Immobilized Enzymes for Waste Stream Valorization
Food industry waste streams represent a significant environmental burden. These waste streams, rich in sugars, proteins, and lipids, can be transformed into value-added products. Enzymes provide a selective and greener route of synthesis, but lack stability in extreme environments, and the ability t...
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| Other Authors: | , , |
| Format: | Thesis |
| Language: | English |
| Published: |
2018
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| Subjects: | |
| Online Access: | https://hdl.handle.net/1813/59598 http://dissertations.umi.com/cornellgrad:10955 https://doi.org/10.7298/X4HM56PG |
| Summary: | Food industry waste streams represent a significant environmental burden. These waste streams, rich in sugars, proteins, and lipids, can be transformed into value-added products. Enzymes provide a selective and greener route of synthesis, but lack stability in extreme environments, and the ability to be reused. Therefore, the present work studied immobilized enzymes for practical application in two major waste streams: oil and dairy. First, lipase B from Candida antarctica (E.C. 3.1.1.3) was immobilized within cross-linked microparticles (CLMP) displaying varying scales of support, and the influence of these nano- and macroscale support materials on lipase activity and stability was studied. Kinetic analysis and extreme environment testing revealed that that polydicyclopentadiene macrostructure had the greatest influence on stability. These CLMPs successfully produced surfactants from lauric acid and D-glucose. However, the ~10 µm particles were unrecoverable from viscous solvents. Next, lipase was immobilized into macroscale, polymerized high internal phase emulsions (HIPE) to facilitate ease of handling. After fabrication, HIPEs displayed an increase in activity (139±9.7%) over native lipase. However, lipase was weakly immobilized, and retained less than 10% relative activity after 5 washes. HIPEs retained above 40% relative activity after exposure to pH 3, 7, and 10 for 24 hours, effectively expanding the working range of lipase. HIPEs also displayed an increase in relative activity after storage at 20 ˚C and 40 ˚C for 24 hours and retained greater than 40% activity after storage in 50 ˚C and 60 ˚C for 24 hours. These macroscale HIPEs were recoverable from reaction media but require further optimization to increase protein retention. Finally, β-galactosidase from Aspergillus oryzae (E.C. 3.2.1.23) and glucose isomerase (E.C. 5.3.1.5) were co-immobilized within a cross-linked enzyme aggregate (combi-CLEA) for dairy waste upcycling. The β-galactosidase within the combi-CLEA retained approximately 10% activity ... |
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