Masaru Ishihara

Characterization of native crystalline cellulose in the cell walls of Oomycota

Abstract Cellulose samples from 4 Oomycetes species ( Saprolegnia parasitica , Pythium aphanidermatum , Pythium butleri and Phytophtora cactorum ) have been investigated. They were purified by mild hydrolysis of the cell walls, followed by extraction in diluted NaOH. The β-(1–3) glucan, the main component of the hyphal cell wall, was then easily extracted. The purified cellulose was characterized by X-ray diffractometry, FT-IR, and electron microscopy. Both X-ray and electron diffratograms were poorly resolved and were similar to those of cellulose IV I . In addition, the observation of their cell walls revealed a microfibrillar network, the individual microfibril was, however, extremely narrow in width. Although the interpretation of their structure still remains uncertain because of the low crystalline nature, the detailed d-spacing analysis and the FT-IR inspection suggested that Oomycota cellulose could be either interpreted as cellulose IV 1 or low crystalline cellulose I β . The latter is favored from the taxonomic point of view.

Enzymatic Acyl Exchange of Triglyceride in n-Hexane

Chemical interesterification has been used to improve the physical properties of triglyceride in the oil and fat industry. In chemical interesterification, it is difficult to introduce the desired acyl group into the. desired position of glycerol because the reaction occurs randomly. On the other hand, it is well known that lipases (EC 3.1.1.3) show specificities toward the position of glycerol and the kind of acyl residue in hydrolysis!) and synthesis ) of triglyceride. So the acyl exchange reaction between triglyceride and free fatty acid using lipase seems to be useful for improving the properties of triglyceride. However, little investigation has been attempted up to now. ) In this paper, we describe a unique acyl exchange reaction in n-hexane using lipase dissolved in glycerol. Reactions were carried out in 200 ml rubber-stoppered vessels which contained, typically, 10 g olive oil, 10 g stearic acid, 40 ml n-hexane, and 40 mg lipase derived from Rhizopus delemar (200 units/mg solid, purchased from Seikagaku Kogyo Co. Ltd., and used for experiments without further purification. One unit activity was defined as that liberating 1 micromole equivalent of fatty acid from olive oil per minute.) in the presence of 0.1 ml glycerol or 0.3 M TES bubber (pH 6.5). The vessel was shaken for 1 to 3 days on a

Mycophenolic acid production by drug-resistant and methionine or glutamic-acid requiring mutants of Penicillium brevicompactum.

Penicillium brevicompactum ATCC 16024 produced 1.7 g/1 of mycophenolic acid (MPA) in the culture medium. Various drug-resistant mutants, showing resistance to such as polyene antibiotics, chemotherapeutic agents, redox indicator and surfactants, were derived from the fungus. Most of the mutants produced 2.0 ~2.5 g/1 of MPA. A clofibrate and dodecyltrimethylammonium chloride double resistant mutant, No. 4–23–11, produced 4.7 g/1 of MPA. A monofluoroacetic acid resistant strain, No. 5–1, derived from No. 4–23–11 produced 5.3 g/1 of MPA.A methionine auxotroph, M-l, derived from ATCC 16024, produced 4.0 g/1 of MPA. A glutamate auxotroph, G-42, derived from strain No. 4–23–11 produced 5.8 g/1 of MPA. G-42 grew on l-aspartate instead of l-glutamate, and showed one-third the pyruvate carboxylase activity of the parent. Another glutamate auxotroph, G-78, did not produce MPA but accumulated 1.5 g/1 of acetate in the culture medium, and showed one-fifth the citrate synthase activity of the parent strain.

Anode Performance of Pyrolyzed Bacterial Cellulose in Secondary Lithium-Ion Batteries and the Effect of Added Metal Phthalocyanines

Electrochemical properties of pyrolyzed bacterial cellulose and the effect of the addition of metal phthalocyanines have been investigated for application of the cellulose to electrodes of lithium-ion batteries. The electrodes made of pyrolyzed bacterial cellulose exhibit good stability and relatively high Coulombic efficiency in charge–discharge cycles. Furthermore, the addition of metal phthalocyanines before pyrolysis remarkably increases the charge–discharge capacities of the pyrolyzed bacterial cellulose. We propose the new application of bacterial cellulose as an electrode active material in rechargeable batteries.