Microorganisms manipulation

The stage was set for the fifth period of the industry by genetic engineering (qv) discoveries (5—7), ie, the in vitro manipulation of microorganisms. 

C. S. Stewart, T. Acamovic, FI. Gurung and A. S. Abdullah, in Manipulation of Rumen Microorganisms , Faculty of Agriculture, Alexandria University, Alexandria, Egypt, 1992, p. 150. T. Acamovic, in Developments and Ethical Considerations in Toxicology, ed. M.I. Weitzner, The Royal Society of Chemistry, 1993, p. 129. 

The refractory nature of some pollutants, notably, persistent polyhalogenated compounds, has raised problems of bioremediation of contaminated sites (e.g., sediments and dumping sites). There has been interest in the identification, or the production by genetic manipulation, of strains of microorganisms that can metabolically degrade recalcitrant molecules. For example, there are bacterial strains that can reductively dechlorinate PCBs under anaerobic conditions. 

An understanding ofthe influence ofthe chemical and physico-chemical parameters of an environment on microorganisms might allow for subtle manipulation of a formulation to create conditions which are as unfavourable as possible for growth and spoilage. 

Bacillus licheniformis produces a water-insoluble levan that has potential application as a selective plugging agent in MEOR. The microorganisms grow on sucrose, glucose, and fructose but produce levan only on sucrose. Thus plugging may be selectively controlled in the reservoir by substrate manipulation. Oil reservoirs that have a temperature of less than 55° C, a pH between 6 and 9, a pressure less than 500 atm, and a salt concentration of 4% or less are potentially suitable [1480]. 

A further application of the manipulation of microbial activity in the rhizo-sphere is their potential to remediate contaminated land. Bioremediation involves the u.se of microorganisms that break down contaminants. Radwan et al. (255) found that the soil associated with the roots of plants grown in soil heavily contaminated with oil in Kuwait was free of oil residues, presumably as a result of the ability of the resident rhizosphere microflora to degrade hydrocarbons. The use of plants as a means to accumulate pollutants such as heavy metals (256,257) to degrade hydrocarbons and pesticides (255) is already widely implemented and has proven to be successful. In some cases, there is no doubt that it is the plant itself that is responsible for the removal of the contaminants. However, in most... 

The ability to change and control the composition of the nutrient solution and the relatively small size of the microcosms used enables manipulation of environmental variables and time-course studies of rhizodeposition to be made relatively easily. The influence of nutrient availability, mechanical impedance, pH, water availability, temperature, anoxia, light intensity, CO2 concentration, and microorganisms have all been examined within a range of plant species (9). A few examples to illustrate the continued interest in examining the effect of such variables on rhizodeposition in nutrient culture are given in Table 1. 

The present chapter does not consider analysis of extracted protein biomarkers but rather focuses on strategies for rapid chemotaxonomic analysis of intact microorganisms with automated sample manipulation. Rapid means less than 5 minutes. Advantages of the application of bioinformatics and proteomics strategies for rapid identification of microorganisms include the following ... 

Among the multiple mechanisms that microorganisms have invented to acquire iron, some may lend themselves to preventive medicine by vaccination. Two such microbial strategies, manipulated to the benefit of the host, are briefly discussed here. 

Pickup R, Morgan J, Winstanley C (1993) In Edwards C (ed) Manipulating genetically manipulated microorganisms in the environment. Wiley, Chichester, New York, p 62... 

Hurdle technology Involves manipulating various growth-controlling parameters in a manner such that growth of microorganisms will not occur each parameter serves as a hurdle to microbial growth (based on Fennema, 1996). 

One way or another, the new techniques of genetic manipulation and analysis will find their way into industrial production of more efficient biologically active novel natural products from filamentous microorganisms. This process is already under way. The major pharmaceutical companies are at the forefront of progress in applying state-of-the-art techniques to strain and product development. 

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