New catalytic strategies for α,ω-diols production from lignocellulosic biomass.

Catalytic strategies for the synthesis of 1,5-pentanediol (PDO) with 69% yield from hemicellulose and the synthesis of 1,6-hexanediol (HDO) with 28% yield from cellulose are presented. Fractionation of lignocellulosic biomass (white birch wood chips) in gamma-valerolactone (GVL)/H2O generates a pure cellulose solid and a liquid stream containing hemicellulose and lignin, which is further dehydrated to furfural with 85% yield. Furfural is converted to PDO with sequential dehydration, hydration, ring-opening tautomerization, and hydrogenation reactions. Acid-catalyzed cellulose dehydration in tetrahydrofuran (THF)/H2O produces a mixture of levoglucosenone (LGO) and 5-hydroxymethylfurfural (HMF), which are converted with hydrogen to tetrahydrofuran-dimethanol (THFDM). HDO is then obtained from hydrogenolysis of THFDM. Techno-economic analysis demonstrates that this approach can produce HDO and PDO at a minimum selling price of $4090 per ton.

Chemicals from Biomass: Combining Ring-Opening Tautomerization and Hydrogenation Reactions to Produce 1,5-Pentanediol from Furfural.

A process for the synthesis of 1,5-pentanediol (1,5-PD) with 84 % yield from furfural is developed, utilizing dehydration/hydration, ring-opening tautomerization, and hydrogenation reactions. Although this process has more reaction steps than the traditional direct hydrogenolysis of tetrahydrofurfuryl alcohol (THFA), techno-economic analyses demonstrate that this process is the economically preferred route for the synthesis of biorenewable 1,5-PD. 2-Hydroxytetrahydropyran (2-HY-THP) is the key reaction pathway intermediate that allows for a decrease in the minimum selling price of 1,5-PD. The reactivity of 2-HY-THP is 80 times greater than that of THFA over a bimetallic hydrogenolysis catalyst. This enhanced reactivity is a result of the ring-opening tautomerization to 5-hydoxyvaleraldehyde and subsequent hydrogenation to 1,5-PD.

Bacterial delivery of Staphylococcus aureus α-hemolysin causes regression and necrosis in murine tumors.

Bacterial therapies, designed to manufacture therapeutic proteins directly within tumors, could eliminate cancers that are resistant to other therapies. To be effective, a payload protein must be secreted, diffuse through tissue, and efficiently kill cancer cells. To date, these properties have not been shown for a single protein. The gene for Staphylococcus aureus α-hemolysin (SAH), a pore-forming protein, was cloned into Escherichia coli. These bacteria were injected into tumor-bearing mice and volume was measured over time. The location of SAH relative to necrosis and bacterial colonies was determined by immunohistochemistry. In culture, SAH was released and killed 93% of cancer cells in 24 hours. Injection of SAH-producing bacteria reduced viable tissue to 9% of the original tumor volume. By inducing cell death, SAH moved the boundary of necrosis toward the tumor edge. SAH diffused 6.8 ± 0.3 µm into tissue, which increased the volume of affected tissue from 48.6 to 3,120 µm(3). A mathematical model of molecular transport predicted that SAH efficacy is primarily dependent on colony size and the rate of protein production. As a payload protein, SAH will enable effective bacterial therapy because of its ability to diffuse in tissue, kill cells, and expand tumor necrosis.

Identification of Staphylococcus aureus α-hemolysin as a protein drug that is secreted by anticancer bacteria and rapidly kills cancer cells.

Targeted bacterial delivery of anticancer proteins has the ability to overcome therapeutic resistance in tumors that limits the efficacy of chemotherapeutics. The ability of bacteria to specifically target tumors allows for delivery of aggressive proteins that directly kill cancer cells and cannot be administered systemically. However, few proteins have been tested for this purpose. To identify effective molecules, we systematically sorted proteins that have been shown to cause mammalian cell death. The genes for five proteins were selected and cloned into Escherichia coli and Salmonella. Supernatant from cultures of the transformed bacteria was applied to flasks of MCF-7 mammary carcinoma cells to identify proteins that (1) were expressed, (2) secreted, and (3) rapidly killed cancer cells. Time-lapse images were taken to visualize mammalian cell morphology. Of the investigated proteins, α-hemolysin from Staphylococcus aureus (SAH) was the most promising because it was secreted, caused trauma to cellular membranes, and induced oncosis in 18 min. After exposure for 6 h, SAH decreased cell viability by 90%. In comparison, the positive control, Pseudomonas aeruginosa exotoxin A (PEA), required 11 days to achieve a similar effect, when administered at 3,000 times its LC50 . The maximum death rate induced by SAH was calculated to be a reduction in cell viability of 7.1% per min, which was 200-fold faster than the PEA control. Two proteins, Dermonecrotic Toxin and Phospholipase C were active when extracted from the bacterial cytoplasm but were not secreted. This investigation revealed for the first time SAH as a potent anticancer drug for delivery by bacteria because of its ability to be secreted in a fully functional form and aggressively kill cancer cells.