Solvent-tolerant bacteria

In this volume not all stress types are treated. Various aspects have been reviewed recently by various authors e.g. The effects of oxygen on recombinant protein expression by Konz et al. [2]. The Mechanisms by which bacterial cells respond to pH was considered in a Symposium in 1999 [3] and solvent effects were reviewed by de Bont in the article Solvent-tolerant bacteria in biocatalysis [4]. Therefore, these aspects are not considered in this volume. Influence of fluid dynamical stresses on micro-organism, animal and plant cells are in center of interest in this volume. In chapter 2, H.-J. Henzler discusses the quantitative evaluation of fluid dynamical stresses in various type of reactors with different methods based on investigations performed on laboratory an pilot plant scales. S. S. Yim and A. Shamlou give a general review on the effects of fluid dynamical and mechanical stresses on micro-organisms and bio-polymers in chapter 3. G. Ketzmer describes the effects of shear stress on adherent cells in chapter 4. Finally, in chapter 5, P. Kieran considers the influence of stress on plant cells. 

Ramos JL, E Duque, J-J Rodrlguez-Herva, P Godoy, A Haidour, F Reyes, A Fernandez-Barrero (1997) Mechanisms for solvent tolerance in bacteria. J Biol Chem 272 3887-3890. 

Heipieper, H.J., Neumann, G., Cornelissen, S. and Meinhardt, F. (2007) Solvent-tolerant bacteria for biotransformations in two-phase fermentation systems. Applied Microbiology and Biotechnology, 74, 961-973. 

Sardessai, Y.N. and Bhosle, S. (2004) Industrial potential of organic solvent tolerant bacteria. Biotechnology... 

Recently, organic solvent tolerant bacteria, a novel group of extremophilic microorganisms that combat these destructive effects and thrive in the presence of high concentrations of organic solvents as a result of various adaptations, are being explored for their potential in industrial and environmental biotechnology [29],... 

Ramos, J. L., E. Duque, J.-J. Rodriguez-Herva, P. Godoy, A. Haidour, F. Reyes, and A. Fernandez-Barrero, Mechanisms for solvent tolerance in bacteria , J. Biol. Chem., 272, 3887-3890 (1997). 

Sardessai Y and Bhosle S. Industrial Potential of Organic Solvent Tolerant Bacteria. Biotechnol Prog 2004 20 655-660. 

Inoue, A., Horikoshi, K. (1991). Estimation of solvent-tolerance of bacteria by the solvent parameter log P. Journal of Fermentation and Bioengineering li . 194-196. 

Fernandes, P., Sommer Perreira, B., Sampaio Cabral, J. M. (2003). Solvent tolerance in bacteria Role of efflux pumps and crossresistance with antibiotics. International Journal of Antimicrobial Agents 22 . 211-216. 

Ramos, J.L., Duque, E., Gallegos, M.T., Godoy, P., Ramos-Gonzalez, M.I., Rojas, A., Teran, W., and Segura, A. (2002) Mechanisms of solvent tolerance in gram-negative bacteria. Anna. Rev. Microbiol., 56, 743-768. 

T., Bernal, P., Munoz-Rojas, ]., and Ramos, J.L. (2012) Solvent tolerance in Gram-negative bacteria. Curr. Opin. Biotechnol, 23 (3), 415-421. 

Unlike Gram-positive bacteria, Gram-negative bacteria such as Pseudomonas have an outer membrane. The outer membrane has been shown to play a role in the protection of the cell from solvent toxicity. Ions such as Mg or Ca stabilize the organization of the outer membrane and contribute to solvent tolerance. Low cell surface hydrophobicity caused by changes in the lipopolysaccharide (LPS) content has been reported to serve as a defensive mechanism. " It has also been reported that the porins which are embedded in the outer membrane are relevant to solvent tolerance. ... 

The applications of solvent-tolerant strains in microbial production processes are at present limited, but two strategic options are currently available to use such bacteria. Relevant genes can be introduced into solvent-tolerant organisms in order to produce the required product. This approach has been followed successfully by J. Wery in our laboratory who employed an 1-octanol-aqueous system. Methylcatechol was produced from toluene by solvent tolerant P. putida S12. Alternatively, the efflux pump can be expressed in a suitable solvent-sensitive host which would then be more tolerant for a particular solvent. 

Other benefits may arrive from solvent-resistant bacteria. Ogino et al. isolated Pseudomonas aeruginosa LST-03 whieh ean grow in organic solvents with logPo/w >2.4 and secrets organic solvent-stable lipolytic enzymes. They were able to purify an organic solvent-stable protease which was more stable than the commercially available proteases. Hence, solvent-tolerant strains have become a source for new enzymes. 

Many important fine chemicals, including catechols, phenols, aldehydes and ketones, low molecular epoxides and diepoxides, medixun-chain alcohols, and terpenoids fall within the range of 1 < log Pq/w < 4. The discovery of solvent-tolerant bacteria leads to the new possibility of biocatalytic reaction systems containing organic solvents. By using solvent-tolerant bacteria, a variety of fine chemicals can be formed in microbial production processes. 

Hayashi, S. Kohayashi, T Honda, H. Simple and rapid cell growth assay using tetrazolium violet coloring method for screening of organic solvent tolerant bacteria. J. Biosci. Bioeng. 2003, 96, 360-363. 

---