[Production of peroxide hydrogen in Chattonella ovata Hong Kong strain]

The growth characteristics of Chattonellea ovata Hong Kong strain (COHK) under different salinity and nutrient conditions and production of peroxide hydrogen (H2O2) in different growth phase were investigated in laboratory unialgal culture experiment. The results showed that high concentration of H2O2 was reached during the logarithmic phase from 4th to 8th days, corresponding to the maximum value of 2.91 x 10(-4) nmo x cell(-1) on the 6th day. When the N: P ratios were 16: 1, 32:1 and 64: 1, COHK possessed the relatively high growth rate and cell concentration, however, growth rate of COHK was lower with the N: P ratios of 4: 1 and 8: 1. The H2O2 concentration reached the highest (1.26 x 10(-4) nmol x cell(-1)) with the N: P ratio of 4: 1, which suggested that production of H2O2 was reversely related to the growth of COHK. The optimum salinities for COHK were 20 and 25. When the salinities were 10, 15 and 30, the growth rate of COHK was lower, showing lower and higher salinities inhibited the growth of COHK. Salinity also influenced the production of H2O2. The highest concentration of H2O2 among the experiments, 2. 2 x 10(-4) nmol x cell(-1), was observed at the salinity of 10, while there was no significant difference of H2O2 concentration from the salinity range of 15 to 30. The optimal Fe(3+) concentration for the growth of COHK was from 0.2 x 10(-8) to 1 x 10(-8) mol x L(-1), where growth rate were relatively higher. Growth rate of COHK was depressed in absence (0 mol x L(-1)) and high concentration of Fe3+ (5 x 10(-8) mol x L(-1)), with which H2O2 concentration was 0.97 x 10(-4) and 0.95 x 10(-4) nmol x cell(-1), respectively.