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GROWTH OF VITAMIN B 12 ‐LIMITED CULTURES: THALASSIOSIRA PSEUDONANA, MONOCHRYSIS LUTHERI , AND ISOCHRYSIS GALBANA 1, 2
Author(s) -
Swift Dorothy G.,
Taylor W. Rowland
Publication year - 1974
Publication title -
journal of phycology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.85
H-Index - 127
eISSN - 1529-8817
pISSN - 0022-3646
DOI - 10.1111/j.1529-8817.1974.tb02730.x
Subject(s) - isochrysis galbana , chemostat , thalassiosira pseudonana , biology , vitamin , zoology , growth rate , food science , chemically defined medium , nutrient , botany , biochemistry , phytoplankton , algae , ecology , mathematics , genetics , geometry , bacteria , in vitro
SUMMARY The growth rates of 3 species of phytoplankton were found to be dependent on the vitamin B 12 concentrations in the media. In batch cultures, the vitamin B 12 half‐saturation constants and standard errors were 0.39 ± 0.042 μμg/ml for Thalassiosira pseudonana (clone 3H), 1.69 ± 0.24 μμg/ml for Isochrysis galbana, and 2.77 ± 1.65 μμg/ml for Monochrysis lutheri. A chemostat was used to grow T. pseudonana with vitamin B 12 as the controlling factor. In the chemostat the yield and standard deviation, 102 ± 21 × 10 4 cells/μμg vitamin B 12 , was the same as in the batch culture, 126 ± 13 ± 10 4 cells/μμg. The chemostat half‐saturation constant, 0.26 ± 0.068 μμg/ml vitamin B 12 , and maximum growth rate were in agreement with those obtained in batch cultures. Vitamin concentrations for maximum growth, rates were greater than those calculated necessary from yield data to give observed population densities similar to those in natural waters. In the sea the effect of vitamin B 12 concentration on growth rates may be complicated by low concentrations of other nutrients or the presence of inhibitors.