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Zastosowanie mikroalg spirulina sp. do oczyszczania ścieków przemysłowych zawierających metale ciężkie

100%

Chojnacka K. , Noworyta A.

tom Vol. 26, z. 2

101-110

Przedstawiono możliwości wykorzystania cyjanobakterii Spirulina sp. do oczyszczania ścieków z jonów metali ciężkich. Mikroorganizmy te wykazują odporność na zanieczyszczenie środowiska i zdolność adaptacyjną do zmieniających się warunków abiotycznych. Wiążą one metale ciężkie w procesach bioakumulacji i biosorpcji. Biousuwanie metali ciężkich odbywa się m.in. dzięki rozwiniętej powierzchni właściwej oraz możliwości wprowadzania jonów do wnętrza komórki. Dodatkowym atutem zastosowania Spiruliny jest silna alkalizacja mikrośrodowiska w bezpośrednim otoczeniu komórki, jako konsekwencja prowadzonych procesów metabolicznych. Takie warunki będą sprzyjać strącaniu wodorotlenków. Równolegle z oczyszczaniem ścieków, Spirulina może degradować zanieczyszczenia organiczne, jak również jest w stanie usuwać związki fosforu i azotu.

A possible application of cyanobacteria Spirulina sp. in the purification of waste water from heavy metal ions is presented. The microorganisms are resistant to environmental contamination and reveal an ability to adapt to the variable abiotic conditions. These microorganisms bind heavy metals as a result of the bioaccumulation and biosorption processes. Bioremoval of heavy metals takes place thanks to the developed specific area and the possibility of transferring ions into the cells. An additional asset in the application of Spirulina sp. is connected with the strong alkalinity of the micro-environment in the adjacent neighbourhood of the cell as a consequence of the undergoing metabolic processes. Such conditions will favour hydroxide precipitation. In parallel to the waste water purification Spirulina sp. can also degrade the organie contaminants and is also able to remove phosphorus and nitrogen compounds.

Peptydowe toksyny cyjanobakterii

84%

Łukomska J. , Kasprzykowski F. , Łankiewicz L. , Grzonka Z.

2002

tom [Z] 56, 1-2

57--82

This review presents chemical and biological aspects of secondary metabolites produced by cyanobacteria. The main goal of the work was to present studies related to microcystins and nodularins. Cyanobacteria (blue-green algae) growing both in freshwater and marine environment release to the medium numerous secondary metabolites. Some of cyanobacteria produce lethal toxins (cytotoxins and biotoxins). Therefore, cyanobacteria can be harmful for mammals, birds and fish, and also cause effects on human health. The secondary metabolites are the mostly derivatives of amino acids and peptides or depsipeptides. The best described among cyanobacteria toxins are the hepatotoxins: microcystins and nodularins. These toxins cause severe intrahepatic haemorrhage and hypovolaemic shock, and act as tumor promoters. Microcystins and nodularins are potent inhibitors of PP1 and PP2A protein phosphatases. Microcystins and nodularins, which are cyclic hepta- or penta-peptides, respectively, consists of various uncoded amino acid residues. The most characteristic and unique amino acid residue is Adda [(2S,3S,8S,9S,4E,6E)-3-amino-9-metoxy-2,6,8-trimethyl-10-phenyl-deca-4,6-dienoic acid]. Typical isolation of these toxins is realized by extraction combined with reversed-phase chromatography. Structure-activity relationship studies of microcystins and nodularins have revealed indispensability of Adda moiety, and two carboxyl groups of aspartic and glutamic acids, for the activity towards phosphatases. The total synthesis of both toxins represents quite a big challenge because of the necessity of preparation of Adda, as well as many other uncoded amino acids (D-erythro-b-methyl-aspartic acid, Masp; dehydroalanine, Dha, or dehydrobutyrine, Dhb, and their N-methyl derivatives etc.) prior to a final cyclization. Syntheses of Adda, the compound with four chiral centers and two specific configurations at the double bonds, were carried out mostly by the condensation of the previously obtained C1-C4 and C5-C10 fragments. Microcystins and nodularins are quite stable compounds in aqueous solution. They can be destroyed and removed by chlorination, or by treatment with ozone (Scheme 9) combined with ultrafiltration. On the other hand, microcystins and nodularins could be modified for example by esterification (Asp and/or Glu residues), transformation of guanidine moiety of arginine, Michael type addition to dehydroamino acids (Dha, Dhb). These modifications provide less toxic compounds, with interesting biological activities.