Construction of high-guluronate-containing-alginate producing mutant of Pseudomonas sp.QDA
富含古罗糖醛酸的褐藻多糖生产菌株的构建

The effects of ferrous ion on ichthyotoxic red tide organism Heterosigma akashiwo were studied.Two ferrous ion forms,Fe(NH4)2(SO4)(Fe1) and FeSO4(Fe2),were added to the culture under three different concentrations(high group,150 nmol/L;low group,50 nmol/L,naught group,0 nmol/L),changes of population,polysaccharide,chlorophyll a and c and nitrate level in culture medium were investigated.The results indicated that ferrous concentration affects the population crash,a ferrous deficient group(Fe0) can maintain a longer life and a higher density than the higher iron groups during the population crash.The cellular polysaccharide content in Fe1 group is significantly higher than that in Fe2 group both at stationary phase and crash phase.From stationary phase to crash phase,the polysaccharide content in each group increased,the highest increase appeared in Fe2.Increase of ferrous ion is helpful to the accumulation of chlorophylls.The different formations of ferrous ion affect the accumulations of polysaccharide and chlorophylls but have no obvious effects on the population growth rate and nitrate level.