Overproduction, waste

Situated as it is between glycolysis and the electron transport chain, the TCA cycle must be carefully controlled by the ceil. If the cycle were permitted to run unchecked, large amounts of metabolic energy could be wasted in overproduction of reduced coenzymes and ATP conversely, if it ran too slowly, ATP would not be produced rapidly enough to satisfy the needs of the cell. Also, as just seen, the TCA cycle is an important source of precursors for biosynthetic processes and must be able to provide them as needed. 

In humans, uric acid is the end product of the degradation of purines. It serves no known physiologic purpose and is regarded as a waste product. The size of the urate pool is increased severalfold in individuals with gout. This excess accumulation may result from either overproduction or underexcretion. 

This is the waste coming from the production of more units than demanded. The optimum number of products to be produced must balance the demand, including that in high season periods, the cost of holding the stocks in the warehouse and the cost of setting up the production to produce one lot of the product. In terms of an analytical laboratory, overproduction could be interpreted as any activity that is not necessary for customer service or for adding value to the experience and knowledge of the laboratory. There is no need to analyse too many samples unless we have reasons to do so. Furthermore, there is no need to perform more analyses than necessary. Too many analytical results are a waste. For example, the optimum number of replicates must balance the need for statistical evaluation. 

Normally, the rate of production of lead azide is geared to the rate at which it can be incorporated in explosive trains. In this manner the total quantity on hand is minimized and is broken down into small lots and packaged so that the accidental detonation of one component will be less likely to result in the sympathetic detonation of large stores. However, during the South East Asia conflict a substantial overproduction of lead azide occurred, and bulk quantities were produced far in excess of normal rates. This situation required a special awareness of three problems which, although always of concern, do not normally assume such proportions. These were the problems associated with bulk storage and handling of the finished product with the accumulation of hazardous waste... 

In humans, uric acid is the end product of the degradation of purines. Uric acid serves no known physiologic purpose and therefore is regarded as a waste product. In lower animals, the enzyme uricase breaks down uric acid to the more soluble allantoin, and thus uric acid does not accumulate. Gout occurs exclusively in humans in whom a miscible pool of uric acid exists. Under normal conditions, the amount of accumulated uric acid is about 1200 mg in men and about 600 mg in women. The size of the urate pool is increased severalfold in individuals with gout. This excess accumulation may result from either overproduction or underexcretion. 

From the viewpoint of the microorganism, the art of fermentation represents an inefficient and wasteful process. Microorganisms have evolved over the years, developing better and better mechanisms to prevent overproduction of their metabolites. Yet we microbiologists... 

Feedback repression is the inhibition of formation of one or more enzymes in a pathway by a derivative of the end product. In many (but not all) amino acid biosynthetic pathways, the amino add end product must first combine with its transfer RNA (tRNA) before it can cause repression. Feedback repression is a widespread regulatory device especially for the synthesis of molecules intended for incorporation into macromolecules, e.g. amino adds, purines, and pyrimidines. Synthesis of vitamins also appears to be controlled by feedback repression, as well as by catabolite regulation (Birnbaum et al, 1967 Sasaki, 1965 Newell and Tucker, 1966 Wilson and Pardee, 1962 Papiska and Lichstein, 1968). Regulation of vitamin synthesis is important since only a small number (probably about 1000) of vitamin molecules are required per cell whereas many molecules of an average amino acid (probably 50 million) are required. An extremely wasteful case of vitamin overproduction would develop if enzymes for vitamin synthesis were produced at the same rate and were as active as the amino acid biosynthetic enzymes. 

The activation of ATCase by ATP occurs when metabolic energy is available for DNA replication and the synthesis of pyrimidine nucleotides. Feedback inhibition by CTP prevents the overproduction of pyrimidine nucleotides and the waste of precursors. 

The pursuit of perfection is a lean principle that engages the tools and thinking of continuous improvement to create value by eliminating wastes. Lean specifies nine deadly wastes as overproduction, transports, inventory, motions, waiting, over-processing, defects, knowledge and energy loss. These wastes are clearly related to sustainability competency. For example, consider environmental waste, as defined by the US-EPA (2007, p. 2) as... 

Seven wastes Shigeo Shingo developed these waste categories as part of the Just-in-Time philosophy overproduction, waiting, transportation, stocks, motion, defects, and processing. 

Unnecessary waste (spare parts, fabric, thread, etc.) Rework Overproduction Inappropriate processing... 

A Muda check takes place as a waste scavenger hunt to further minimize the possibilities of product defects, overproduction, excessive product handling, idle and waiting time by operating personnel, and excessive inventory and to improve efficiency in processing and encourage the best possible use of employee skills. All levels of personnel are involved. 

Transportation Station D represents the wastes deriving from the additional storage space and material handling needed because of overproduction at Station C. 

Waiting Although overproduction occurs at Station C, personnel at Station E often are not fully occupied, and waste occurs while they are waiting for other components to be delivered. Inventory controls are inadequate, and the motorized delivery system is inefficient and risky. 

Overproduction At Station C, the machinery processes parts faster than can be handled by the remainder of the production line. Thus, materials in progress get stacked in aisles until they are transferred to a storage area. Having excess materials in process is wasteful. An additional result is overly stressful manual material handling and the ergonomic risks that implies. 

Transportation Station D represents the wastes deriving from the additional storage space and material handling needed because of overproduction at Station C. The storage configuration is not conducive to efficiency. Aisles are narrow. Powered vehicles have collided, have struck workers, and goods have been damaged. 

Monazite is recovered mainly for its content of rare earth metals, and thorium has to be separated. This has led to an overproduction of thorium oxide. The excess is stored for potential use or disposed of as a radioactive waste. Most producers of rare earths have however switched to thorium-free raw materials due to the problems (and costs) of dealing with the radioactivity. This may change the situation for thorium supply. Other thorium minerals, besides monazite, are thorite ThSiO (Figure M24) and thorianite ThO. ... 

Waste of overproduction— reduced setup times, process synchronization, visibility... 

Seven wastes Taiichi Ohno s original catalog of the wastes commonly found in physical production. These are overproduction ahead of demand, waiting for the next processing stop, unnecessary transport of materials, overprocessing of parts due to poor tool and product design, inventories more than the absolute minimum, unnecessary movement by employees during the course of their work, and production of defective parts. 

Naturally-occurring and selection-induced resistance to analogues are two aspects of the same problem which concerns the protection mechanisms developed by cells against otherwise toxic agents. Metabolic adjustments may lead to an overproduction of the natural competitor. Analogues disrupt the control systems which operate by directing active metabolic assimilation (transport mechanisms) or by avoiding a wasteful metabolite oversynthesis, as well as excessive enzyme production. 

The waste of overproduction making or delivering too much, too early or just in case. Instead, the aim should be to make just-in-time - neither too early nor too late. Overproduction creates unevenness or lumpiness of material flow, which is bad for quality and productivity. It is often the biggest source of waste. 

What is meant by the term overproduction Why do you think this has been described as the biggest waste of all ... 

---