Microbiological Deterioration Research Articles

An Approach to the Kinetics of Microbiological Deterioration

An Approach to the Kinetics of Microbiological Deterioration

Microbiological Deterioration Of Buried Pipe and Cable Coatings

Abstract Visual tests of nutrient inertness on 28 coating materials showed that only half were inherently inert to the attack of four selected species of fungi. One of the materials had fungistatic properties. The visual tests were useful for screening materials for more extensive testing Tensile tests of coatings buried in soil showed that polyethylene and polyvinyl chloride were immune to deterioration, that a neoprene coating was infested with fungi and that a tar-imprognated cotton fabric was deteriorated to a marked extent in inoculated soil. By the use of “sterilized” soil, the influence of the physical and chemical properties of the soil on coatings can be separated in part from the action due to soil micro-organisms. Insulation resistance measurements on coated pipes and cables buried in soil boxes gave sensitive indication of coating changes. Because of difficulty in maintaining a soil “sterile” it is not possible to separate the effects of moisture absorption and microbiological deterioration in...

Microbiological deterioration of vulcanized rubber.

Data are presented which show that the constitution of the recovery medium exerts an appreciable effect on the apparent thermal resistance of spores of Putrefactive Anaerobe 3679. The routine use of a simple yeast extract-starch medium (YES) as a recovery medium in thermal resistance studies on this organism is recommended. In addition to giving thermal resistance values comparable to those obtained in Yesair's pork infusion, it has the advantages of ease of production, reduced cost, and a standardized method of preparation.

Microbiological Deterioration of Vulcanized Rubber

Data are presented which show that the constitution of the recovery medium exerts an appreciable effect on the apparent thermal resistance of spores of Putrefactive Anaerobe 3679. The routine use of a simple yeast extract-starch medium (YES) as a recovery medium in thermal resistance studies on this organism is recommended. In addition to giving thermal resistance values comparable to those obtained in Yesair's pork infusion, it has the advantages of ease of production, reduced cost, and a standardized method of preparation.

The Microbiological Deterioration of Rubber Insulation

The Microbiological Deterioration of Rubber Insulation

The Microbiological Deterioration of Rubber Insulation

The Microbiological Deterioration of Rubber Insulation

The Microbiological Deterioration of Rubber Insulation

Abstract Experiments on natural rubber and GR-S insulation in various forms have shown them to be inherently vulnerable to fungus attack unless made sufficiently fungitoxic. Stable fungitoxic GR-S compounds have been developed in this work which have invariably maintained normal high insulation resistance during four years in active soil. Thin Neoprene jackets may be permeable to fungi so that underlying insulation should be fungitoxic or inherently stable. A humid atmosphere as in a wet duct may be a dangerous environment. It has been shown that inoculated wire can fail in moist air due to fungus penetration. Parallel electrical tests on wire and culture tests on agar-filled tubes demonstrated that the electrical failures in soil were caused by fungus penetration. It was possible to detect and identify fungus in transit in thick walls of GR-S insulation. Three types of fungi which can pass through rubber insulation and thin Neoprene jackets have been identified, at least by genus. The most prevalent has been Spicaria violacea Abbott. The presence of fungus in insulation lowers the dielectric strength before the filaments have passed completely through the wall. Impending failure can be detected by voltage breakdown tests. Rubber insulation in buried cables must be sufficiently fungitoxic. Great care is required in formulating stable compounds to insure that other required properties are not harmed.

The Microbiological Deterioration of Rubber Insulation [includes discussion

RESEARCH DEVOTED to developing rubber insulations resistant to micro-organisms has given two major results: 1. Compounds showing normal insulation resistance with no failures after 4 years in accelerated soil tests in which ordinary compounds fail in about 6 months; 2. Proof that the destructive organisms are fungi, and that these cause loss of insulation resistance and dielectric strength by growing through the insulation.

