternata fungus is a potent paclitaxel producer isolated from Corylus avellana. The

major challenge is the lack of optimized media for endophytic fungi productivity. In the effort to

maximize the production of taxoids by A. alternata, several fermentation conditions, including pH

(pH 4.0–7.0), different types and concentrations of carbon (fructose, glucose, sucrose, mannitol,

sorbitol, and malt extract), and nitrogen (urea, ammonium nitrate, potassium nitrate, ammonium

phosphate, and ammonium sulfate) were applied step by step. Based on the results, A. alternata in a

medium containing sucrose 5% (w/v) and ammonium phosphate 2.5 mM at pH 6.0 showed a rapid and

sustainable growth rate, the highest paclitaxel yield (94.8 μg gFW−1 vs 2.8 μg gFW− 1 in controls), and

the maximum content of amino acids. Additionally, the effect of pectin was evaluated on fungus, and

mycelia harvested. Pectin significantly enhanced the growth and taxoid yield on day 21 (respectively

171% and 116% of their corresponding on day 7). The results were checked out by mathematical

modeling as well. Accordingly, these findings suggest a low-cost, eco-friendly, and easy-to-produce

approach with excellent biotechnological potential for the industrial manufacture of taxoids.