Extraction, reimmobilization and characterization of spent immobilized lipase
Currently, lipases are considered as one of the important catalysts in substituting the use of chemical reactions in a wide variety of processes. In 2015, the report estimated that the U.S. enzyme's market had a high demand for processed foods and synthesis reactions, which generated more th...
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| Main Author: | |
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| Format: | Thesis |
| Language: | English |
| Published: |
2020
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/93080/1/FBSB%202020%2022%20IR.pdf |
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| Summary: | Currently, lipases are considered as one of the important catalysts in substituting
the use of chemical reactions in a wide variety of processes. In 2015, the report
estimated that the U.S. enzyme's market had a high demand for processed
foods and synthesis reactions, which generated more than USD 1 billion in sales.
However, the reusability of the industrial immobilized lipase was limited only after
several cycles of reactions. After that, the spent immobilized lipase will be
replaced with the new immobilized lipase. The inability to reuse the spent
immobilized lipase leads to an increased cost required for the new uptake of the
enzyme. Practically in industry, the spent immobilized lipase is a waste from
industrial users. The spent immobilized lipase still has potential use even though
the activity was lower than the new immobilized lipase. There was no study done
on the extraction and reimmobilization of the enzyme from the spent immobilized
lipase. Therefore, the objective of this research is to study the feasibility of the
spent lipase to be extracted, reimmobilized, and characterized.
General methodology involved the recovery of the spent immobilized lipase via
chemical and mechanical extraction. The chemical extraction approach via
Reverse Micelles Extraction (RME) showed the highest lipase recovery, which
was 66% compared to the 34% of lipase yield obtained from the mechanical
extraction method. The extracted lipase was reimmobilized via simple
adsorption into the ethanol pretreated carrier. The characterization of the
reimmobilized lipase at different pH and temperature was conducted. The
optimum conditions of immobilization resulted in 96% of the extracted lipase
being immobilized. The reimmobilized lipase optimum activity was at 50°C and
pH 6. The reimmobilized lipase was incubated for 20 h in pH 6 buffer at 50°C of
water bath shaker. The reimmobilized lipase still had 27% residual activity after
18 h of incubation, which indicated higher thermal stability compared to the free
lipase. The Scanning Electron Microscope (SEM) was used to study the morphology of
the reimmobilized lipase. The morphological of immobilized lipase was analyzed
based on the pore and the particle sizes of the support. SEM also showed oil on
the surface of immobilized lipase before and after the solvent treatment. The
structural analysis of free lipase and reimmobilized lipase was determined by
Fourier-transform infrared spectroscopy (FTIR). The structures of the amide
group I (CO stretch) and amide group II (NH bend), which formed the functional
group of the free commercial lipase, extracted lipase and reimmobilized lipase,
had been identified. In conclusion, the free lipase was successfully extracted
from the spent immobilized lipase and reimmobilized into Accurel MP1008
carrier. It exhibited high thermal stability, and the reusability of the spent enzyme
will promote continued use of industrial lipase and reduce the cost of the
manufacturing process. |
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