Optimization of culture conditions and characterization of a new lectin from Aspergillus niger

Lectin activity was determined on solidified medium containing agar and in broth cultures of Aspergillus niger. The fungus was found to express 16 times higher activity in broth cultures, when grown in a medium adjusted to pH 5.5 at 30°C under stationary condition. Lectin activity was found to be expressed by 6-day-old mycelial cultures with maximum activity being expressed on 9th day of incubation. The crude lectin (total titer 1280) was found to be precipitated at 50% saturation of ammonium sulphate with 2.4-fold purifi cation and 83% yield in the precipitate. The partially purifi ed lectin was found to agglutinate all human, rat, mice and pig erythrocytes. It was found to have a strong binding affinity to mucin, asialofetuin and inulin.