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句子与段落翻译： 1. The ligated pasmid mixture is introduced into bacterial cells specially treated so that they take up DNA in a process termed transformation. In most cases E.coli is the preferred host with the advantages that calcium treated cells are highly transformable, the molecular biology of this bacterium is well understood and a variety of plasmid and phage vectors are available. Moreover, E. coli transcribes and translates most Gram-positive and Gram-negative genes with the exception of some actinomycete genes. 2. The insertion site within the vector is located within a tetracycline resistance gene. Transformants that are ampicillin resistant but tetracycline sensitive therefore represent cells containing a hybrid plasmid(insertion inactivation). 3. From this example it become clear that，as in most downstream operations，the objective of the processing operation must be clearly stated． 4. Several groups have studied acid accumulation by different strains, but the biochemical mechanism has not yet been completely elucidated. 5. Methods for oxygen analysis by paramagnetic procedures and carbon dioxide measurement by infrared analysis suffer from the disadvantage of calibration drift and slow response time. 6. In the larger sizes of vessel, a continuous steam-sterilized section of the bearing prevents such contamination, with the additional benefit of lubrication by sterile condensate. 7. The most recent(1984) selling price for the only commercial bacterial SCP product is approximately $600 per tonne for animal feed application in Western European markets. 8. Utilities costs including water, electricity and steam, labor costs, maintenance and depreciation, taxes and insurance, working capital, interest, and desired profit must also be taken into account. 9. The estimated 1976 costs of $70 million for 50,000-70,000 tonnes per year capacity would be substantially greater today. 10. The most recent(1984)selling price for the only commercial bacterial SCP product is approximately $600 per tonne for animal feed application in Western European markets. The extent to which this product can compete with soybean meal or fish meal depends upon current delivered prices for these commodities in Western Europe. 11. The annual production of monosodium L-glutamate, produced exclusively by fermentation, exceeds 400,000 tonnes. 12. The establishment of L-glutamic acid fermentation provided a significant impetus to the development of microbial production of primary metabolites. Encouraged by the establishment of the L-glutamic acid fermentation, various research projects have been carried out in the attempt to isolate wild strains or derive genetic mutants producing various kinds of amino acids. As a result, almost all of the amino acids are now commercially produced by fermentation. 13. In wort production, the temperature is held constant at about 65℃ to allow enzyme conversion and wort extraction. 14. In addition to various fermentation conditions, cell yield is also affected by the presence of metabolic by-products and other substances in the fermentation system. 15. In this way, no CO2 should be expended during active citrate production as CO2 released during oxidative decarboxylation of pyruvate to acety-CoA should be utilized in the conversion of pyruvate to oxaloacetate. 16. Yeast grown specially as a foodstuff for humans, farm animals or domestic pets represent one of the most promising applications of the growth of microbial biomass as food. In particular, during the 1914-1918 and 1939-1945 world wars and their aftermath, the aerobic growth of yeast cells produced food protein more rapidly than conventional agriculture. 17. The often quoted comparison that a 0.5 t bullock synthesizes less than 0.5 kg of protein every 24 h, but 0.5 t of soy beans produces the equivalent of 40 kg protein every 24 h and 0.5 t of yeast fenerates 50 t in that time, illustrates well the main advantage of microbial SCP. 18. On the other hand, the necessary technology is more complex, difficulties have been encountered with the high purine content of cells and indigestibility of cell walls and SCP is not as acceptable as animal protein in the diet. 19. The use of microorganisms to produce chemicals and fuels dates back to the production of ethanol and acetic acid in prehistoric times. 20. Vinegar, the aqueous solution of acetic acid, is produced in fermentation by oxidation of a dilute ethanol solution. 21. After emptying and rinsing from the previous batch,mash at 13-17 wt % sugar is pumped to the fermenters. Once 20 % full, the inoculum is added to allow growth during the remainder of the filling cyclem, which can last 4-6 h. 22. Wastes occur in all three states, i.e. solids, liquids and gases. They are derived from three primary sources: urban, agriculture, and industry. By weight and volume,solid wastes, i.e. urban refuse, crops and food processing wastes, and manures, are the most significant of all wastes. 23. In general, solid wastes are either burnt for energy, thermally decomposed, anaerobically degested to create methane or other combustible gases, disposed off in landfill or biologically converted to a variety of products. 24. Liquid wastes are the most troublesome, because they often involve non-retractable chemicals. Further, they are eventually returned to the environment through surface waters. 25. An important common feature in the production of all these alcoholic beverages is the use of yeast to convert sgars to ethanol. 26. The production process was designed to handle potato-processing waste but suffered from problems of lack of substrate supply continuously. 27. However, there still remains room for improvement. 28. To satisfy the expected large market for feed-supplements, the present process must be further improved. 29. Enzymatic production of L-aspartic acid from fumaric acid and ammonia by the action of aspartase can be classified as either batch or continuous processes. 30. Following solid-liquid separation of the fermentation whole broth, each of the two fractions may be further processed or run to waste as appropriate. 31. Many biotechnology products are soluble and are present either in the clarified extracellular culture fluid or in the intracellular loluble fraction. These products may be forther processed and purified using molecular separation techniques which exploit property defferences such as size, charge, solubility, volatility, biological affinity, etc. 32. Gel filtration and affinity chromatography are useful laboratory methods which have not so far been applied to large scale production. 33. Proteins, enzymes, immunological reagents and blood products may all be obtained in