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The decrease in tensile strength of chemically untreated cotton threads that had been exposed at different levels in lake water and lake sediment was investigated. The quotient of the tensile strength before and after exposure was taken as a measure of the potential cellulolytic activity. Two oligotrophic Swedish lakes showed a very weak cellulolytic activity. In the eutrophicated Lake Trummen the activity was high in the summer specially at the sediment-water interface, but low in the winter. During the restoration of this lake by suctiondredging the nutrient-rich sediment up on land, an easily measureable activity could also be detected in the water. The cellulose degradation was also studied in some rivers and streams and in the water of three sewage treatment plants.

Um die Kinetik des oxidativen Abbaus nativer Cellulose viskosimetrisch verfolgen zu konnen, mussen neue [η]-M-Eichbeziehungen aufgestellt werden, da die Behandlung der Cellulose mit konzentriertem Alkali den Staudingerindex [η] erniedrigt, ohne das Molekulargewicht M zu verandern. Es wurden zwei Reihen oxidativ abgebauter, verschieden lange mit Alkali vorbehandelter Cellulosen hergestellt und an diesen die Konstanten der Kuhn-Mark-Houwink-Gleichung fur die Cellulosenitrate in Aceton und die Cellulosen in Cuoxam (Cu(NH3)4(OH)2) durch Vergleich mit Lichtstreuungsmessungen bestimmt. For kinetic studies of cellulose degradation by molecular oxygen it is necessary to establish new [η]-M-relationships, since the treatment of cellulose by concentrated alkali solutions changes the intrinsic viscosity [η] without changing the molecular weight M. Two series of degradated celluloses treated for different times with sodium hydroxide solutions were prepared, and the constants of the Kuhn-Mark-Houwink equation were determined for cellulose nitrates in acetone and for celluloses in Cuoxam (Cu(NH3)4(OH)2) by comparison of intrinsic viscosity with light scattering data.

A study was made of the alcoholysis of cotton linters using methanol, n-butanol, n-hexanol, and n-octanol acidified with hydrogen chloride. All traces of water could not be removed from this system, and further water was formed during the degradations by a reaction between the alcohol and the hydrogen chloride. The linters were degraded in all of the alcohols studied. The amount of linters solubilized during the degradations tended to increase as the molecular weight of the alcohol used increased. It appeared that, in the study made, the cellulose was being degraded by hydrolysis caused by the traces of water present. The acidified alcohols combined with the reducing groups formed to give a degraded cellulose with a low reducing value. The residual reducing power was lowest when methanol was used.

It has been shown theoretically that the quasiperiodical distribution of unordered regions along cellulose microfibrils does not significantly affect the molecular weight distribution which arises from heterogeneous reactions of cellulose involving a limited number of acts of chain rupture.

A comparison of the DP distributions of wood pulps and the cellulose acetates prepared from them shows that the DP distributions of the acetates are essentially exponential and virtually independent of the DP distribution of the original pulp. The DP of a number of acetates prepared under identical conditions from different pulps were unrelated to the DP to the starting pulps. Although the pulp DP is thus not a factor which determines the acetate DP, there are other intrinsic properties of the pulp which do affect the final DP of the cellulose acetate. The nature of these properties is not understood, but it can be shown that they are altered by changes in wood pulp processing. The ratio of hemicellulose in pulp to hemicellulose in the acetate made from it varies from one pulp to another. The acetate solution properties of the cellulose are more closely related to the composition of the acetate flake than to the composition of the original pulp. The viscosity of the concentrated acetate dope can be accounted for almost entirely in terms of flake DP and flake mannan content. Pulp manufacturers and acetate producers should strive toward conditions which increase the rate of degradation of the he mi celluloses and decrease the rate of cellulose degradation during acetylation.

Gravimetric analyses of cellulose (Solka Floc) utilization by representative marine Ascomycetes, including Lulworthia floridana, Lindra sp., Torpedospora sp. and Halosphaeria mediosetigera, have shown noteworthy activity based on loss of weight of cellulose by the various fungi. Particularly striking activity is evidenced by L. floridana and Torpedospora sp., with >50% cellulose degradation after 3 weeks of fungal growth. Comparable studies with the deuteromycete, Dendryphiella salina, showed >50% loss within 6 days. Dissimilar responses by various L. floridana isolates are noted. Intensive degradative activity at pH's of 6 to 8 is common along with negligible amounts of cellulase (Cx units). Adsorption of the enzyme to the mycelia or to the cellulose particles in the medium is suggested. Earlier laboratory analyses of fungal degradation of Manila cordage compare favorably with present gravimetric studies and support field observations on the significance of fungal infestation of wood, particularly that incited by the Lulworthia floridana group.

The molecular weight distribution in various celluloses degraded with hydrochloric acid has been studied by gel-permeation chromatography. Measurements were made on the residue after hydrolysis, on the degradation products solubilized by the acid, and on whole degraded samples comprising the product soluble in the acid plus the residue. It is shown that the total number of crystallites decreases during hydrolysis while the chain length distribution remains constant. The crystallites are gradually broken down into molecular fragments which show a size distribution centered on species with a degree of polymerization of about 8. Possible interpretations of these results are discussed.