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Previously published methods for the solution of one-dimensional heat-conduction problems with melting or freezing are briefly reviewed and weaknesses of previous analytic and numerical methods are outlined. Two new and more generally applicable numerical methods, applicable to digital and analog computation, are developed in the paper. Sample problems using these new techniques are solved and compared with the results of a widely used conventional method. An evaluation of the various methods and recommendations on areas of application are included.

The low substrate specificity of alcohol oxidase from Pichia pastoris makes this enzyme system of potential biotechnological interest. Whole cells of Pichia pastoris are able to oxidize benzyl alcohol to benzaldehyde in aqueous reaction media. The low water solubility of the reactant and product of this bioconversion, combined with the ability of both to strongly inhibit the reaction, favor the use of nonaqueous reaction fluids. Purified alcohol oxidase was shown to function in a number of 2-phase reaction systems of varied aqueous to organic phase ratios (0.01-0.05 v/v). The apparent V(max) and K(m) were 5.26 g/Lh and 7.41 g/L respectively, for the oxidation of benzyl alcohol to benzaldehyde in hexane containing 3% aqueous phase. The volume of the aqueous phase had a strong effect on the reaction, with an aqueous: organic ratio of 3-5% found to be optimum. The enzyme could be firmly immobilized on DEAE-Biogel (Biorad) to enhance stability and biocatalyst recovery.

A new species of Clostvidium isolated from a methanogenic cellulose-enrichment culture of sewage sludge is described. The colonies produced by these bacteria were white, circular, and convex with smooth margins. The cells were straight, spindle-shaped rods, 0.6 by 3.0 pm in size. They were gram negative and nonmotile, and they formed round, terminal spores. A wide variety of carbohydrates was fermented by this mesophilic anaerobe. The major fermentation products were acetic acid, hydrogen, carbon dioxide, and ethanol. The deoxyribonucleic acid base composition was 28 mol% guanine plus cytosine. The name Clostridiurn saccharolyticurn is proposed for this new species on the basis of its broad saccharolytic activity. The type strain of C. sczc.c.hLrrol\/ticirrn is WM1 ( = . . NRC 2533).A new species belonging to the genus Clostridiurn was isolated during the course of a study of the digestion of cellulose by a highly cellulolytic mixed culture. This culture was obtained from a methanogenic cellulose-enrichment culture started from sewage sludge (4, 5). In the present paper we define the characteristics of and propose a name for this newly discovered microorganism. MATERIALS AND METHODS Media.The basal medium used for the isolation and maintenance of the new isolate was the synthetic saltvitamin medium previously described by Khan et al. (6). The basal medium was supplemented with 0.1% yeast extract and was prepared by the procedure of Holdeman and Moore (1). The pH of the medium was adjusted to 7.2 to 7.4 prior to being reduced by the Hungate technique (2). For the preparation of media containing insoluble substrates, such as cellulose, the reduced medium was dispensed, under 80% N?-20% C 0 2 , in 10-ml volumes into 60-ml serum vials containing preweighed amounts of the substrate and was then autoclaved. Soluble substrates were filter sterilized and were injected by hypodermic syringe into the basal medium after the vials had been autoclaved and cooled. The isolated microorganism was maintained in basal medium supplemented with 2% (wthol) cellobiose and 0.1% yeast extract (YE).Isolation. A methanogenic cellulose-enrichment culture described by Khan (4) was used as the source of inoculum for isolation purposes. The inoculum was heated at 90°C for 15 min and was then serially diluted in basal medium. Prereduced cellobiose-agar slants, inside 160-ml serum vials, supplemented with 0.1% (wthol) YE, were spread with a 0.1-ml quantity of i. Issued as NRCC no. 19895. each dilution. The inoculated agar slants were flushed with an 80% N2-20% C 0 2 gas mixture, sealed, and incubated at 35°C. After 48 h, an individual colony was picked and transferred to cellobiose-YE broth. The broth was heated at 90°C for 15 min, serially diluted, and replated on cellobiose-YE agar. This procedure was repeated a total of five times.Biochemical tests. Biochemical tests were carried out in basal medium containing 0.1% YE and 2% of the selected substrate, by the procedures of Holdeman and Moore (1). The inoculated test vials were incubated at ...