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.
"Degradation of many toxic compounds using decontaminating enzymes fused with cellulose-binding CBMs has been reported, which enabled a single-step purification and immobilization of fusion proteins into different cellulosic materials (Xu et al. 2002). Cellulosomal systems armed on the cell surface can also be utilized for production of various chemicals like ethyl hexanoate (Su et al. 2010), isoflavone aglycones (Kaya et al. 2008), carnosine (Inaba et al. 2010), chitosan and alginate oligosaccharides (Fukuda et al. 2007; Liu et al. 2009). "
[Show abstract][Hide abstract] ABSTRACT: The adverse climatic conditions due to continuous use of fossil-derived fuels are the driving factors for the development of renewable sources of energy. Current biofuel research focuses mainly on lignocellulosic biomass (LCB) such as agricultural, industrial and municipal solid wastes due to their abundance and renewability. Although many meso-philic cellulolytic microorganisms have been reported, efficient and economical bioconversion to simple sugars is still a challenge. Thermostable cellulolytic enzymes play an indispensible role in degradation of the complex polymeric structure of LCB into fermentable sugar stream due to their higher flexibility with respect to process configurations and better specific activity than the mesophilic enzymes. In some anaerobic thermophilic/thermotolerant microorganisms , few cellulases are organized as unique multifunctional enzyme complex, called the cellulosome. The use of cellulosomal multienzyme complexes for saccharification seems to be a promising and cost-effective alternative for complete breakdown of cellulosic biomass. This paper aims to explore and review the important findings in cellu-losomics and forward the path for new cutting-edge opportunities in the success of biorefineries. Herein, we summarize the protein structure, regulatory mechanisms and their expression in the host cells. Furthermore, we discuss the recent advances in specific strategies used to design new multifunctional cellulosomal enzymes, which can function as lignocellulosic biocatalysts and evaluate the roadblocks in the yield and stability of such designer thermozymes with overall progress in lignocellulose-based biorefinery.
[Show abstract][Hide abstract] 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.
[Show abstract][Hide abstract] 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.
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