Light and oxygen stress in Spirulina platensis (cyanobacteria) grown outdoors in tubular reactors

Abstract

and Tomaselli, L. 1996, Light and oxygen stress in Spirulina platensis (cyanobacteria) grown outdoors in tubular reactors, -Physiol, Plant, 97;[175][176][177][178][179] As the effects of light and oxygen stress in algae on mass culture has not been intensively studied, we investigated them in Spiruiina platensis under outdoor conditions in controlled tubular reactors where the respective roles of each stress can be distinguished. It was observed that exposure of this cyanobacterium at two oxygen concentrations (ca 20 and 53 mg !"') caused very little change in the ratio between variable and maximum fluorescence (F^/F^,) during the day even when the culture was grown at higher oxygen concentration (about 7% lower in the evening than in the moming). Vice-versa, when the photochemical efficiency of PSII (photon yield, O,) was measured, a reduction of about 20% was observed. Neither the F,/F^ ratio nor the <t>, of the culture grown at the lower oxygen concentration changed significantly during the day. The dally productivity of the culture exposed to the higher oxygen concentration was reduced by about 20%, Laboratory cultures but>bled with air or pure oxygen under continuous light showed a similar response; i,e,, a smaller decrease in F,/F^ (11%) than in the <b^ (56%) after 4 h. After 32 h of culture in pure oxygen, a total lysis of the cells occurred. Our results support the hypothesis that photoinhibition and photooxidation, two traditionally linked terms, although often closely associated under similar environmental conditions, may comprise two types of stress with different sites of inhibition.

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“…For instance, when DO was elevated to a level higher than 13 mg/L, the final biomass concentration was substantially reduced in culture of Chlorella sorokiniana (Ugwu et al 2007), while cell death occurred only when DO reached 36 mg/L for Spirulina platensis Vonshak et al (1996). It is interesting that Euhalothece sp.…”

What is the role and nature of programmed cell death in phytoplankton ecology?

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Nostoc sphaeroides Kützing, an excellent candidate producer for CELSS

“…Sprulira sp. oxygen evolution rate is between 110 and 140 lmol O 2 mg À1 Chl a h À1 with the PPFD of 40 lmol photons m À2 s À1 (Vonshak et al, 1996;Torzillo et al, 1998;Jimenez et al, 2003). Compared with Spirulina sp.…”