Kazutoshi Yoshihara

Pretreatment of pectic wastewater from orange canning process by an alkalophilic Bacillus sp.

Abstract An alkalophilic bacteria that secretes endo-pectate lyase was isolated from soil in Thailand and identified as a Bacillus sp. The strain, designated as GIR 621, was applied to the pretreatment for more effective activated-sludge treatment of pectic wastewater from orange-canning factories. The bacterial pretreatment decreased the uronic acid of the wastewater by 91%, when supplemented with Polypepton, yeast extract, soybean powder, phosphorus and potassium (pH 10.0) for 36 h. The strain did not grow on simple synthetic media or under nonalkaline conditions, so the use of the potential phytopathogen should not involve biohazards.

Purification and properties of a chitosanase from Pseudomonas sp. H-14

Purification and Properties of a Chitosanase from Pseudomonas sp. H-14 Kazutoshi Yoshihara, Jun Hosokawa, Takamasa Kubo, Masashi Nishiyama & Yojiro Koba To cite this article: Kazutoshi Yoshihara, Jun Hosokawa, Takamasa Kubo, Masashi Nishiyama & Yojiro Koba (1992) Purification and Properties of a Chitosanase from Pseudomonas sp. H-14, Bioscience, Biotechnology, and Biochemistry, 56:6, 972-973, DOI: 10.1271/bbb.56.972 To link to this article: http://dx.doi.org/10.1271/bbb.56.972

New application of cellulose and chitosan for biodegradable polymer material

We found that a combination of fine cellulose and chitosan was suitable for forming biodegradable films and moldings. The composite film demonstrated high strength and had a maximum wet strength at 10-20% chitosan content. Besides the major hydrogen bonding between chitosan and cellulose, the amino groups in chitosan and the trace amounts of carbonyl groups in cellulose played an important role in the formation of the composite. This film was completely decomposed by microorganisms in soil or sea water. The biodegradability was controlled by adjusting the temperature in heat treatment, the quantity of carbonyl group in the cellulose, etc. We have also been working on joint research with companies to produce films, nonwoven fabrics and foams. Foams and nonwoven fabrics of the composite were found to be effective in healing of skin defects of rats. We are also trying to produce fine cellulose material for the biodegradable plastic by simple and convenient method grinding together with an organic solvent. The production of chitosan by cultivation of a fungus such as Rhizopus acetoinus is also discussed.

Biodegradable plastics derived from micro-fibrillated cellulose fiber and chitosan

We have been carrying out studies to develop biodegradable plastics from natural polysaccharides. We have found that a combination of micro-fibrillated cellulose fiber and chitosan produces a useful material that can be used to form biodegradable film and moldings. Cellulose-chitosan composite film demonstrate higher strength than general purpose plastic films, and wet strength peaks when chitosan content is 10-20%. The relatively small amount of chitosan needed is economically convenient because chitosan is more expensive than cellulose. This film biodegrade well in soil, completely dissolving and disappearing in two months. Biodegradability is influenced by the temperature used in thermal treatment the film, the quantity of acid groups in the cellulose, and other factors. These characteristics will be used to control decomposition. Since cellulose-chitosan plastics are not thermoplastics, we have been working on joint research with companies to produce films, nonwoven fabrics and foams. We discuss here the properties and application of these composite moldings.

Hydrolysis of Xylan Fragments in Solvolysis Pulping Waste Liquor by Cation-exchange Resin

Solvolysis pulping (hardwood) yj^ hydrolysis of xylan fragments contained in the water-layer waste liquor of solvolysis pulping was invesYvlan tigated by using solid-acids, such äs conventional sulfonated styrenedivinylbenzene resins and a perfluorinated sulfonic resin.The solvolysis pulping process comprises a cooking of beech chips with cresol-water (8:2) liquor; xylan fragments are dissolved äs predominant hemicellulose components into the water-layer after cooking. In Order to obtain xylose from the water-layer, it is necessary to hydrolyze xylan fragments in the water-layer. Among three resins» a porous-type sulfonated styrenedivinylbenzene resin was chosen for use in the hydrolysis. The optimum conditions for the hydrolysis were heating the water-layer with the resin at 150°C for 40 min. The degree of hydrolysis with 50 g resin L-water-layer reached ca. 90% of that with sulfuric acid. Cresol of up to 10% concentration in the water-layer did not exert any unfavourable effect on the hydrolysis. The cation-exchange capacity of the resin became low only by about 20% after heating at 150°C for 12 hrs. Xylan Hydrolysis Acidolysis Cation-exchange resin Xylose Beechwood