Akihiro Sakimae

Bio: Akihiro Sakimae is an academic researcher from Mitsubishi. The author has contributed to research in topics: Alkyl & Carboxylic acid. The author has an hindex of 12, co-authored 56 publications receiving 386 citations.

Multi-layered porous hollow fiber membrane for use in cell culture

Abstract: A method for culturing cells by supplying oxygen to a culture medium through a multilayer composite membrane consisting of a porous layer(s) and a nonporous layer(s) having a thickness of less than 10 micrometers laminated one after the other. By using this multilayer composite membrane for supplying oxygen to the culture medium, oxygen can be supplied to the culture medium and/or the culture broth without causing foaming in the culture medium, cell growth inhibition or reduction in productivity of cellular products.

Preparation of immobilized enzymes from acrylic monomers under γ‐ray irradiation

Abstract: Immobilized glucoamylase, invertase, and β-galactosidase were prepared by using 2-hydroxyethyl acrylate and dimethylacrylamide under γ-ray irradiation. In the case of 2-hydroxyethyl acrylate, the monomer-enzyme solution was changed to the gel by irradiation of less than 1.0 Mrad, but it was difficult to eliminate enzyme leakage from the gel. When leakage was eliminated by increased irradiation, the activities of the gels were very low. In the case of dimethylacrylamide, the monomer–enzyme solution was changed to a gel by irradiation of 1.0 Mrad; leakage could be eliminated by irradiation of 2.0 Mrad. This gel possessed very high activity. In the case of acrylic acid-sodium acrylate, the monomer–enzyme solution could not be changed to a gel. In preparing gels, high concentrations of enzyme protein had a tendency to obstruct gelation.

Nucleotide Sequence of the Gene for a Thermostable Esterase from Pseudomonas putida MR-2068

Abstract: The esterase gene (est) of Pseudomonas putida MR-2068 was cloned into Escherichia coli JM109. An 8-kb inserted DNA directed synthesis of an esterase in E. coli. The esterase gene was in a 1.1-kb PstI-ClaI fragment within the insert DNA. The complete nucleotides of the DNA fragment containing the esterase gene were sequenced and found to include a single open reading frame of 828 bp coding for a protein of 276 amino acid residues. The open reading frame was confirmed by N-terminal amino acid sequence analysis of the purified esterase. A potential Shine-Dalgarno sequence is followed by the open reading frame. The esterase activity of the recombinant E. coli was more than 200 times higher than that of parental strain, P. putida MR-2068.

Screening of Microorganisms Producing D-β-Acetylthioisobutyric Acid from Methyl DL-β-Acetylthioisobutyrate

Abstract: Microorganisms producing D-β-acetylthioisobutyric acid from methyl D-β-acetylthioisobutyrate were screened from stock cultures. The D-β-acetylthioisobutyric acid-producing ability was found in 15 strains belonging to the genera Pseudomonas, Agrobacterium, Enterobacter, Cellulomonas, Rhodococcus, Brevibacterium, and Torulopsis. A strain of Pseudomonas fluorescens, IFO 3081, was selected as the best microorganism. The cells having activity (558 units/g of dry cells) could be easily prepared by cultivation at 25°C at pH 6.6 for 24 hr in a glucose-containing medium. The D-form of methyl DL-β-acetylthioisobutyrate was selectively hydrolyzed with the cells so that D-β-acetylthioisobutyric acid (97.2% enantiomeric excess) was produced in a high yield.

Preparation of immobilized invertase

Abstract: Immobilized invertase was prepared by ionically binding the enzyme to diethylaminoacetyl cellulose (DEAA-cellulose). DEAA-cellulose-invertase complex was quite stable to electrolyte in the range of pH 5–7. Bound invertase was less active than the native enzyme, and approximately 55–70% of the enzyme activity was lost on binding. The complex was stable for 9 days' continuous inversion in a column system at 30°C, but was rather unstable at 40°C. Heat stability and the effect of temperature on the reaction rate of the complex were almost identical with those of the native enzyme.

Microbial carboxyl esterases: classification, properties and application in biocatalysis

Abstract: Esterases (EC 3.1.1.x) represent a diverse group of hydrolases catalyzing the cleavage and formation of ester bonds and are widely distributed in animals, plants and microorganisms. Beside lipases, a considerable number of microbial carboxyl esterases have also been discovered and overexpressed. This review summarizes their properties and classification. Special emphasis is given on their application in organic synthesis for the resolution of racemates and prostereogenic compounds. In addition, recent results for altering their properties by directed evolution are presented.

Production and applications of esterases

Abstract: Esterase plays a major role in the degradation of natural materials and industrial pollutants, viz, cereal wastes, plastics, and other toxic chemicals It is useful in the synthesis of optically pure compounds, perfumes, and antioxidants The potential applications of esterase with reference to agriculture, food, and pharmaceutical industries, are discussed in this review Promising applications in this avenue can be supported by appropriate production strategies

Membrane module for gas transfer and membrane supported biofilm process

Abstract: An apparatus to transfer gas to or from a liquid has a flexible and oxygen permeable but liquid water impermeable membrane, a flexible and gas permeable spacer, an inlet conduit, an outlet conduit and a non-rigid restraint system When used for treating wastewater, an aerobic biofilm is cultured adjacent the planar elements, an anoxic biofilm is cultivated adjacent the aerobic biofilm and the wastewater is maintained in an anaerobic state A first reactor for treating wastewater has an anaerobic section, a plurality of gas transfer membrane modules, and an aerobic section A biofilm is cultivated on the surface of the gas transfer membranes in fluid communication with the anaerobic section Biological reduction of COD, BOD, nitrogen and phosphorous are achieved In a second reactor, phosphorous is also removed chemically in a precipitation branch