Production of Aflatoxins by Immobilized Aspergillus flavus

Production of aflatoxins by immobilized Aspergillus flavus CAlM 127 in calcium alginate beads was affected by alg.inate concentration, amount of alginate beads as well as the spore density. An alginate concentration of 3, beads amount of 25g per 100 ml medium and spore density of about 2.4 x 10 spores/g beads showed the maximum aflatoxin activities compared with other tested variables. Free cells of A. fLevus CAIN 127 was found to produce about 8 and 20% more cell dry weight than that calculated for immobilized cell reactor in shaking and static cultures, respectively. Specific aflatoxin concentrations of the immobilized cell culture was about 1.5 times that of the free cell cultures. Also, no significant changes in aflatoxin profiles were observed by entrapment in calcium alginate beads comparing with free cell culture.in an equal concentration, sucrose, enhanced the aflatoxin production activity of the immobilized cells (relative yield = 100), followed by glucose (83%), lactose (42%), then starch (30%). An optimum sucrose concentration in the fermentation medium should be ranged between 85-100 g/l. A nitrogen feed containing 10 gil peptone plus leg/l asparagine led to the highest activity of such immobilized cell reactors.