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

Abstract

<p><em>Alternaria alternata</em> fungus is a potent paclitaxel producer isolated from <em>Corylus avellana</em>. The</p><p>major challenge is the lack of optimized media for endophytic fungi productivity. In the effort to</p><p>maximize the production of taxoids by <em>A. alternata</em>, several fermentation conditions, including pH</p><p>(pH 4.0–7.0), different types and concentrations of carbon (fructose, glucose, sucrose, mannitol,</p><p>sorbitol, and malt extract), and nitrogen (urea, ammonium nitrate, potassium nitrate, ammonium</p><p>phosphate, and ammonium sulfate) were applied step by step. Based on the results, A. alternata in a</p><p>medium containing sucrose 5% (w/v) and ammonium phosphate 2.5 mM at pH 6.0 showed a rapid and</p><p>sustainable growth rate, the highest paclitaxel yield (94.8 μg gFW−1 vs 2.8 μg gFW− 1 in controls), and</p><p>the maximum content of amino acids. Additionally, the effect of pectin was evaluated on fungus, and</p><p>mycelia harvested. Pectin significantly enhanced the growth and taxoid yield on day 21 (respectively</p><p>171% and 116% of their corresponding on day 7). The results were checked out by mathematical</p><p>modeling as well. Accordingly, these findings suggest a low-cost, eco-friendly, and easy-to-produce</p><p>approach with excellent biotechnological potential for the industrial manufacture of taxoids.</p>