Bacterial strains purification

The bacterial strains were submitted to the National Collection of Microorganism Cultures of the Pasteur Institute (CNCM) and included R. erythropolis CNCM 1-2204, -2205, -2207, and -2208, and/or R. rhodnii 1-2206. The activity of the microorganisms includes a selective attack on the carbon-sulfur bonds in the organic molecules without significant alteration of the carbon atom structure. As usual, strains were isolated and subjected to successive enrichment phases, in media containing various sources of carbon and DBT as the only sulfur source, then a purification of the enhanced culture led to the fifteen DBT specific strains. From those strains, a subset of ten strains was selected... 

Figure 2.36. Schematic layout of photobiological hydrogen production plant with auxiliary plants for production of modified bacterial strains and for hydrogen gas purification (Serensen, 2004c).

Natural product extracts and bacterial culture collections do not necessarily work well together on drug discovery platforms. The separation, identification, characterization, scale-up, and purification of natural products for large-scale libraries suitable for these HTS are daunting, and rational arguments for the selection of organisms and/or natural product molecules are often absent, especially given the poor taxonomic characterization of strains in natural product bacterial strain collections. 

PHA is accumulated intracellularly in Gram-negative bacterial strains and normally its recovery after the fermentation include several steps - briefly these are (i) the separation of cells from the fermentation broth by centrifugation (ii) after that, the bacterial cells are pre-treated by heat, freeze dried, or salted, before extraction to avoid polymer degradation (iii) the PHA is therefore extracted, normally by using chlorinated solvents or other methods such as enzymatic digestion or mechanical cell disruption and (iv) PHA purification. The process of PHA recoveiy is shown in Figure 2.9. 

Sebastian J, Kolattukudy PE (1988) Purification and characterization of cutinase from a fiuorescent Pseudomonas putida bacterial strain isolated from phyllosphere. Arch Biochem Biophys 263 77-85... 

Currently Procter Gamble and Kaneka are working on new GM micro-organisms to increase production yields and decrease its price. The present Procter Gamble/Kaneka cost target is 1.2/kg by 2007, with 0.4/kg in the long term (on a 50,000 tonnes/year basis, with new bacterial strains and new separation/purification techniques). 

In recent years, intensive research has been carried out on bacterial production of PHA and a great effort is underway to improve this proeess (Khanna and Srivastava, 2005). However, the production cost of PHA is still far above the priee of conventional plastic (Verlinden et al., 2007). In order to make the PHA produetion process economically attractive, many goals have to be addressed simultaneously. Recombinant bacterial strains are being developed to achieve high substrate conversion rate. A more efficient fermentation process (Grothe et al., 1999 Patwardhan and Srivastava, 2004) better recovery and purification processes (Jung et al., 2005) and the use of inexpensive substrates (Daniel et al., 2006) can also substantially reduce the production cost. 

Detergent enzymes are produced by bacterial strains, conditioned to resist alkaline pH s and therefore to produce alkaline-resistant enzymes. Moreover, they are exocellular enzymes, secreted by the bacteria into the surrounding medium. Thus, they can be isolated without breaking the bacterial cells. That makes the purification process easier and less costly. These bacterial proteases are less specific and will degrade almost all kinds of proteins. 

Incubation of sonic extracts of several A. aerogenes bacterial strains with ATP, ribose 5-P, glutamine, and acetyl-P yielded an arylamine and an imidazole. When these incubations were performed with either ribose 5-P-l-Ci<, AMP-8-C, or adenine-2-C as an additional reactant, the arylamine and the imidazole accumulated in sufficient amounts to be isolated and identified. After purification the imidazole was shown to be... 

Wieser M, B Wagner, J Eberspacher, F Lingens (1997) Purification and characterization of 2,4,6-trichlorophenol-4-monooxygenase, a dehalogenating enzyme from Azotobacter sp. strain GPl. J Bacterial 179 202-208. 

Small FJ, SA Ensign (1997) Alkene monooxygenase from Xanthobacter strain Py2. Purification and characterization of a four-component system central to the bacterial metabolism of aliphatic alkenes. J Biol Chem 272 24913-24920. 

Larkin MJ, CCR Allen, LA Kulakov, DA Lipscomb (1999) Purification and characterization of a novel naphthalene dioxygenase irom Rhodococcus sp. strain NCIMB 12038. J Bacterial 181 6200-6204. 

Haddock ID, DT Gibson (1995) Purification and characterization of the oxygenase component of biphenyl 2,3-dioxygenase from Pseudomonas sp. strain LB400. J Bacterial 177 5834-5839. 

Lee J-Y, L Xun (1997) Purification and characterization of 2,6-dichloro-p-hydroquinone chlorohydrolase from Flavobacterium sp. strain ATCC 39723. J Bacterial 179 1521-1524. 

Streptokinase is a 48 kDa extracellular bacterial protein produced by several strains of Streptococcus haemolyticus group C. Its ability to induce lysis of blood clots was first demonstrated in 1933. Early therapeutic preparations administered to patients often caused immunological and other complications, usually prompted by impurities present in these products. Chromatographic purification (particularly using gel filtration and ion-exchange columns) overcame many of these initial difficulties. Modern chromatographically pure streptokinase preparations are usually supplied in freeze-dried form. These preparations (still obtained by non-recombinant means) often contain albumin as an excipient. The albumin prevents flocculation of the active ingredient upon its reconstitution. 

Li, T. and Rosazza, J.P.N. Purification, characterization, and properties of an aryl aldehyde oxidoreductase from Nocardia sp. strain NRRL 5646. J. Bacterial., 1997, 179, 3482-3487. 

---