Large-scale production and purification of Ascochyta caulina phytotoxins and a new HPLC method for their analysis

The toxins produced by Ascochyta caulina have potential as a natural herbicide. They are three basic non-protein amino acids. Considering the need to optimize and maximize their production by fermentation in order to obtain large amounts of toxins, a new, simple, and inexpensive HPLC method was developed. This new process allows rapid evaluation of the toxin content in the fungal culture filtrates. The simplification and scaling up of the entire process include a single-step purification of the filtrates by cationic exchange chromatography by using a reusable resin with a high exchange capacity and distilled water and dilute ammonia as eluents. This process allows the fast and easy purification of large volumes of filtrates and the harvest of large amounts of a mixture containing the three pure toxins. These methods are described here and their potential to be scaled up to a pre-industrial level is discussed.