Mds. Saavedra et D. Voltolina, THE EFFECT OF DIFFERENT PHOTON FLUENCE RATES OF BLUE-GREEN LIGHT ON THE BIOMASS QUALITY OF A COASTAL DIATOM IN PILOT-SCALE SEMICONTINUOUS CULTURES, Scientia marina, 60, 1996, pp. 267-272
Chaetoceros sp. was kept in 101 semicontinuous cultures, compatible wi
th pilot-scale commercial production, with 50% daily dilutions. Lighti
ng was continuous, with Cool white, or blue-green fluorescent lamps, a
lone or with 6.5 mu mol m(-2) s(-1) of white light. For each type of l
ight, cultures were stabilized at different photon fluence rates and s
ampled three to five times for biomass analysis. Cell yields increased
with photon fluence rates, up to 432-498 mu mol m(-2) s(-1) for white
and between 498-565 mu mol m(-2) s(-1) for both types of blue-green l
ight. Above these fluxes, yields were light-saturated or even photoinh
ibited. For equal photon fluence rates cell concentrations were higher
in white light, but biomass yields better in mixed blue-green. Chloro
phylls a and c decreased with increasing light, while carotenoids show
ed an opposite trend. Carbon sinks were not different at low photon fl
uence rates of white and blue-green light, but the mixture of blue gre
en light and white favoured lipogenesis over glycogenesis. At high pho
ton fluence rates of blue-green light, proteogenesis increased dramati
cally at the expense of lipogenesis and glycogenesis in pure and mixed
blue-green light respectively.