SEPTEMBER 1956
I/EC Briefs The why, what, and significance articles in this issue.
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Eng. C h e m . 48, 1383 (1956)
URETHANE PLASTICS—POLYMERS
PURIFYING CHEMICALLY POLLUTED WATERS
A Staff Report
Ind.
In one decade polyurethanes have found great commer cial application in flexible and rigid foams, coatings, adhesives, and other products. Rigid, foamed-in-place urethanes are accounting for an ever-increasing share of the foam market, with one company expecting at least 50% of urethane foam production in 1960 to be foamed-in-place. Urethane-based protective coatings should find significant use in the United States as formulation variations and applications are developed. In Europe, both protective and electrical insulating urethane coatings have been widely used. Urethane rubber and molding compounds are receiving industry attention. Costs of different urethane systems are discussed, together with comparisons of foamed urethanes, rubber, and vinyl. Raw material suppliers, finished foam producers, specific markets, and future trends are presented.
Microbial Adaptation Modification of its environment is met by the microbe in three ways: The microbe yields the environment to occupancy by an other species Better adjusted mutants within the culture gain ascend ancy over their fellows Modification within the individuals permit them to cope with the environmental change An understanding of these processes of adaptation is de sirable when microorganisms are to be used as reagents in an industrial process. ORVILLE WYSS University of Texas, A u s t i n , Tex
Ind. Ind.
Eng. C h e m . 48, 1407 (1956)
Eng. C h e m . 48, 1392 (1956)
Statistical Method for Chemical Engineers Statistics can make a real contribution to chemical engi neering in giving engineers a means of measuring the random variability of their processes, together with a means of partitioning the variability into parts allocable to different sources. Few chemical engineers are familiar with the advantages of the major statistical devices which can be used. This article shows the fundamentals of these methods, what they can do, and how to use them. CUTHBERT DANIEL 116 Pinehurst Ave. New Y o r k 33, Ν . Υ .
Eng. C h e m . 48, 1404 (1956)
Microbial Associations and Antagonisms Microbial interrelations play a very important role in soils and in water. This is generally recognized. But most of the microbial interactions in nature are so complex that investigations have rarely attained comprehensive scope in analysis, not to mention synthesis, of associative phenomena. A discussion is given here of some principles and examples, considering (1) techniques, (2) types of microbial interrelations, (3) use of laboratory models, and (4) the role of antibiotics in nature. R. W E I N D L I N G Lederle Laboratories, A m e r i c a n C y a n a m i d C o . , Pearl River, Ν . Υ .
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Eng. Chem. 48, 1411 (1956)
Transformations of Carbon Compounds by Microorganisms From the large body of knowledge available on the subject of carbon transformations by microorganisms, a variety of typical reactions have been selected for discussion. The reactions are considered under two headings—exocellular and intracellular transformations. Under the former are included decomposition of cellulose, chitin, and keratin and oxidative degradation of aromatic substances such as lignin, guayule resins, and herbicides. The development by microorganisms of adaptive enzymatic equipment to handle synthetic polymers is briefly considered. Some theoretical considerations on consecutive levels of enzymatic depolymerization are developed, and the uptake of solubilized materials by the cell is touched on. Under intracellular transformations some dissimilative reactions involved in fermentation and oxidative metabolism are dealt with. A few assimilative steps for converting carbon compounds into cellular substance are mentioned. WALTER J . NICKERSON Rutgers University, New Brunswick, N. J .
Ind.
Eng. Chem. 48, 1438 (1956)
Biological Formation of Methane Methane is formed by a group of highly specialized obligately anaerobic bacteria from a variety of organic and inorganic substrates. Only a few of these bacteria have as yet been isolated in pure culture. The organic compounds usually fermented are products of other bacterial fermentations, such as fatty acids, alcohols, and ketones. Methaneproducing bacteria are not known to attack carbohydrates, amino acids, or their polymers. Some bacteria form methane entirely from carbon dioxide, which is used as a major oxidizing agent. Other bacteria also form methane from acetate or methanol by reactions not involving carbon dioxide as an intermediate. Little is known about the biochemical mechanisms of methane formation. H. A. BARKER University of California, Berkeley, Calif.
Ind.
Eng. Chem. 48, 1444 (1956)
Microbial Decomposition of Hydrocarbons Ind.
Eng. Chem. 48, 1421 (1956)
Biological Transformation of Nitrogen Compounds Biological transformations of ammonia, amino acids, and other nitrogenous compounds are reviewed with regard to over-all mechanisms and with particular reference to the relationship to the problems of process waste waters. The phenomena of nitrification and denitrification in this regard are also discussed as they relate to the problems of nitrogen disposal. C. C DELWICHE Kearney Foundation of Soil Science, University of California, Berkeley, Calif.
The utilization of gaseous hydrocarbons by soil microorganisms is being studied in the United States and in the U.S.S.R. principally from the standpoint of detecting indirectly petroleum gas emanations in prospective areas. Products formed from the microbial decomposition of natural gas have not been exhaustively investigated, nor has the formation of products from higher hydrocarbons. Biological disposal of refinery wastes is only just beginning. The mechanism of hydrocarbon oxidation also has not been adequately examined. The methodology for such investigations is no different than is used for studies of carbohydrate or organic acid metabolism and should yield accordingly to research. Fortunately, academic interest is currently being shown in this virtually unexplored field of microbial metabolism. J. B. DAVIS Magnolia Petroleum Co., Dallas, Tex.
Ind.
Ind.
Eng. Chem. 48, 1429 (1956)
Eng. Chem. 48, 1449 (1956)
Transformations of Sulfur by Microorganisms
Photosynthesis in the Algae
Microorganisms oxidize and reduce elemental sulfur and various inorganic and organic sulfur compounds with formation of diverse products. The most common end products in aerobic and anaerobic environments are sulfate and sulfide, respectively, but elemental sulfur sometimes accumulates under anaerobic conditions. Certain autotrophic bacteria utilize sulfur and reduced inorganic compounds as sources of energy for growth, whereas for others sulfate serves as an oxidizing agent for anaerobic development. Sulfur transformations by microorganisms lead to the formation of geological deposits of sulfur and sulfides, to corrosion of iron and destruction of concrete, and to accumulation of acid in mine waters and soils.
Consideration of the role that algae may play in water purification requires basic understanding of the biology of the organisms and familiarity with the chemistry of the photosynthetic process. Data concerning the energy requirements, efficiency, and biochemical pathways in the photosynthetic mechanism, though often conflicting, have made some understanding of the process possible. Studies of the environmental requisites for maximum growth and photosynthesis have made possible predictions of the rates of uptake of raw materials and of the yields to be expected of the synthetic mechanism in the algae. Those topics which are of particular importance to engineers interested in exploiting this synthetic system are reviewed and discussed.
ROBERT L. STARKEY New Jersey Agricultural Experiment Station, New Brunswick, N. J .
ROBERT W. KRAUSS University of Maryland, College Park, M d .
VOL. 48, NO. 9 · S E P T E M B E R 1956
107 A
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