Studies on the Production of Dextral by Microorganisms

In this study, a large number of microorganisms were recovered from samples collected from different sugar facto¬ries in Egypt. Isolates showing typical morphological cha¬racteristics of Leuconostoc species were tested for their ability to produce dextran on sucrose containing media. Dextran-producers were then subjected to a number of bio¬chemical tests to assign each isolate, its proper genus and precise. As a result, a total of 54 dextran-producing Leuconostoc species (Table 5 ) have been isolated of these isolation 8 isolates were identified as Leuconostoc mesenteroides 13 isolates were identified as Leuconostoc dextranicum, and 33 isolates were identified as variants of Leuconostoc species.The, ability of these freshly isolated Leuconostoc specie to convert sucrose into dextran were compared to those of 7 reference strains known to be dextran-producers. The highest yield of dextran was .produced by a local isolate (No. 12) identified as Leuconostoc mesenteroides. This isolate showed a dextran-producing activity comparable to that of Leuconostoc mesenteroides. (ATGC 8710). This local isolate.; was recovered from the floor of mill of sugar cane syrup at Hawamdia sugar refinery factory.