Sequential fed‐batch fermentation as strategy for the production of drought stress tolerance‐promoting compounds
Aiden Escalante, Tatiana Solis, Christian Quijia, Mariela Perez‐Cárdenas, Katherine Triviño‐Cepeda, Andrea C. Zurita‐Leal, Ellana Boada, Javiera Toledo‐Alarcón, Oscar Franchi, Alberto AguirreAbstract
BACKGROUND
Climate change represents a critical challenge for global agriculture. Recurrent drought events associated with climate variability induce drought stress in crops, ultimately compromising productivity. Therefore, the development of effective drought adaptation strategies in agricultural systems is essential. In this context, this study evaluated a strategy for the fermentative production of bioactive compounds that enhance drought stress tolerance in lentil plants, based on two sequential fed‐batch culture stages: an initial fed‐batch containing endophytic fungi, followed by a second fed‐batch containing rhizosphere bacteria.
RESULTS
A quadratic response surface model was successfully developed and optimized, demonstrating that a low dose combined with a high application frequency of the second fed‐batch culture broth without cells maximizes stem growth efficiency. Under optimized conditions, drought‐stressed lentil plants treated with the microbial broth without cells exhibited a stem growth efficiency of 48% and 92% of leaves with normal morphology, compared to untreated drought‐stressed controls (7% stem growth efficiency and 37% normal leaf morphology). These findings confirm the efficacy of the produced microbial broth as a biostimulant for enhancing drought stress tolerance. The dominant bacterial genera identified in the second fed‐batch were Pseudomonas (52.43%), Flavobacterium (40.67%), and Sphingobium (5.29%). On the other hand, the dominant fungal genus in fed‐batch stage 1 was Talaromyces (93.6%). The positive effect on drought stress tolerance promotion observed in this study is likely associated with metabolites produced by both fungi (spiculisporic acid, citric acid, FA 9:0 + 10, FA 9:1 + 10, sebacic acid and chrysoeriol) and bacteria (ricinoleic acid, 10‐hydroxydecanoic acid, 2,5‐dihydroxybenzoic acid, 4‐decyl‐3‐hydroxy‐5‐oxooxolane‐2,3‐dicarboxylic acid, chrysoeriol, ω‐hydroxydodecanoic acid, p ‐coumaric acid, and thymol‐β‐
CONCLUSION
The sequential fed‐batch system employed in this study (fed‐batch stage 1: endophytic fungi; fed‐batch stage 2: rhizosphere bacteria) proved to be effective in generating compounds associated with enhanced drought stress tolerance in lentil plants. © 2026 Society of Chemical Industry (SCI).