Thesis (M.S.)--Rutgers University, 2008. / "Graduate Program in Chemical and Biochemical Engineering." Includes bibliographical references (p. 64-67).

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 157-170). Also available in print.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains v, 70 p. : ill. Includes abstract. Includes bibliographical references.

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Biphasic systems have been studied for in situ product removal (ISPR), and have shown improvements in bioreactor performance. With immiscible solvents, concerns associated with solvent biocompatibility, bioavailability and operation have been identified. One alternative is a solid-liquid system in which polymer beads are used, absorbing and removing target compounds from the aqueous phase while maintaining equilibrium conditions. In such systems, the capability of a polymer to absorb the compound of interest is an important parameter. This work has identified polymer properties that may be important to the interaction between polymers and target compounds for selected biotransformation molecules including 2-phenylethanol, cis-1,3-indandiol, iso-butanol, succinic acid and 3-hydroxybutyrolactone. Furthermore, the biotransformation from L-phenylalanine to 2-phenyethanol, an important aroma compound in industry, was examined in detail. It was found that relatively hydrophobic compounds tend to be absorbed by polymers better than hydrophilic ones based on partition coefficient tests. Since all of the biotransformation molecules tested have polar functional groups such as alcohol, acid and lactone, polar polymers such as Hytrel® performed better than non-polar polymers such as Kraton® possibly due to the hydrogen-bonding interaction between the polymer and the solute. Crystallinity and intermolecular hydrogen-bonding were also found to be important polymer properties. Hytrel® 8206 was identified as the best working polymer to absorb 2-phenylethanol. A solid-liquid batch mode two phase partitioning bioreactor (TPPB) with 500 g Hytrel® generated an overall 2-PE concentration of 13.7 g/L, the highest reported in the current literature. This was based on a polymer phase concentration of 88.74 g/L and aqueous phase concentration of 1.2 g/L. Better results were achieved via contact with more polymers with the aqueous phase applying a semi-continuous reactor configuration. In this system, a final 2-PE concentration (overall) of 20.4 g/L was achieved. The overall productivities of these two reactor systems were 0.38 g/(L-h) and 0.43 g/(L-h), respectively. This experiment successfully demonstrated that with the appropriate selection of polymer, solid-liquid TPPB systems were able to greatly enhance bioproductions associated with end product inhibition in terms of final product concentration and productivity. The ease of operation is also attractive compared to two liquid phase systems. / Thesis (Master, Chemical Engineering) -- Queen's University, 2009-07-02 11:37:33.83

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ABSTRACT White-rot fungi and their enzymes are receiving increasing attention for biotechnological applications in the pulp and paper industry as alternatives to conventional bleaching. Laccase has been identified as one of the enzymes that plays a major role in lignin degradation. Laccase only attacks phenolic subunits of lignin, but its substrate range can be extended to non-phenolic subunits by the inclusion of a mediator. The use of this enzyme was, therefore, not successful in pulp bleaching trials until the discovery of mediators. Although the existence of natural mediators has not been confirmed, various components have been identified that are able to act as mediators. Improved methods of laccase production could benefit the industrial utilisation of the enzyme. White-rot fungi constitutively produce low concentrations of laccase, but higher concentrations can be obtained with the inclusion of inducers in the cultivation media. The enzyme is mainly produced during the stationary growth phase of the fungi, but various factors such as glucose, nitrogen and pH can influence levels of laccase production. The enzyme does not only hold potential for biological pulp bleaching operations, but also has application in bioremediation, the textile dye industry as well as the food and beverage industries.

YEAST DIVERSITY IN BLUE MOULD RIPENED CHEESES. ABSTRACT During the ripening process of blue veined cheese, different microbial groups interact and contribute to the final product. One of the most important of these groups are yeast. Further studies are needed to clarify their specific contribution to the ripening process. In order to accomplish this, a suitable and satisfactory enumeration medium is needed. Consequently, ten selective media were evaluated for their potential to inhibit and suppress the growth of moulds and bacteria without affecting the yeasts. Based on statistically compared data, no significant difference could be found amongst the ten media, except for one. Further studies were performed on the three media considered to be the most effective, MEA + Ox, MEA + NaCl and MEA + BP based on qualitative results. Accordingly, the three selected media were evaluated based on their ability to support the growth of the five most frequently occurring yeast species in blue veined cheese. No significant difference was obtained between two of the three media. MEA + NaCl however, was unable to support the growth of two of the five most dominant yeast species. MEA + Ox and MEA + BP proved to be superior for the enumeration and isolation of yeasts from blue veined cheese. DRBC, RBC and DG18 proved satisfactory regarding the enumeration of yeasts, whereas OGGY, MEA + SP and molybdate containing media are not recommended. Key words: Selective media, Yeasts, Moulds, Enumeration

Laboratory canning and evaluation of dry beans are common practices for testing canning quality of cultivars before commercial release to canning industries. Suitable laboratory canning and evaluation procedures for small white beans in tomato sauce were identified. Standard values for choice and standard grade beans for laboratory evaluation of canning quality were defined, using four small white bean cultivars from nine localities during the 2000/01 season. The cultivar Teebus was used as reference standard for choice grade beans and its canning quality complied with international guidelines when the modified canning technique (MCT) was used. From the laboratory and modified canning evaluation procedures hydration coefficient, percentage washed drained weight, visual appearance (scale 1 to 10), splits (scale 1 to 10), texture (kg.100 g -1 .12 s -1 ), size, clumping, L-values, aL-values and bL-values were identified as suitable canning parameters for small scale evaluation of beans. Beans canned with the MCT were also canned and evaluated industrially and results compared. The interpretation of the different canning parameters with laboratory and industrial canning were simplified by the use of canonical variate analysis (CVA). Canonical variate analysis indicated the same groupings for cultivars according to choice and standard grade canning quality for laboratory and industrial canned beans. Laboratory canning and evaluation could be used in the evaluation of the canning quality of beans intended for industrial canning. Canning quality of seven small white bean cultivars from 33 localities and two seasons was determined with the MCT and CVA. Cultivars with acceptable and unacceptable canning quality were identified using laboratory evaluation and CVA. The CVA resulted in a prediction model for canonical variates 1 and 2 (CV 1 and CV 2) by identifying two discriminative equations for CV 1 and CV 2 scores. The CVA for environments identified differences in the canning quality of beans from different regions, while also indicating seasonal differences. The canning quality of dry bean cultivars from different environments can be determined using CVA. The model equations for the prediction of the canning quality of small white beans were validated on four cultivar samples from four regions (2000/01 season) and 24 breeding samples from three localities (2002/03 season) that were not included in the development of the model. The CVA and the model identified the same entries from breeding trials over localities not to be significantly different from Teebus (P > 0.05) in canning quality, but were unable to group cultivars statistically correct according to choice grade. The model was however capable of grouping standard and choice grade cultivars separately. The model could be applied to identify breeding trial entries as choice grade and to identify entry x locality interactions. The use of small-scale canning and evaluation procedures in combination with CVA could be employed to classify cultivar canning quality as either choice- or standard grade and to determine environmental canning quality. These techniques could be used, with the assistance of the prediction model to compare samples from a breeding program with a reference standard.