Abstract
The ability of Commercial Native Linamarase (CNLIN) and Engineered Linamarase (GELIN) extracts from <em>Saccharomyces cerevisiae</em> to hydrolyse cassava linamarin was challenged. CNLIN acting as control was used together with GELIN extracts from <em>Saccharomyces cerevisiae</em> to evaluate the kinetic data for test enzymes at pH 3.5, 6.8 and 10.5, respectively and ambient temperature (35°C). Data obtained from the varying activity versus substrate concentrations were fitted with the Michaelis-Menten plots and Lineweaver-Burk model to obtain maximum velocity (V<sub>max</sub>), affinity coefficient (K<sub>m</sub>), physiological efficiency (K<sub>m</sub>/V<sub>max</sub>) and r<sup>2</sup> (linear regressing coefficient). The results indicated that the engineered linamarase conferred different enzyme kinetic data showing degradation of cassava linamarin by CNLIN and GELIN from <em>Saccharomyces cerevisiae</em> at the optimum pH and temperature. The relation was best described by the characteristic sigmoid Michaelis-Menten plots and Lineweaver- Burk model evidence from the high coefficient of linear regression (r<sup>2</sup>>0.976). V<sub>max</sub> and K<sub>m</sub> derived from the Lineweaver-Burk model varied from 10.0 to 13.0 μmol/min and 0.5 to 0.9 μM respectively for engineered enzymes and 0.0-10.0 mol/min and 0.0 to 0.9 μM respectively for CNLIN. The kinetics profiles of the studied enzymes showed their actions on cassava linamarin were influenced by degree of genetic manipulation, purification and pH at ambient temperature. The wide pH tolerance in the degradation of linamarin suggests a possible use of the engineered linamarase from <em>Saccharomyces cerevisiae</em> in detoxifying linamarin in cassava for the production of cyanide-free cassava-based food products.
Highlights
Background information: Linamarase (β-glucosidase) is a hydrolytic enzyme
Substrate: Linamarin (100 g) was extracted from about 2kg tubers of the bitter wild cassava (Manihotesculentapohr) variety TSM-TRF-2005035 obtained from Tse-Akaa Village MbalaghMakurdi, Benue State, Nigeria and produced using the method described by Ikediobi and Ogundu (1985): One year old cassava tubers were harvested washed with tap water and promptly frozen overnight at -10°C
Action of Commercial Native Linamarase (CNLIN) on Linamarin was observed only at pH 6.8 whereas GELIN group acted on linamarin at all experimental pH (3.5-10.5) investigated
Summary
Background information: Linamarase (β-glucosidase) is a hydrolytic enzyme. It degrades the glycolytic bond between β-glucose molecule and the chiral carbon atom linked to the nitrile group of linamarin present in cassava. Linamarase (β-glucosidases) is economically very important because of its role as a detoxification agent for improving food safety Even though it can be produced from cassava (Manihotesculenta crantz) tubers the yield of native linamarase from this source is usually too low and expensive such that it is economically unwise to produce the enzyme from cassava tubers (Nok and Ikediobi, 1999). The kinetic data of engineered β-glucosidase on linamarin extracted from cassava will provide insight into the mechanism of action of the enzyme while providing the parameters necessary for predictive purposes. Such predictions which are lacking can be useful tools for fermentation
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
