The process mentioned in the title has been developed by Marianne Pusztai-Carey and her co-biochemists all of Ontario, and according to their process, daughter toxins are first generated by subjecting a protoxin-containing material, such as parasporal crystals of Bacillus thuringiensis, to limited proteolytic enzyme in an aqueous suspension having a pH above 9.5. The daughter toxins are then separated by high performance anion-exchange liquid chromatography at a constant pH in excess of 10 in an increasing gradient of a salt, preferably sodium chloride. The gradient conditions, which are specific for the column used, are achieved by employing a series of buffers having increasing concentration of the salt and introduced at a predetermined time and rate. The procedure provides a chromatogram showing clearly indentifiable peaks of toxins and permits therefore the qualitative and quantitative characterization of the original mixture and isolation of the individual toxins. By this it provides a means of screening and testing new Bacillus thuringiensis isolates. The digestion and isolation conditions permit the production of the toxins in a biologically fully active state. Purified parasporal crystals were prepared following literature procedures (see e.g. [1]). For the tryptic digestion 20 mg/ml NRD-12 crystal suspension in 0.1 m CAPS/NaOH, pH 10.5 buffer was treated with 1 mg/ml commercial pancreatic trypsin. The reaction mixture was stirred at room temperature overnight and centrifuged at 10 000 rpm for 15 min. The decanted supernatant was filtered through a 0.22 μm cut-off membrane. The HPLC separation using a weak anion-exchanger was carried out using Waters 990 solvent delivery system equipped with an automatic injector and a photodiode array detector. Protein PAK DEAE 5PW anion exchange column (7.5 @ 75 mm analytical or 21.5 @ 150 mm semipreparative, Waters) was used: injection volume-1-20 000 μl; flow rate -- 4 ml/min. Complex elution gradients employed three buffers: @ The employed gradient conditions are shown in Fig. 1. Figure 2 shows a chromatogram of the tryptic digest under these gradient conditions, where the peaks of separated toxins are marked as B, C and D.