Keith E. J. Tyo

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Taxol (paclitaxel) is a potent anticancer drug first isolated from the Taxus brevifolia Pacific yew tree. Currently, cost-efficient production of Taxol and its analogs remains limited. Here, we report a multivariate-modular approach to metabolic-pathway engineering that succeeded in increasing titers of taxadiene--the first committed Taxol(More)
Engineering robust microbes for the biotech industry typically requires high-level, genetically stable expression of heterologous genes and pathways. Although plasmids have been used for this task, fundamental issues concerning their genetic stability have not been adequately addressed. Here we describe chemically inducible chromosomal evolution (CIChE), a(More)
Terpenoids represent a diverse class of molecules that provide a wealth of opportunities to address many human health and societal issues. The expansive array of structures and functionalities that have been evolved in nature provide an excellent pool of molecules for use in human therapeutics. While this class of molecules has members with therapeutic(More)
A novel, quantitative method for detecting poly-3-hydroxybutyrate (PHB) amounts in viable cells was developed to allow for high-throughput screening of mutant libraries. The staining technique was demonstrated and optimized for the cyanobacterium Synechocystis sp. strain PCC6803 and the eubacterium Escherichia coli to maximize the fluorescence difference(More)
The yeast Saccharomyces cerevisiae is a widely used model organism for studying cell biology, metabolism, cell cycle and signal transduction. Many regulatory pathways are conserved between this yeast and humans, and it is therefore possible to study pathways that are involved in disease development in a model organism that is easy to manipulate and that(More)
The yeast Saccharomyces cerevisiae is a widely used platform for the production of heterologous proteins of medical or industrial interest. However, heterologous protein productivity is often restricted due to the limitations of the host strain. In the protein secretory pathway, the protein trafficking between different organelles is catalyzed by the(More)
Poly-3-hydroxybutyrate (PHB) titers in Escherichia coli have benefited from 10+ years of metabolic engineering. In the majority of studies, PHB content, expressed as percent PHB (dry cell weight), is increased, although this increase can be explained by decreases in growth rate or increases in PHB flux. In this study, growth rate and PHB flux were(More)
Hyaluronic acid (HA) is an important biomaterial with functional medical and cosmetic applications. As its synthesis has been recently reported in recombinant bacteria, it is of interest to develop a high throughput screening method for the rapid isolation of HA accumulating strains transformed by combinatorial libraries. Here we report a novel two-step(More)
The protein secretory pathway must process a wide assortment of native proteins for eukaryotic cells to function. As well, recombinant protein secretion is used extensively to produce many biologics and industrial enzymes. Therefore, secretory pathway dysfunction can be highly detrimental to the cell and can drastically inhibit product titers in biochemical(More)
Yeast Saccharomyces cerevisiae has become an attractive cell factory for production of commodity and speciality chemicals and proteins, such as industrial enzymes and pharmaceutical proteins. Here we evaluate most important expression factors for recombinant protein secretion: we chose two different proteins (insulin precursor (IP) and α-amylase), two(More)