Biosorption

from Wikipedia, the free encyclopedia
This article was entered due to deficiencies in the science quality assurance . This is done in order to bring the quality of the articles from the overarching subject areas of the natural sciences to an acceptable level. Articles that cannot be significantly improved can be deleted. Help fix the shortcomings in this article and join the discussion .

The biosorption describes the enrichment of certain substances ( heavy metals or radionuclides ) to biological material, for example to algae , bacteria , yeasts , lignins , celluloses , alginates , and many others. The mechanism of action is either a metabolic process , when the substance is enriched in the metabolism of a living organism, or a physico-chemical process, when the substances bind to cell structures. Biosorption is used, for example, to isolate heavy metals from wastewater.

definition

The term biosorption has a multidimensional character, its definition is difficult and it has changed in the last few decades due to the variety of mechanisms that contribute to the overall process, depending on the sorbate and the biosorbent, on the environmental conditions and on the metabolic processes in the case of living Organisms evolved.

Some publications suggest that most researchers define biosorption as a passive and metabolically independent process that occurs either through dead biomass or fragments of cells and tissues. Others also include the accumulation of substances by living cells by means of active and metabolism-dependent processes. It is important to emphasize that the two operations can overlap, which can create additional confusion when using the names.

history

The use of microbes to accumulate heavy metals was observed in the early 18th and 19th centuries. The earliest technical application of biosorption techniques was sewage and waste treatment. The first quantitative study of copper biosorption by fungal spores of Tilletia tritici and Ustilago crameri was carried out by L. Hecke in 1902. Similar studies were also published by F. Pichler and A. Wobler in 1922, in which the uptake of silver , copper , cerium and mercury by corn waste was assessed. The first article on biosorption was published in 1951.

extent

The extent of the biosorption of a certain heavy metal is described by the so-called bioconcentration factor (BCF). Depending on the type of microorganism and metal, the BCF can be between 10 2 and 10 5 . Enrichments of several powers of ten - especially of radionuclides - are possible. One example is Rhizopus arrhizus , which binds about 200 mg uranium or thorium per g dry matter. The differences are considerable both between different microorganisms and in the sorption capacity of a particular microorganism for different metals. Biosorption is particularly effective at low heavy metal concentrations (ppb - ppm, corresponding to pg / l - mg / l), where physico-chemical processes fail or are at least costly. The biosorption of heavy metals is generally reversible, e.g. B. by adding complexing agents; thus bioabsorbers that can be regenerated multiple times can be realized.

The resistance of the microorganisms to the mostly toxic heavy metals is important. It is mostly genetic and controlled by plasmids .

Mechanisms

At least two mechanisms are responsible for biosorption:

  1. The binding of positively charged metal ions to negatively charged groups on the surface of microorganisms. This process is influenced by various chemical and physical factors. Surface-active polymers (e.g. from marine Pseudomonas species, used to obtain cobalt , nickel , zinc , etc.) or other compounds excreted by microorganisms (e.g. emulsan from Acinetobacter calcoaceticus RAG-1, binding of Uranium) form complex bonds with metals . Gold and platinum metals can be enriched with the help of C-heterotrophic microorganisms (bacteria / fungi) via organic complex compounds.
  2. The accumulation of metals in the cytoplasm of cells. This process is not influenced by chemical or physical factors, but is dependent on metabolic processes ( membrane transport ) and is therefore linked to intact, living cells.

“Bioprecipitation” represents a special form. This is understood to mean the biologically conditioned formation of poorly soluble precipitates. An important example is the sulphide precipitation of heavy metals by bacterially formed hydrogen sulphide . Anaerobic, sulfate-reducing bacteria, e.g. Desulfovibrio desulfuricans , Desulfotomaculum, Desulfobacter, Desulfosarcina and Desulfonema species, use sulfate as the terminal electron acceptor of their energy metabolism, in which organic substances or molecular hydrogen flow in as starting materials and thereby hydrogen sulfide is formed. By deliberately bringing about this desulfurization , e.g. B. by adding organic substances and / or by creating anaerobic conditions, heavy metals can be removed from so-called " acid mine water " and the water can be detoxified.

See also

Web links

Individual evidence

  1. ↑ Biosorption - an overview | ScienceDirect Topics. Retrieved February 2, 2020 .
  2. ↑ Shamim, Saba. (2018). Biosorption of Heavy Metals. doi : 10.5772 / intechopen.72099 .
  3. ↑ a b Filomena Costa and Teresa Tavares (July 18th 2018). Biosorption of Multicomponent Solutions: A State of the Art of the Understudy Case , Biosorption, Jan Derco and Branislav Vrana, IntechOpen, doi : 10.5772 / intechopen.72179 .
  4. ↑ Arti Hansda, Vipin Kumar and Anshumali, 2015. biosorption of Copper by Bacterial Adsorbents: A Review. Research Journal of Environmental Toxicology, 9: 45-58. doi : 10.3923 / rjet.2015.45.58
  5. ↑ Jan Derco, Branislav Vrana: Biosorption . BoD - Books on Demand, 2018, ISBN 978-1-78923-472-5 , pp. 55 ( books.google.de ).
  6. ^ A b Franz-Josef Dreyhaupt: VDI-Lexikon Umwelttechnik . Springer-Verlag, 2013, ISBN 978-3-642-95750-5 , pp. 226 ( limited preview in Google Book search).
  7. ↑ a b c d Lexicon of Biochemistry: Biosorption i Lexicon of Biochemistry , accessed on June 17, 2020
  8. ^ Müfit Bahadir, Harun Parlar, Michael Spiteller: Springer Umweltlexikon . Springer-Verlag, 2013, ISBN 978-3-642-97335-2 , p. 524 ( limited preview in Google Book search).