Complex physiology and compound stress responses during fermentation of alkali-pretreated corn stover hydrolysate by an Escherichia coli ethanologen.

The physiology of ethanologenic Escherichia coli grown anaerobically in alkali-pretreated plant hydrolysates is complex and not well studied. To gain insight into how E. coli responds to such hydrolysates, we studied an E.

Kinetic modeling of free fatty acid production in Escherichia coli based on continuous cultivation of a plasmid free strain.

The microbial production of free fatty acids (FFAs) and reduced derivatives is an attractive process for the renewable production of diesel fuels. Toward this goal, a plasmid-free strain of Escherichia coli was engineered to produce FFAs by integrating three copies of a thioesterase gene from Umbellularia californica (BTE) under the control of an inducible promoter onto the chromosome. In batch culture, the resulting strain produced identical titers to a previously reported strain that expressed the thioesterase from a plasmid.

Membrane stresses induced by overproduction of free fatty acids in Escherichia coli.

Microbially produced fatty acids are potential precursors to high-energy-density biofuels, including alkanes and alkyl ethyl esters, by either catalytic conversion of free fatty acids (FFAs) or enzymatic conversion of acyl-acyl carrier protein or acyl-coenzyme A intermediates. Metabolic engineering efforts aimed at overproducing FFAs in Escherichia coli have achieved less than 30% of the maximum theoretical yield on the supplied carbon source. In this work, the viability, morphology, transcript levels, and protein levels of a strain of E.

Bacterial production of free fatty acids from freshwater macroalgal cellulose.

The predominant strategy for using algae to produce biofuels relies on the overproduction of lipids in microalgae with subsequent conversion to biodiesel (methyl-esters) or green diesel (alkanes). Conditions that both optimize algal growth and lipid accumulation rarely overlap, and differences in growth rates can lead to wild species outcompeting the desired lipid-rich strains. Here, we demonstrate an alternative strategy in which cellulose contained in the cell walls of multicellular algae is used as a feedstock for cultivating biofuel-producing microorganisms.

Practical application of synthetic biology principles.

Synthetic biology can be defined as the "repurposing and redesign of biological systems for novel purposes or applications, " and the field lies at the interface of several biological research areas. This broad definition can be taken to include a variety of investigative endeavors, and successful design of new biological paradigms requires integration of many scientific disciplines including (but not limited to) protein engineering, metabolic engineering, genomics, structural biology, chemical biology, systems biology, and bioinformatics. This review focuses on recent applications of synthetic biology principles in three areas: (i) the construction of artificial biomolecules and biomaterials; (ii) the synthesis of both fine and bulk chemicals (including biofuels); and (iii) the construction of "smart" biological systems that respond to the surrounding environment.

Enzyme immobilization via silaffin-mediated autoencapsulation in a biosilica support.

Enzymes and other biomolecules are often immobilized in a matrix to improve their stability or to improve their ability to be reused. Performing a polycondensation reaction in the presence of a biomolecule of interest relies on random entrapment events during polymerization and may not ensure efficient, homogeneous, or complete biomolecule encapsulation. To overcome these limitations, we have developed a method of incorporating autosilification activity into proteins without affecting enzymatic functionality.

Morphology of artificial silica matrices formed via autosilification of a silaffin/protein polymer chimera.

Protein polymers (long-chain proteins in which a specific amino acid sequence "monomer" is repeated through the molecule) are found widely in nature, and these materials exhibit a diverse array of physical properties. One class of self-assembling proteins is hydrophobic-polar (HP) protein polymers capable of self-assembly under the appropriate solution conditions. We generated a chimeric protein consisting of an HP protein polymer monomer unit, EAK 1 (sequence n-AEAEAKAKAEAEAKAK-c), and a silaffin peptide, R5 (sequence: n-SSKKSGSYSGSKGSKRRIL-c).