Carotenoid Production by Streptomycin-Bleached Euglena

SYNOPSIS. Streptomycin-bleached Euglena gracilis, strain Z, was cultivated under conditions which yielded good growth rates and high cell densities. Dividing cells produced only small amounts of carotenoid. After the cessation of cell division the carotenoid content of the cells increased rapidly. During the major period of carotenoid synthesis the cell number remained unchanged but the packed cell volume decreased. Some similar observations on carotenoid production by normal dark-grown Euglena are noted.