The Characteristics Of Alginic Acid Decomposing Bacteria And Its Cytological Effect On Laminaria Japonica

In this study, the Characteristics of growth and alginase production of strain A1 and strain A2 were examined, and the isolation and its property of extracellular enzyme-alginase of strain Al was investigated. Meanwhile, the cytological effect of infection by alginic acid decomposing bacteria was analysed in Laminaria japonica.The results were shown:1. The optimum conditions of growth and alginase production were sodium alginate 0.6-0.7% , NaC11.5%, culture temperature 20℃, pH7.5 .2. The alginase was obtained from strain Al by ammonium sulfate salting out and dialysis. The enzyme activity was stable at 4-40℃ and pH6.5-8.0.The optimum reaction temperature and pH were 35℃ and 7.0 respectively. 1mmol/L Mn2+could increase the activity of the enzyme, but Zn2+ ,Cu2+ ,Ag+ ,Pb2+ and Fe3+ could inhibit it.3. The changes of histology and cytology in Laminaria japonica were studied by artificial infection and microscopic observation.The results showed that the endodermis was infected firstly by algnic acid decomposing bacteria ; the exodermis ,pith and epidermis were infected later; the damage of endodermis was heaviest, exodermis and pith were damaged less heavier, and the effect of algnic acid decomposing bacteria infection on epidermis was not irremarkale.4.A lot of storage material was accumulated only in endodermic cells of infected laminaria japonica during infection by alginic acid decomposing bacteria; the appearance of storage particles was universally and disappeared in later stage of infection; the diameter of storage particles was from 1.5μm to 4.0μm, the average value was 2.7μm.