Solubilization of cotton

In 1971 and 1972 Halliwell and co-workers (21, 57) separated the T. viride cellulase into four fractions—Ci, C2, CM-cellulase, and cello-biase. It was suggested that the Ci enzyme was a cellobiohydrolase since the principal product of its action was cellobiose. Addition of cellobiase with the Cl enzyme permitted 70% solubilization of cotton after 21 days. No evidence of the enzyme purity was presented. 

Certain cellulolytic fungi yield cell-free filtrates capable of extensive degradation of highly ordered forms of cellu-losic material. These filtrates have been shoum to contain a so-called Cj-component, which, although essential for this type of activity, is virtually without action when freed from the other (Cx) components. Crcomponents, with very similar properties, have been isolated from Trichoderma viride and from Penicillium funiculosum. The powerful synergistic action on cotton previously found between the Ct and Cx components of T. viride was also displayed by those from P. funiculosum cross-synergism has also been demonstrated. An attempt has been made to explain the role of Ct in the solubilization of cotton. 

The Ci, Cx concept has recently been extensively studied by a number of workers (16,23, 24, 27, 31, 32,46), for two species of Trichoderma, namely T. viride and T. koningi. It was shown that cell-free culture solutions of these fungi were able to solubilize cotton fibers. The solubilization of cotton fibers is also a way of measuring the activity of the Ci enzyme. In the most recent of these publications (46) Selby and Maitland were able to isolate the Ci enzyme from culture filtrates of T. viride. The enzyme was shown not to act upon cellobiose or carboxymethyl cellulose and to lose its ability to solubilize cotton in the absence of the Cx component. The mechanism of action of the Ci enzyme is thus still obscure although many different hypotheses have been presented (34). 

Table X. Solubilization of Dewaxed Cotton by Reconstituted Mixtures of the Components of the Cellulase Complex of T. koningiia...

Kleman-Leyer, K. M., Siika-Aho, M., Teeri, T. T., and Kirk, T. K. 1996. The Cellulases Endoglucanase I and Cellobiohydrolase II of Trichoderma Reesei act synergistically to solubilize native cotton cellulose but not to decrease its moleculare size. Appl. Environ. Microbiol., 62,2883-2887. 

Preparations said to contain Ci from culture filtrates of either T, koningii or F. solani, when added to culture filtrates of various pseudo-cellulolytic organisms, were able to confer the capacity for extensive solubilization of dewaxed cotton fibers 41), Thus the purification of Cl factors and elucidation of their function have concerned several laboratories during the past few years. 

In addition, as the wash temperature decreases, the chain length of the hydro-phobic group for optimum oily soil removal appears to decrease. Thus, for oily soil removal from polyester/cotton by blends of homogeneous 3EO and 8EO nonionics having similar cloud points, the order of maximum oil removal at 70° was Ci4 = Ci2>Cio, at 38°C it was Cio = Ci2>Ci4, and at 24°C it was Ci0> Cn > C 14. The difference has been ascribed to the rate of solubilization of the soil, since the rate for these surfactant blends decreases with increase in the length of the hydrophobe (Benson, 1982). 

K. Selby The attack of mineral acid on cotton does not always follow the same course—i.e.9 a rapid solubilization of the first 10%). Jeffries, Roberts, and Robinson (1) have recently shown that the size of the rapidly hydrolyzed fraction varies with acid concentration and deduce that two clearly defined fractions are not present in the structure but that reaction is at an accessible surface, the accessibility depending on the concentration of the hydrolyzing acid. ... 

Three British chemists discovered that cellulose could be solubilized when it was treated with sodium hydroxide and carbon disulfide. The product is called cellulose xanthate. The viscous solution was then extruded through a nozzle into an acidic solution, forming Instrons, silk-like fibers. They patented the process and commercialized the prodnct in 1894. This is rayon. It is chemically still cellulose, but its texture is different from that of cotton. It can be produced from not only from cotton, but also from any pulp. 

All the enzymes considered so far aim at solubilizing the soils by degrading their main constituents. Cellulase, the last detergent enzyme type introduced on the market, plays quite differently and delivers other diverse benefits fabric softening, color brightening, antipilling, soil-release properties, and antiredeposition [31]. These benefits are the result of the removal of microfibrils from the surfaces of cotton fibers [5]. The efifects are cumulative and increase considerably with the number of wash cycles performed [2]. 

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