網糸の腐蝕に関する微生物学的研究-III

The microbiological deterioration of fishing nets during storage was preliminarily studied. 1) After periods of from three to six months' storage under dry conditions, textile fibres of fishing nets were found to be covered with a large number of survived cells of aerobic cellulose-decomposing bacteria of marine origin. These findings suggest an important role played by marine cellulose-decomposing bacteria in deterioration of textile fibres during storage. 2) Fourteen strains of marine aerobic cellulose-decomposing bacteria were purely isolated from the fishing nets which had been stored, under dry conditions, for three months after fishing. These isolated bacteria were classified into a new species of myxobacteria, viz., Cytophaga haloflava after detailed taxonomical studies.

Chemical Substitution in Fibrous Cotton and Resistance of Substituted Cotton to Microbiological Deterioration

The resistance for months to deterioration by microorganisms (in soil burial) of suitably acetylated fibrous cottons, some with only one-third of the hydroxyl groups substituted, depends upon the distribution of the acetyl groups as well as upon the total number of such groups present. Under usual conditions of acetylation, according to the literature, reaction takes place first in the amorphous cellulose, starting at the most accessible places. According to the present ex perimental acetylations and special dyeing tests, the reaction, which is probably confined at first to the amorphous cellulose, takes place along fibers in various segments and throughout cross sections rather than as a layer increasing in thickness from the surface inward. At one-third substitution the amorphous cellulose is converted to triacetate; the cotton fiber still contains about two-thirds of the original cellulose, which is present as crystalline material surrounded by acetylated cellulose. The swelling capacity of the cotton in water is greatly reduced. While the mode of attack by microorganisms is not completely understood, they apparently begin at the most readily accessible amorphous cellulose. From the literature and from the present experiments, protection by partial acetylation is believed to be due to the blocking of hydroxyl groups, the filling of spaces between chains in the amorphous cellulose, and the sup pression of swelling. It represents a general method of rendering cellulose unsuitable, or at least inaccessible, as a food for microorganisms. A relatively low degree of partial saponification may detract greatly from the rot-resistance of a well-protected acetylated cotton owing to the restoration of amorphous cellulose, with loss of blocking groups and a restoration of swelling capacity. Partial methylenation by treatment with formaldehyde may impart a moderate degree of rot-resistance, which seems best explained as being due to the suppression of swelling by cross linking. Formaldehyde-containing resins which impart rot-resistance apparently act similarly. The evidence obtained indicates that the amorphous cellulose is the part which is normally attacked, and that its ability to swell in water may be a more important factor in microbiological attack than is commonly recognized. The use of dyeing has been exemplified for qualitative tests to supplement other evidence regarding substitution and the composition and properties of substituted cottons.

Microbiological deterioration of manufactured materials.

s, 43, 3181g (1949) 67. Pady, S. M. , Kelly, C. D., and Polunin, N., Nature, 162, 379-81 (1948) 68. Properties of Chemical Engineering Materials of Construction, Ind. Eng. Chern., 42, 2026-76 (1950) 69. Reese, E. T., Levinson, H. S., Downing, :\1 . H., and White, W. L., Farlowia, 4(1), 45-86 (1950) 70. Reese, E. T., Siu, R. G. H., and Levinson, H. S., J. Bact., 59, 485-97 (1950) 71 . Reynolds, E. S. , Mycologia, 42, 432-48 ( 1950) 72. Rogers, T. H., J. Inst. Metals, 75, 19-38 (1948) 73. Rosenfeld, W. D., J. Bact., 54, 664-65 (1947) 74. Sachs, N., Deterioration of Marine Corps Field Shoes in Storage, 58 pp. (U. S. Marine Corps Depot of Supplies, Philadelphia, Pa., Rept. No. 02, 195 1) 75. Salvin, S. B., Ind. Eng. Chern., 36, 336-40 (1944) 76. Sanborn, J. R., and Gillotte, R. A., Paper Trade J., 1 12(21) , 33-37 (1941) 77. Sen Gupta, S. R., Nigam, S. S., and Tandan, R. N., Textile Research J., 20, 671-

Microbiological Deterioration of Cellulose During the First 72 Hours of Attack

Microbiological Deterioration of Cellulose During the First 72 Hours of Attack