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Kunasundari Balakrishnan
Preferred name
Kunasundari Balakrishnan
Official Name
Balakrishnan, Kunasundari
Alternative Name
Balakrishnan, K.
Kunasundari, B.
Kunasundari, Balakrishnan
Main Affiliation
Scopus Author ID
37861493500
Researcher ID
DBC-0761-2022
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1 - 2 of 2
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PublicationFunctionalization of Multiwall Carbon Nanotubes (MWCNTS) using Phosphoric acid for immobilization of cellulase(United Scientific Group, 2023)
;Hasnol Azahari Natasha Yasmin ;Thivagar Rao ;Sandrasekaran Naresh ;Siew Hoong ShuitIn this paper, functionalization of multiwall carbon nanotubes (MWCNTs) using phosphoric acid (H3 PO4 ) was attempted. Based on the One Factor at a Time (OFAT) analysis, 8 M of H3 PO4, 8 h of reflux time and 80 °C were identi-fied as an ideal condition for the acid oxidation process. Successful functionaliza-tion of MWCNTs using H3 PO4 was revealed from Fourier Transform Infrared Spectroscopy (FTIR) peaks and Scanning Electron Microscope (SEM) images. The resulting f-MWCNTs were immobilized with cellulase via adsorption. The optimum temperature for free cellulase was at 50 °C and for immobilized cel-lulase was at 60 °C. The optimum pH was at 5 for both free and immobilized cellulase. Higher thermal stability was achieved with immobilized cellulase in which 39% activity still was retained at 80 °C compared to free cellulase. Reus-ability study of immobilized cellulase depicted 28% of remaining activity after 5th cycle of analysis using model substrate (filter paper Whatman No. 1). These results suggest that H3 PO4 which is a mild acid is a promising substitution for functionalization of MWCNTs. -
PublicationPaddy straw saccharification using immobilized laccase on magnetized multiwall carbon nanotubes(Springer, 2024-05)
;Hasnol Azahari Natasha Yasmin ; ;Siew Hoong Shuithe effective recovery of the immobilized enzymes using magnetic carriers has led to growing interest in this technology. The objective of this research was to evaluate the efficiency of immobilized laccase on magnetized multiwall carbon nanotubes (m-MWCNTs) in terms of stability and reusability. Laccases were efficiently adsorbed onto magnetized multiwall carbon nanotubes (m-MWCNTs) synthesized using water. The concentration of 7 mg laccase/mL was found to be ideal for immobilization. The optimal activity of both free and immobilized laccases was observed at pH 5, while for the latter, the optimal temperature was shifted from 40 to 50 °C. Compared to the free laccase, the immobilized laccase exhibited a greater range of stability at more extreme temperatures. At the fourth cycle of reactions, the immobilized laccase exhibited more than 60% relative activity in terms of reusability. Based on the fourier-transform infrared spectroscopy (FTIR) peak at 2921 cm−1, saccharification of paddy straw using immobilized laccase verified lignin degradation. The easy recovery of the immobilized laccase on m-MWCNTs lends credence to its potential use in biomass hydrolysis.