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Dept of Agricultural & Biosystems Engineering University of Arizona 1177 E. Fourth Street Shantz Bldg #38, Room 403 Tucson, AZ 85721-0038 Phone: (520) 621-1753 Fax: (520) 621-3963 Email: abe@arizona.edu Maps: Campus | Tucson

Garcia, Rafael -- Ph.D. 2003
Optimizing the use of lipase in organic solvents for fat modification

Okeson, Carl -- M.S. 1999
Glutamine replenishment and ammonia removal in hybridoma cell cultures via immobilized Glutamine Synthetase

Jack, Darren -- M.S. 1999
Evaluation of two fiberoptic-based solar collection and distribution systems for biogenerative space life support

Reyes, Jose -- Ph.D. 1997
Biophysical Modeling of Agave pacífica under controlled environments

Yue , Chun -- M.S. 1997
Modelling of dynamic liquid hold-up distribution of scale up of the Ebb-and-Flow Bioreactor (EFBR) for "hairy-root"

Garcia, Rafaeal -- Ph.D. 2003
Advisor:  Dr. Mark Riley
Optimizing the use of lipase in organic solvents for fat modification

ABSTRACT:
The effect of organic solvents, pH, aw and other factors on the structure of an enzyme will be investigated using Fourier transform infrared spectroscopy. Changes in enzyme structure will be related to changes in enzyme function. Research will be designed so it will have industrial relevance. The model system will probably be a fat modifying interesterification reaction catalyzed by a lipase. This research should improve the understanding and efficiency of enzymatic processing of materials in non-polar media.

Okeson, Carl -- M.S. 1999
Advisor:  Dr. Mark Riley
Glutamine replenishment and ammonia removal in hybridoma cell cultures via immobilized Glutamine Synthetase 

ABSTRACT:
Hybridoma cells utilize glutamine as their primary nitrogen source and excrete ammonia as a metabolic waste product. This ammonia can quickly accumulate to toxic levels in hybridoma culture media, and can severely reduce monoclonal antibody production (Ozturk et al., 1991. The effect of each enzyme reactant on soluble glutamine synthetase activity was quantified, and enzymatic reaction equilibrium evaluated. Enzyme reaction rates in two culture media, both with and without serum, were compared. Glutamine synthetase was immobilized via three different methods, and their effects compared. Cell sensitivity to each enzymatic reactant was studied. Finally, immobilized glutamine synthetase was incorporated in a hybridoma cultivation, and its effect on culture characteristics evaluated.

Jack, Darren -- M.S. 1999
Advisor:  Dr. Joel Cuello
Evaluation of two fiber optic-based solar collection and distribution systems for biogenerative space life support

ABSTRACT:
Growing plants in an enclosed controlled environment is crucial in developing bioregenerative life Support systems (BLSS) for space applications. There are two major challenges in current designs of a BLSS: the first being the extensive use of highly energy-intensive artificial light sources; and second being the energy wastes incurred through heat dissipations by these lamps. An alternative lighting strategy is the use of a Solar Irradiance Collection, Transmission and Distribution System (SICTDS). An SICTDS can deliver available solar irradiance and reduce heat generation and energy wastes. Two types of SICTDS, a Fresnel-lens collector (Himawari SICTDS) and a parabolic-mirror collector (Optical Waveguide SICTDS ), were evaluated. The light spectral qualities delivered by both SICTDS types were similar to that of terrestrial solar radiation. The overall SICTIDS efficiencies (Himawari = 22.8% and OW 40.5%) and percent visible light of emitted radiation (Himawari, k = 0.39 and OW, k 0.41) were either comparable with or greater than those of the High-Pressure Sodium lamp (25% and k - 0.35, respectively). Fresh and dry weights of lettuce produced under SIMS and HPS lighting were not significantly different.

Reyes, Jose -- Ph.D. 1997
Advisor:  Dr. Joel Cuello
Biophysical Modeling of Agave pacífica under controlled environments

ABSTRACT:
Biophysical models were developed for biomass accumulation, transpiration and carbon dioxide (CO,) assimilation of Agave Pacifica m functions of air C02 concentration, photosynthetic photon flux (PPF) and irrigation interval. Parameter estimation and validation were performed for the Gompertz's equation for biomass accumulation and for the Penman-Monteith equation for transpiration. A new biophysical model for C02 assimilation is proposed consisting of four components: stomatal opening and C02 fixation; malic acid accumulation; malic acid depletion; and photosynthetic carbon assimilation. The main and interactive effects of air C02 concentration, PPF and irrigation interval on biomass accumulation, transpiration and C02 assimilation of Agave pacifica were also determined.

Yue, Chun -- M.S. 1997
Advisor:  Dr. Joel Cuello
Modelling of dynamic liquid hold-up distribution of scale up of the Ebb-and-Flow Bioreactor (EFBR) for "hairy-root"

ABSTRACT:
An ebb-and-flow bioreactor (EFBR) drainage/hold-up simulation model for "hairy" roots was earlier proposed by Cuello (1994). In this study, by experimentally determining the water characteristic curve for Hyoscyamus muticus "hairy root" culture, the proposed model was implemented and was validated using a segmented EFBR (SEFBR). The water characteristic curve was determined at an average porosity of 88%, whereas the SEFBR had an average porosity of 77%. While the simulated dynamic drainage profiles generated large errors owing to the porosity value discrepancy, both the simulated dynamic average hold-up profiles and the simulated dynamic spatial hole-up distribution produced generally acceptable errors of less than 10%.