Ryozo Numazawa

Bio: Ryozo Numazawa is an academic researcher from Mitsubishi. The author has contributed to research in topics: Carboxylic acid & Alkyl. The author has an hindex of 9, co-authored 26 publications receiving 295 citations.

Biochemical process for purifying contaminated water

Abstract: A process for treating contaminated water containing BOD sources and nitrogen sources, which comprises supplying oxygen or oxygen-containing gas from one side of a gas-permeable membrane to grow microorganisms including aerobic bacteria and anaerobic bacteria on the other side of the gas-permeable membrane, and performing decomposition of the BOD sources and nitrification and denitrification simultaneously by the action of these microorganisms. Especially good results are obtained when a membrane composed of porous hollow fibers is used as the gas-permeable membrane.

Process and apparatus for waste water treatment

Abstract: Waste water containing organic pollutants is purified by biological treatment with aerobic microorganisms supported on hollow fibers having microporous walls through which oxygen is supplied to the microorganisms.

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.

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.

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-Aerated Biofilms for High Rate Biotreatment: Performance Appraisal, Engineering Principles, Scale-up, and Development Requirements

Abstract: Diffusion of the electron acceptor is the rate controlling step in virtually all biofilm reactors employed for aerobic wastewater treatment. The membrane-aerated biofilm reactor (MABR) is a technology that can deliver oxygen at high rates and transfer efficiencies, thereby enhancing the biofilm activity. This paper provides a comparative performance rate analysis of the MABR in terms of its application for carbonaceous pollutant removal, nitrification/denitrification and xenobiotic biotreatment. We also describe the mechanisms influencing process performance in the MABR and the inter-relationships between these factors. The challenges involved in scaling-up the process are discussed with recommendations for prioritization of research needs.