title: Theanine production by coupled fermentation with energy transfer employing Pseudomonas taetrolens Y-30 glutamine synthetase and baker's yeast cells.
abstract: Theanine was formed from glutamic acid and ethylamine by coupling the reaction of glutamine synthetase (GS) of Pseudomonas taetrolens Y-30 with sugar fermentation of baker's yeast cells as an ATP-regeneration system. Theanine formation was stimulated by the addition of Mn2+ to the mixture for the coupling. The addition of Mg2+ was less effective. In a mixture containing a larger amount of yeast cells with a fixed level of GS, glucose (the energy source) was consumed rapidly, resulting in a decrease in the final yield of theanine. On the other hand, an increase in GS amounts increased theanine formation in a mixture with a fixed amount of yeast cells. High concentrations of ethylamine enhanced theanine formation whereas inhibited yeast fermentation of sugar and the two contrary effects of ethylamine caused a high yield of theanine based on glucose consumed. In an improved reaction mixture containing 200 mM sodium glutamate, 1,200 mM ethylamine, 300 mM glucose, 50 mM potassium phosphate buffer (pH 7.0), 5 mM MnCl2, 5 mM AMP, 100 units/ml GS, and 60 mg/ml yeast cells, approximately 170 mM theanine was formed in 48 h.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Science and Engineering, Ritsumeikan University, Shiga 525-8577, Japan.
authors.forename: Sachiko
authors.initials: S
authors.lastname: Yamamoto
authors.forename: Mamoru
authors.initials: M
authors.lastname: Wakayama
authors.forename: Takashi
authors.initials: T
authors.lastname: Tachiki
mesh_terms: D000249:Adenosine Monophosphate / Q000494:pharmacology; D002413:Cations, Divalent / Q000494:pharmacology; D003890:Desiccation; D004735:Energy Transfer; D005021:Ethylamines / Q000494:pharmacology; D005285:Fermentation; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism*; D005971:Glutamates / Q000096:biosynthesis*; D008274:Magnesium / Q000494:pharmacology; D011549:Pseudomonas / Q000201:enzymology*; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002413:Cations, Divalent; D005021:Ethylamines; D005971:Glutamates; D000249:Adenosine Monophosphate; C026166:theanine; D005974:Glutamate-Ammonia Ligase; D008274:Magnesium; C041564:ethylamine