biochemistry of geo microbes & biomineralization
TRANSCRIPT
BIOCHEMISTRY OF GEO MICROBES BIOMINERALIZATION Submitted to: Submitted by:Dr. S.K. Srivastva Suman 15MSCBC003 MSc Biochemistry 3rd semester
CONTENT Introduction Role of geomicrobes as geoactive agents Biomineralization Types of biomineralization Biologically induced mineralization Microbes involves in BIM Biologically controlled mineralization Method of BCM Microbes involves in BCM Process of magnetite in Magnetotactic bacteria Significance of Biomineralization
INTRODUCTION Microbes play geo active role in biosphere . All kind of microbes include prokaryotes and Eukaryotes
, their symbiotic association etc. contribute geological phenomena and many geological processes like metal and mineral transformation.
The ubiquity and importance of microbes in biosphere processes.
ROLE OF GEOMICROBES AS GEOACTIVE AGENTS
Key topics within the geomicrobiology frame work includes biogeochemical cycles of the elements, mineral formation, mineral deterioration(which can include such as subjects as bioweathering and processes leading to soil & sediment formation) and chemical transformation of metals, metalloids and radionuclides.
BIOMINERALIZATION Definition: A process by which living forms influences
the precipitation of mineral materials. The process creates heterogeneous accumulation
composites composed of biogenic and inorganic compounds.
Living forms produces carbonates phosphate oxalates silica iron or sulfur containing minerals.
Biomineralization occurs extracellular involves often crystalline, materials forming on the outer wall of the cell.
Intracellular biomineralization is mineral formation within the cell such as calcite formation for the group of the algae the Coccolithophorides.
TYPES OF BIOMINERALIZATION
Mineral synthesis can be categorized into two categories: Biologically Induced Mineralization Biologically Controlled Mineralization
BIOLOGICALLY INDUCED MINERALIZATION
Mineral forms by this process, generally nucleate & grow extracellulary as a result of metabolic activity.
Subsequent chemical reaction involving metabolic by products such as O2, HCO-3, etc.
In some the organisms secrete one or more metabolic products that react with ions or compounds in the environment resulting on the subsequent deposition of mineral particles.
MICROBES INVOLVES IN BIM No of microbes involves in biologically
Induced mineralization process . Some of microbes are: Mycorrhiza, Lichen,
Cynobacteria like Synechococcus spp., Bacteria like Leptospirillum spp. , Thiobacillus
ferroxidans, sulfur reducing bacteria etc. Archea like sulfolobus spp., Acidimicrobium
ferroxidans spp., acidianus spp., Metallosphaera spp., sulfurococcus yellowstonesis. etc.
EXAMPLES OF MINERAL BY BIM Calcium Carbonate: Carbonate are long lived locally abundant
sediments, promotes calcite/ Aragonite and Dolomite precipitates.o These precipitates occurs in, on or around the organic matter of the
cells that they produce.o These carbonate minerals presents on lake, sea floors etc. Chemical Reaction: Ca2+ + 2HCO3- ↔ CaCO3 + CO2 + H2O Microbial populations involved in this mineral formation are :
Cynobacteria, Algae such as green, brown, red algae and Chrysophytes such as Coccolithophores & few protozoa like Forminifera.
OTHER EXAMPLES OF MINERALS FORMED BY BIM
BIOLOGICALLY CONTROLLED MINERALIZATION
Microbes exerts considerable active control over all aspects of the nucleation and mineral growth stages.
A specific site within the cytoplasm or the cell wall is sealed off from the external environment creating geochemical condition independently.
2 common methods of space delineation can occur.1. Involve the development of intercellular space between
cells.2. Formation of intracellular deposition vesicles.
METHOD
Once the cellular compartment is formed
the cells sequestering specific ions of choice
transferring them to mineralization site , where conc. Increased until saturation achieved
Super saturation are then regulated by managing the rate at which mineral constituents are brought into the cell via specific transport enzymes.
CONTINUE
nucleation controlled by exposing organic ligands with distinct sterochemical and electrochemical properties
tailored to interact with the mineralizing ions.
MICROBES INVOLVE IN BCM
Many microbes involves in biologically controlled mineralization process
These are: Magnetotactic bacteria Diatoms Emiliania huxleyi etc.
EXAMPLE OF MINERAL BY BCM
Magnetite: Magnetite formation done by Magnetotactic
Bacteria, which is microaerophilic, posses bidirectional motility and contain membrane bounded a no of intracellular, linear arranged magnetosomes , house mineral grains.
The actual crystallization of magnetite then involves the reaction of the ferric hydroxide with more Fe2+:
Fe2+ + 2OH− + 2Fe(OH)3→Fe3O4 + 4H2O
IMAGE OF MAGNETOTACTIC BACTERIA
PROCESS OF MAGNETITE IN MAGNETOTACTIC BACTERIA
CONTINUE
This is accomplished by cell synthesis of specific receptor proteins.
Firstly they recognized to Fe(III)- siderophores then to with the aid of other transport proteins.
These proteins guide the coordinated Fe(III) to plasma. Specific magnetosome associated proteins play a role in
vesicle formation prior to biomineralization.
SIGNIFICANCES OF BIOMINERALIZATION
Great significance in scientific and commercial application
Metal sorption, precipitate can be important and useful in metal and radionuclide removal during bioremediation metal radionuclide contaminate water .
Efficiently removal of Fe and Mn ions from water in waste water treatment plants.
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