Processing cost, reducing effective specifications

The evolved enzymes were further characterized for their ability to carry out the desired pNB ester hydrolysis. Figure 4 shows the specific reaction rates for enzymes from the first four generations in 1% and 15% DMF. Each successive generation catalyst is more effective than its parent, and the best, pNB esterase 4-54B9, is 15 times more productive than wild type in 1% DMF. In 15% DMF, this enzyme makes product at 4 times the rate of the wild type enzyme in 1 % organic solvent. The impact of this improvement is not only the increased productivity of the evolved enzyme, but also in the 4-fold increase in solubility of the substrate in 15% DMF. The increased solubility reduces the size of the reactor and the downstream processes required to produce and purify a given amount of product. The 2-fold increase in enzyme expression level further reduces process costs. 

Reducing the amount of time required to properly develop, scale-up, and optimize a new process and/or product is absolutely critical and directly related to the competitive position of any business. Thus, it is important that all product development work be performed in a highly efficient and cost-effective manner. Initial product development work must identify the critical inputs to a manufacturing process and set proper specifications for these variables. In addition, if the process is shown to be robust, the tolerances on noncritical variables can be widened. 

In the previous sections, we have discussed some specific ideas for reducing material costs, and/or processing costs. However, we need to remember that material selection affects every variable in the part cost equation. While there may be ways to reduce costs in one area of the equation (often many ways), some of these efforts may actually increase costs in another area of the equation. The challenge to the design team how do you evaluate all of these effects and come up with an optimal solution ... 

Much of the experience and data from wastewater treatment has been gained from municipal treatment plants. Industrial liquid wastes are similar to wastewater but differ in significant ways. Thus, typical design parameters and standards developed for municipal wastewater operations must not be blindly utilized for industrial wastewater. It is best to run laboratory and small pilot tests with the specific industrial wastewater as part of the design process. It is most important to understand the temporal variations in industrial wastewater strength, flow, and waste components and their effect on the performance of various treatment processes. Industry personnel in an effort to reduce cost often neglect laboratory and pilot studies and depend on waste characteristics from similar plants. This strategy often results in failure, delay, and increased costs. Careful studies on the actual waste at a plant site cannot be overemphasized. 

The Chemical Process Industry (CPI) uses various quantitative and qualitative techniques to assess the reliability and risk of process equipment, process systems, and chemical manufacturing operations. These techniques identify the interactions of equipment, systems, and persons that have potentially undesirable consequences. In the case of reliability analyses, the undesirable consequences (e.g., plant shutdown, excessive downtime, or production of off-specification product) are those incidents which reduce system profitability through loss of production and increased maintenance costs. In the case of risk analyses, the primary concerns are human injuries, environmental impacts, and system damage caused by occurrence of fires, explosions, toxic material releases, and related hazards. Quantification of risk in terms of the severity of the consequences and the likelihood of occurrence provides the manager of the system with an important decisionmaking tool. By using the results of a quantitative risk analysis, we are better able to answer such questions as, Which of several candidate systems poses the least risk Are risk reduction modifications necessary and What modifications would be most effective in reducing risk ... 

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