Product wastes

The major catabolic products that are toxic to isolated cells or those in tissues are ammonia [52] and lactate [53], the by-products of glutaminolysis [54] and glycolysis. Uniquely, glutamine has two amino groups and the ammonia arising from the degradation of the amino acid has adverse effects on intracellular 

Lactate is freely transported from the cytosol through the plasma membrane to the environment where it decreases the bulk phase pH. This is one of the reasons why a Mycoplasma infection, so dreaded by those who culture cells, is harmful to them. These organisms are glycolytic engines [10] and adhere to the cell surface, pumping out lactate in relatively large amounts. 

The cells in primary and secondary tumours as well as their descendants in culture have lost the mechanism causing contact inhibition. Thus, they continually grow and divide, overwhelming other tissues in vivo and forming multiple layers in culture dishes. Actively growing normal and cancerous cells have a higher metabolic activity than those that are in G, phase or have 

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A complex gathering station may include facilities to separate produced fluids, stabilise crude for storage, dehydrate and treat sales gas, and recover and fractionate NGLs. Such a plant would also handle the treatment of waste products for disposal. 

Uronic acids are biosynthetic intermediates m various metabolic processes ascorbic acid (vitamin C) for example is biosynthesized by way of glucuronic acid Many metabolic waste products are excreted m the urine as their glucuronate salts... 

The derivatives are hydroxyethyl and hydroxypropyl cellulose. AH four derivatives find numerous appHcations and there are other reactants that can be added to ceUulose, including the mixed addition of reactants lea ding to adducts of commercial significance. In the commercial production of mixed ethers there are economic factors to consider that include the efficiency of adduct additions (ca 40%), waste product disposal, and the method of product recovery and drying on a commercial scale. The products produced by equation 2 require heat and produce NaCl, a corrosive by-product, with each mole of adduct added. These products are produced by a paste process and require corrosion-resistant production units. The oxirane additions (eq. 3) are exothermic, and with the explosive nature of the oxiranes, require a dispersion diluent in their synthesis (see Cellulose ethers). 

Generally, for most fermentation processes to yield a good quality product at a competitive price, at least six key criteria must be met. (/) Fermentation is a capital intensive business and investment must be minimised. (2) The raw materials should be as cheap as possible. (J) Only the highest yielding strains should be used. (4) Recovery and purification should be as rapid and as simple as possible. (5) Automation should be employed to minimise labor usage. (6) The process must be designed to minimise waste production and efftciendy use all utilities (26,27). 

Pyrolysis of chlorodifluoromethane is a noncatalytic gas-phase reaction carried out in a flow reactor at atmospheric or sub atmospheric pressure yields can be as high as 95% at 590—900°C. The economics of monomer production is highly dependent on the yields of this process. A significant amount of hydrogen chloride waste product is generated during the formation of the carbon—fluorine bonds. 

Environmental Factors. The control, recovery, and disposal of mercury-bearing waste products are as important to the mercurials industry as the manufacturing process. The difficulties involved in removing mercury from waste-product streams and the problems of recovery or disposal have resulted in a substantial reduction in the number of manufacturers of mercury compounds as well as in the variety of mercury compounds being manufactured. Moreover, the manufacturing process used for a mercury compound may not necessarily be the most efficient or economical. Rather, the choice may depend on the nature of the by-products, the toxic hazard of the process, and the ease of recovery of the mercury from the waste-product stream. 

The function of the essential oil in the plant is not fully understood. Microscopic examination of plant parts that contain the oil sacs readily shows their presence. The odors of flowers are said to act as attractants for insects involved in pollination and thus may aid in preservation and natural selection. Essential oils are almost always bacteriostats and often bacteriocides. Many components of essential oils are chemically active and thus could participate readily in metaboHc reactions. They are sources of plant metaboHc energy, although some chemists have referred to them as waste products of plant metaboHsm. Exudates, which contain essential oils, eg, balsams and resins, act as protective seals against disease or parasites, prevent loss of sap, and are formed readily when the tree tmnks are damaged. 

There are three commercial routes to ADN in use. The first method, direct hydrocyanation of 1,3-butadiene [106-99-0] has replaced an older process, cyanation via reaction of sodium cyanide with 1,4-dichlorobutane [110-56-5] owing to the lower cost and fewer waste products of the new process. During the initial steps of the direct hydrocyanation process, a mixture of two isomers is generated, but the branched isomer is readily converted to the linear 3-pentenenitrile [4635-87-4]. 

Bulk sohds do not always discharge rehably. Unrehable flow, which can occur with some frequency, can be expensive in terms of inefficient processes, wasted product, and operational comphcations. Predictable flow is often impeded by the formation of an arch or rathole, or fine powders may flood uncontroUably. 

Bile Pigments. The oxidative degradation of heme yields open-chain tetrapyrrole as a waste product in humans and other higher animals. The yellow color of the skin in jaundice victims is caused by the presence of biluubin [635-65-4] (32, R = (CH2)2COOH). 

Essentially no waste products are formed ia the USP process if hydriodic acid and either sodium hydroxide or sodium carbonate are used as reactants. Water results from use of the former a mole equivalent quantity of carbon dioxide is produced from the latter reagents. Higher quaUty grades may require some purification steps which may result ia wastes from the treatment. Disposal of these impurities must then be carried out. 

The manufacture of sugar was early understood to be an energy-intensive process. Cuba was essentially deforested to obtain the wood that fueled the evaporation of water from the cane juice. When the forests were gone, the bagasse burner was developed to use the dry cane pulp, called bagasse, for fuel. Bagasse was no longer a waste product its minimal value is the cost of its replacement as fuel. 

Sulfur is unusual compared to most large mineral commodities in that the largest portion of sulfur is used as a chemical reagent rather than as a component of a finished product. Its predominant use as a process chemical generally requires that it first be converted to an intermediate chemical product prior to use in industry. In most of the ensuing chemical reactions between these sulfur-containing intermediate products and other minerals and chemicals, the sulfur values are not retained. Rather, the sulfur values are most often discarded as a component of the waste product. 

Paints. Paints account for perhaps 3% of sulfur consumption (see Paint). The main sulfur use is for the production of titanium dioxide pigment by the sulfate process. Sulfuric acid reacts with ilmenite or titanium slag and the sulfur remains as a ferrous sulfate waste product. Difficulties with this process have led to the development of the chloride process (see Pigments, inorganic Titanium compounds). 

Modifications and improvements to the basic process have been made to reduce the quantity of waste products (21,22) in the wet chemical process, to recover HF, and to economically process low Ta, high Nb containing raw materials (23). Several alternative extraction media have been reported in the hterature. Most, except for tributylphosphate (TBP) (24) and tri- -octylphosphine oxide (TOPO) (25), have never been used in industry. 

Recycling. Beryllium is typicaUy recycled, thus it is not a waste disposal problem in fact, it is rarely a waste product at aU. Because of the high cost of producing beryUium, beryUium producers repurchase clean scrap from customers for recycling and reuse. 

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