25 research outputs found
Avaliação sensorial de pães de fermentação natural a partir de culturas starters inovadoras
Evaluation of Kluyveromyces marxianus FII 510700 grown on a lactose-based medium as a source of a natural bioemulsifier
Optimization of Ethanol Production from Whey Through Fed-batch Fermentation Using Kluyveromyces Marxianus
Optimisation of culture conditions and development of a novel fed-batch strategy for high production of β-galactosidase by Kluyveromyces lactis
Substrate consumption and beta-galactosidase production by Saccharomyces fragilis IZ 275 grown in cheese whey as a function of cell growth rate
Fermentation of cheese whey powder solution to ethanol in a packed-column bioreactor: effects of feed sugar concentration
Use of superoxide as an electron shuttle for iron acquisition by the marine cyanobacterium Lyngbya majuscula
Reduction of iron from the ferric state to the ferrous state is one strategy employed by microorganisms in near-neutral environments to increase its biological availability. In recent years, the existence of mobile reducing agents produced by microorganisms to promote iron reduction,known as electron shuttles, has been demonstrated. Production of electron shuttles has been shown for several organisms, employing a variety of mostly organic molecules as the electron carrier. Here we show that the coastal cyanobacterium Lyngbya majuscula produces iron-reducing superoxide radicals (O-2(center dot)-) and that this facilitates increased iron uptake. We suggest that superoxide is a useful electron shuttle because it reacts rapidly and almost indiscriminately with Fe(III)-organic complexes and its precursor, dissolved oxygen, is ubiquitous in the photic zone. We further suggest that, for these reasons, the generation of superoxide by marine oxygenic photosynthetic microorganisms and its use in facilitating iron uptake may be a reasonably widespread process