- Factors Indicating Culture Status During Cultivation of Spirulina (Arthrospira) platensis
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Choong-Jae Kim , Yun-Ho Jung , Hee-Mock Oh
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J. Microbiol. 2007;45(2):122-127.
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DOI: https://doi.org/2524 [pii]
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 Abstract
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Factors indicating culture status of two Spirulina platensis strains were monitored in a batch mode cultivation for 36 days. Changing mode in all factors showed a common turning point, indicating shift of cell or culture status. Mean biomass productivity was highly sustained until day 22, chlorophyll a concentration peaked on day 22, pH value was >12 on day 22, coil number was abruptly shortened on day 22, and floating activity was sustained at greater than 79% after day 22, indicating that day 22 is a criterion reflecting phase-transfer in cell physiology in a batch culture system. Many of these changes may have been caused by increased pH, suggesting that pH control is essential for mass production of S. platensis. Fluctuations in floating activity were likely induced by the number of cellular gas vacuoles. Consequently, coil number per trichome and floating activity of S. platensis could readily act as simple indicators for determination of culture status or harvesting time of cells.
- Simple Method for a Cell Count of the Colonial Cyanobacterium, Microcystis sp.
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Seung-Hyun Joung , Choong-Jae Kim , Chi-Yong Ahn , Kam-Yong Jang , Sung Min Boo , Hee-Mock Oh
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J. Microbiol. 2006;44(5):562-565.
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DOI: https://doi.org/2440 [pii]
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Abstract
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The cell counting of colonial Microcystis spp. is a rather difficult and error-prone proposition, as this genus forms irregularly-shaped and irregularly-sized colonies, which are packed with cells. Thus, in order to facilitate a cell count, four methods of dividing the colonies into single cells were compared, including vortexing, sonication, TiO2 treatment, and boiling. As a result, the boiling method was determined to generate the greatest number of single cells from a colony, and all colonies were found to have divided completely after only 6 min of treatment. Furthermore, no significant cell destruction, which might alter the actual cell density, was detected in conjunction with the boiling method (P = 0.158). In order to compute the cell number more simply, the relationship between the colony size and the cell number was determined, via the boiling method. The colony volume, rather than the area or diameter was correlated more closely with the cell number (r2 = 0.727), thereby suggesting that the cell numbers of colonial Microcystis sp. can also be estimated effectively from their volumes.
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