A non-heterocystous mutant of Aphanizomenon flos-aquae, selected by competition in light-limited continuous culture

Ecophysiological influence of light and mixing onAnabaena circinalis(Nostocales, Cyanobacteria)

“…Although our experiments were run with excess NO 3 , with no apparent requirement to fix N 2 , it is possible that the mere ability to fix N 2 requires an energy expense. This has been demonstrated previously when, under NO 3 -replete conditions, the irradiance requirements of the heterocystous cyanobacterium Aphanizomenon flos-aquae were higher than those of a non-heterocystous mutant of the same species, incapable of N 2 fixation (Zevenboom et al, 1981). Our data indicate that A. circinalis is not a cyanobacterium that requires only low ambient light conditions to out-compete other species (Zevenboom, 1986).…”

“…By comparison, the compensation irradiance of the marine diatom Phaeodactylum tricornutum was estimated to be twenty times less at 0.5 mmol m 72 s 71 (Geider et al, 1985). The high E c of A. circinalis may be due to very high energy costs of N 2 fixation, requiring production of enzymes such as nitrogenase (Zevenboom et al, 1981;Paerl, 1990;De Nobel et al, 1997). Although our experiments were run with excess NO 3 , with no apparent requirement to fix N 2 , it is possible that the mere ability to fix N 2 requires an energy expense.…”

Crop diversification can contribute to disease risk control in sustainable biofuels production

“…In algal biofuel production systems, the crop could become dominated by mutant algal strains that no longer invest energy in the production of lipids, because the mutants would likely be better resource competitors than the original high‐lipid strains. Zevenboom et al . (1981), for instance, observed that a mutant cyanobacterium that did not fix nitrogen (N) rapidly outcompeted the original N‐fixing strain in a light‐limited continuous culture.…”

Studies of the ecophysiology of algae in the laboratory of microbiology of the University of Amsterdam (summaries)

“…Among the first species studied were three cyanobacteria, viz. A. flos-aquae is a N2-fixing species that is able to grow well under nitrogen-limiting conditions, provided that sufficient ligl~t is available to meet its relatively high light energy requirement (ZEVENBOOM et al, 1981b). These species show basic differences in their physiology and in the strategy used to cope with environmental conditions.…”

“…The photosynthetic response was studied in a new incubator (ZEVENBOOM et al, 1981c), using the amperometric oxygen technique. The photosynthetic response was studied in a new incubator (ZEVENBOOM et al, 1981c), using the amperometric oxygen technique.…”