Application of modified β-glucan/montmorillonite- based sodium alginate microsphere adsorbents for removing deoxynivalenol and zearalenone from corn steep liquor

Removing mycotoxins from by-products of corn wet-milling processing presents a critical challenge facing the grain industry. Corn steep liquor (CSL) is rich in protein and other nutrients. However, CSL is usually contaminated by mycotoxins, including deoxynivalenol (DON) and zearalenone (ZEN), which can be removed using suitable adsorbents. In this study, the efficiency of modified sodium alginate (SA)/β-glucan/montmorillonite (Mt) (SA/β-glucan/Mt) microsphere adsorbents in moving DON and ZEN from CSL was investigated. For this, the modified SA/β-glucan/Mt microspheres were analyzed using a scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR). The adsorption of microspheres was characterized by physical adsorption and hydrogen bonding analyses. The optimal adsorption conditions (i.e., incubation time, temperature, and dose) of the microspheres were investigated in spiked aqueous solution. An incubation time of 5 min, a temperature of 20 °C, and a ratio of 1:5 wt per volume (w/v) were determined to be the optimum conditions (1 μg/mL of DON and 20 μg/L of ZEN). Subsequently, the microspheres were applied to CSL and showed high adsorption capacity for DON and ZEN. The adsorption rates of mono- and multi-mycotoxin in spiked aqueous solutions using microsphere adsorbents were studied, and a negative interaction effect was observed between DON and ZEN in the CSL system. Moreover, simple and rapid regeneration of the microspheres was achieved, and the removal efficiency of mycotoxin from CSL was almost unaffected. Thus, the low-cost and highly regenerable modified SA/β-glucan/Mt microspheres can be employed as an effective adsorbent for removing both DON and ZEN from CSL.