Yeast cell-surface expression of chitosanase from Paenibacillus fukuinensis
ABSTRACT To produce chitoorigosaccharides using chitosan, we attempted to construct Paenibacillus fukuinensis chitosanase-displaying yeast cells as a whole-cell biocatalyst through yeast cell-surface engineering. The localization of the chitosanase on the yeast cell surface was confirmed by immunofluorescence labeling of cells. The chitosanase activity of the constructed yeast was investigated by halo assay and the dinitrosalicylic acid method.
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ABSTRACT: A classic argument for flexible exchange rates is that the exchange rate plays a 'shock-absorber' role in an open economy vulnerable to country-specific shocks. This paper presents a sharp counter-example to this argument within a very conventional open economy model. Countries are subject to unpredictable shocks to world demand for their goods. Efficient adjustment is prevented, both by sticky nominal wages and by the absence of a market for hedging consumption risk internationally. A flexible exchange rate policy acts perfectly as a 'shock-absorber', fully stabilizing output and replicating the flexible wage outcome. Despite this, a policy that fixes the exchange rate may be welfare superior, even though fixed exchange rates cause output to deviate from the flexible wage outcome. Moreover, an optimal monetary rule in this environment would always dampen exchange rate movements, and may even be a fixed exchange rate.SSRN Electronic Journal 11/2001; DOI:10.2139/ssrn.1009384
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ABSTRACT: This review gives an overview of different yeast strains and enzyme classes involved in yeast whole-cell biotransformations. A focus was put on the synthesis of compounds for fine chemical and API (= active pharmaceutical ingredient) production employing single or only few-step enzymatic reactions. Accounting for recent success stories in metabolic engineering, the construction and use of synthetic pathways was also highlighted. Examples from academia and industry and advances in the field of designed yeast strain construction demonstrate the broad significance of yeast whole-cell applications. In addition to Saccharomyces cerevisiae, alternative yeast whole-cell biocatalysts are discussed such as Candida sp., Cryptococcus sp., Geotrichum sp., Issatchenkia sp., Kloeckera sp., Kluyveromyces sp., Pichia sp. (including Hansenula polymorpha = P. angusta), Rhodotorula sp., Rhodosporidium sp., alternative Saccharomyces sp., Schizosaccharomyces pombe, Torulopsis sp., Trichosporon sp., Trigonopsis variabilis, Yarrowia lipolytica and Zygosaccharomyces rouxii.Microbial Cell Factories 09/2008; 7:25. DOI:10.1186/1475-2859-7-25 · 4.25 Impact Factor
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ABSTRACT: Chitosanase from Paenibacillus fukuinensis D2 is an attractive enzyme, and it exhibits both chitosanase and beta-1, 4 glucanase activities. In our previous study, we generated P. fukuinensis chitosanase-displaying yeast cells using a yeast cell surface-displaying system. Chitosanase-displaying yeast can be utilized as a chitosanase cluster without many time-consuming purification steps. In this study, using the system, we have investigated whether Glu302, which is supposed as a putative proton acceptor, is an essential amino acid residue for exhibiting chitosanase activity and analyzed the contribution of mutual interaction between Glu302 and Asn312 to the activity. A mutant library in which Glu302 and Asn312 were comprehensively substituted by the other amino acid residues was constructed on the yeast cell surface. From the results of chitosanase and beta-1, 4 glucanase activity assays, we demonstrated that Glu302 was a proton acceptor for chitosanase activity, and Asn312 also participated in the hydrolysis of chitosan and cellulose.Applied Microbiology and Biotechnology 07/2009; 85(1):95-104. DOI:10.1007/s00253-009-2041-5 · 3.81 Impact Factor