Three-phase partitioning and immobilization of <i>Bacillus</i> <i>methylotrophicus</i> Y37 cellulase on organo-bentonite and its kinetic and thermodynamic properties

DUMAN Y., KAYA A. U., YAĞCI Ç.

CLAY MINERALS, vol.55, no.2, pp.120-131, 2020 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 55 Issue: 2
  • Publication Date: 2020
  • Doi Number: 10.1180/clm.2020.18
  • Journal Name: CLAY MINERALS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Agricultural & Environmental Science Database, Aquatic Science & Fisheries Abstracts (ASFA), CAB Abstracts, Chemical Abstracts Core, Communication Abstracts, Compendex, Geobase, INSPEC, Metadex, Civil Engineering Abstracts
  • Page Numbers: pp.120-131
  • Kocaeli University Affiliated: Yes

Abstract

In this study, for the first time Bacillus methylotrophicus Y37 cellulase was purified and recovered in a single step by three-phase partitioning (TPP). The optimal purification parameters for TPP were 40% ammonium sulfate saturation (m/v) with a 1.0:1.0 (v/v) ratio of crude extract:t-butanol, which gave 5.8-fold purification with 155% recovery of cellulase. Non-covalent immobilization of the partitioned cellulase was performed using bentonite as a support material. The activity observed in the 20th experiment was 100%. The optimal pH values and temperatures determined for the free enzyme and the immobilized enzyme were 5.0 and 6.0 and 45 degrees C and 50 degrees C, respectively. The Arrhenius activation energy (E-a) of the immobilized enzyme was lower than that of the free enzyme, whereas the Michaelis-Menten constant (K-m) and maximum velocity (V-m) of the immobilized enzyme increased. The turnover number (k(cat)) and the catalytic performance (k(cat)/K-m) demonstrated the improved catalytic properties of the immobilized enzyme compared to the free enzyme. Immobilization of cellulase is thermodynamically preferred.