Advanced fermentation techniques

For acetone-butanol-ethanol (ABE) fermentation, the broth contains about 25-35 g/1 of mixed solvents. Butanol concentration is usually less than 20 g/1, which makes its recovery by distillation expensive. This low butanol concentration in the fermentation broth is related to the inability of Clostridium species to produce more butanol due to solvent toxicity (Lee et al., 2008). Metabolic engineering and advanced fermentation techniques are ongoing to enhance the organisms abilities to produce and tolerate higher concentrations of butanol and increase productivity. Several integrated fermentation and recovery processes, such as fed-batch fermentation with pervaporation and continuous fermentation with gas stripping, have been reviewed elsewhere (Lee et al., 2008). 

The purpose of sample preparation is to create a processed sample that leads to better analytical results compared with the initial sample. The prepared sample should be an aliquot relatively free of interferences that is compatible with the HPLC method and that will not damage the column. The whole advanced analytical process can be wasted if an unsuitable preparation method has been employed before the sample reaches the chromatograph. Specifically, analytical work with samples from fermentation processes require a sample pre-treatment that eliminates the fermentation broth before the analytes can be injected into the chromatographic columns. This is primarily to remove macromolecular sample constituents, which easily clog the columns. Complex matrices often require a more selective sample preparation than for instance pharmaceutical solutions. In practice the choice of sample-preparation procedure is dependent on both the nature and size of the sample and on the selectivity of the separation and detection systems employed. Sample pre-treatment may includes a large number of methodologies. Ideally, sample preparation techniques should be fast, easy to use and inexpensive. In papers I and II careful sample pre-treatment was performed before all injections. 

World War II spurred much advancement in the production of penicillin, particularly the advent of submerged fermentation processes. This new technique was soon adapted to the large-scale production of bacterial proteases. The first modern detergent protease, isolated from Bacillus licheniformis, was introduced in 1962. This enzyme, a particular type of protease called a subtilase, was stable at higher temperatures, had broad substrate specificity and worked well in alkaline conditions. The appearance of this enzyme and others similar to it (i.e., subtilisins) opened up the detergent enzymes market, and by 1969, 50% of the laundry detergent products sold in the United States and Europe contained enzymes. ... 

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