The Primary Study On The Open Culture Technology Of Nostoc Flagelliforme Cells

Nostoc flagelliforme is an edible terrestrial cyanobacterium with great economic value. The aim of this study was to develop an open culture technology of N. Jlagelliforme cells for the further industrial cultivation.A N. Jlagelliforme cell strain named BC03-3 that can grow well in the alkali medium (pH>10) was screened for the further open culture. Effect of nitrate and phosphate was investigated to optimize the growth of BC03-3 in the alkali medium by Box-Wilson Central Composite Designs (CCD) and response surface analysis. The result showed that the maximum cell production of 0.887 g/L in shake flask culture was achieved in the optimized medium 2.00 g NaNO₃ per liter and 0.96 g KH₂PO₄ per liter.The results of 25 L open pond culture experiment proved that BC03-3 could grow well in the alkali medium without other algae contaminated. The paper investigated the growth of cells in the open pond and the effect of photoperiod, liquid height and aeration on the cell growth.The experiments of N. flagelliforme cells cultured on the solid medium showed that the cells could grow on the sand. The morphology picture of the cells cultured on the sand was analyzed by the computer vision techniques to get the area of cell colonies. The results suggested that the cells grown better on the sand than the thallus did. The sand of the diameter littler than 0.44 mm, the illumination intensity of 20—45 μmol/m/s and adding sodium nitrate as nitrogen source could promote the growth of cells cultured on the sand.The ability of dry and heat-resistance of N. flagelliforme cells which grew in the liquid and on the solid medium was also determined in this paper. The results showed that cells growing on the sand had the stronger tolerance to the dry and heat condition.The effect of N. flagelliforme cells on the improvement of soil was also discussed by measuring the osmosis and the water holding capacity of the soil in the dissertation. The result indicated that cells growing on the sand could be facility for the forming of soil crust and improved the soil quality possibly.This study laid the groundwork for future lower-cost, large-scale and field culture of N. flagelliforme cells.