Now showing 1 - 2 of 2
  • Publication
    Isolation and characterization of laccase secreting microorganism from Gua Kelam 2, Perlis
    (AIP Publishing, 2023)
    Natasha Yasmin Hasnol Azahari
    ;
    Nor Anis Syafiqah Suhaily
    ;
    Sandrasekaran Naresh
    ;
    ;
    The current study, involves isolation and characterization of laccase producing microbes from Gua Kelam 2, Perlis, Malaysia. In our study, all isolates were cultivated on nutrient agar containing guaiacol. Only one isolate (GK1) was detected as a positive laccase producer which was then subjected for growth curve and kinetic analysis using nutrient broth and minimal salt medium. For nutrient broth, short exponential phase was recorded from 2nd h until 4th h in contrast to minimal salt medium that exhibited exponential phase from 8th h until 24th h. The highest laccase activity was recorded in nutrient broth (4.50 U L-1) at 4th h incubation compared to minimal salt medium (3.72 U L-1) at 30 h. The isolate GK1, was characterized to be rod shape and Gram positive bacterium. Based on the 16S rRNA sequencing, the isolate determined to be Bacillus subtilis.
  • Publication
    Functionalization 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 Shuit
    ;
    In 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.