DEVELOPMENT OF NOVEL BIO- AND HETEROGENEOUS CATALYSTS FOR THE PRODUCTION OF BIO- AND GREEN DIESEL

Diminishing petroleum reserves and increasing environmental awareness has led to an urgent need to develop alternative fuels, such as biodiesel. Enzymatic trans/-esterification of waste cooking oils with a lipase catalyst is a promising environmentally-friendly process to produce biodiesel, compared to the current industrial chemical process. Despite several advantages, there are a few technical and economical obstacles that limit this process, such as insufficient availability of large quantities of inexpensive lipase suitable for catalysis, and bad performance at low temperatures due to biodiesel’s low cetane number. These limitations are addressed in this dissertation using genetic engineering of plants to produce the enzyme lipase, and hydrodeoxygenation of biodiesel to produce green diesel. The specific objectives include: • Cloning and over-expressing recombinant lipase from T. lanuginosus and C. antarctica in tobacco and A. thaliana in order to develop an inexpensive biocatalyst. • Developing and characterizing supported molybdenum and cobalt promoted catalysts in the hydrodeoxygenation reaction of biodiesel for the production of green diesel to promote oils’ performance. The major findings are: (i) Lipase genes can be constitutively expressed in tobacco and A. thaliana without adversely affecting plant growth. Plants offer a promising platform for producing recombinant enzymes for biodiesel production; (ii) Optimization of hydrodeoxygenation process parameters such as reduction temperature, hydrogen gas flow rate, and reaction temperature can significantly increase green diesel yield; (iii) Cobalt added as a promoter in the supported molybdenum catalysts can significantly increase the catalytic activity, selectivity, and stability; and (iv) The choice of support in the heterogeneous molybdenum catalysts can also have a considerable effect on the green diesel yield

Abelian flux induced magnetic frustrations of spinor boson superfluids on a square lattice

Inspired by recent experimental advances to generate Abelian flux for neutral cold atoms and photons moving in a lattice, we investigate the possible effects of the $\pi$ flux through a unit cell in the pseudo-spin 1/2 spinor boson Hubbard model in a square lattice. We find that the $\pi$ flux induces a dramatic interplay between the charge and the spin which leads to a frustrated superfluid. We develop a new and systematic "order from quantum disorder" analysis to determine not only the true quantum ground state, but also the excitation spectrum. The superfluid ground state has a 4 sublattice $90^{\circ}$ coplanar spin structure which supports 4 linear gapless modes with 3 different velocities. We speculate the transition from the weak coupling frustrated SF to the strong coupling Ferromagnetic Mott state to be in a new universality class of non-Ginsburg Landau type. These novel phenomena may be observed in these recent cold atom and photonic experiments.Comment: 5 pages, REVTEX-4, 3 figure

Transesterification of waste vegetable oil by Thermomyces lanuginosus lipase immobilized on zeolite ZSM-5

In this thesis, the effect of organic solvent-cosolvent system, temperature, methanol concentration, water content and used enzyme washing method on transesterification of waste vegetable oil catalyzed by Thermomyces lanuginosus lipase immobilized on zeolite ZSM-5 was investigated. Four organic solvents, one co-solvent, three reaction temperatures, three methanol addition methods, four different water content and two used-enzyme washing methods were assessed. Optimal conditions were obtained with n-hexane as solvent, 5 vol.% tert-butanol as co-solvent, 25°C reaction temperature, batch addition of 3 equivalent molar methanol, water content equivalent to 7.5% by weight, and used-enzyme washing method B. It was also confirmed that the transesterification reaction catalyzed by used Thermomyces lanuginosus lipase immobilized on zeolite ZSM-5 was limited by the concentration of acyl acceptor, and that active water loss was related to enzyme activity lost after every reaction cycle