Mechanisms of solvent toxicity for microorganisms

The toxicity of organic solvents or hydrophobic substances for microorganisms depends mainly on their effects on biological membranes - similar to membrane effects of several anesthetics. This concerns especially effects on cytoplasmatic membranes. The following main changes of membrane structures and functions have been observed  

The extent of solvent toxicity to microorganisms is determined by various factors  

The toxicity and the affinity of solvents to cell structures increase with hydrophobic properties of solvents, e.g., high toxicities with P, values of l-S. The partition coefficient correlates with the membrane-buffer partition coefficient between membrane and aqueous system. They also depend on membrane characteristics. 

The toxicity of solvents for microorganisms shows positive and negative consequences, e.g.  

3 Adaption of microorganisms to soivents - soivent-resistant microorganisms 

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As a basic in B LMs for the wastewater treatment the author presents two-phase partitioning bioreactors. He presents the main criteria which must be considered in the selection of the LM solvent biocompatibility (toxicity of the solvent to the microorganism), bioavailabihty (resistance of the solvent to biodegradation by the microorganism used), immiscibility in the aqueous phase, high solubility of pollutant in the solvent, favorable mass-transfer characteristics, etc. Biodegradation mechanisms and kinetics are discussed. Apphcations of bioreactors in wastewater treatment in laboratory, phot, and industrial scale are reviewed. Potential applications are considered also. 

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