Contents NLEE
21.2 Methods for the Manufacture of Amino Acids 384
21.2.1 Semi-fermentation 386
21.2.2 Enzymatic process 386
21.2.3 Production of amino acids by the direct fermentation 388
21.3 Production of Glutamic Acid by Wild Type Bacteria 388
21.4 Production of Amino Acids by Mutants 389
21.4.1 Production of amino acids by auxotrophic mutants 390
21.4.2 Production of amino acids by regulatory mutants 390
21.5 Improvements in the Production of Amino Acids Using
Metabolically Engineered Organisms 391
21.5.1 Strategies to modify the terminal pathways 392
21.5.2 Strategies for increasing precursor availability 393
21.5.3 Metabolic engineering to improve transport of
amino acids outside the cell 394
21.6 Fermentor Production of Amino Acid 394
21.6.1 Fermentor procedure 394
21.6.2 Raw materials 395
21.6.3 Production strains 395
21.6.4 Down stream processing 396
Suggested Readings 396
22. Biocatalysts: Immobilized Enzymes and Immobilized Cells 398
22.1 Rationale for Use of Enzymes from Microorganisms 398
22.2 Classification of Enzymes 399
22.3 Uses of Enzymes in Industry 400
22.4 Production of Enzymes 406
22.4.1 Fermentation for enzyme production 406
22.4.2 Enzyme extraction 408
22.4.3 Packaging and finishing 408
22.4.4 Toxicity testing and standardization 408
22.5 Immobilized Biocatalysts: Enzymes and Cells 408
22.5.1 Advantages of immobilized biocatalysts in general 409
22.5.2 Methods of immobilizing enzymes 409
22.5.3 Methods for the immobilization of cells 412
22.6 Bioreactors Designs for Usage in Biocatalysis 414
22.7 Practical Application of Immobilized Biological Catalyst Systems 416
22.8 Manipulation of Microorganisms for Higher Yield of Enzymes 416
22.8.1 Some aspects of the biology of extracellular enzyme production 417
Suggested Readings 419
23. Mining Microbiology: Ore Leaching (Bioleaching) by
Microorganisms 421
23.1 Bioleaching 421
23.2 Commercial Leaching Methods 422
23.2.1 Irrigation-type processes 422
23.2.2 Stirred tank processes 423