title: Solvent Stability Study with Thermodynamic Analysis and Superior Biocatalytic Activity of Burkholderia cepacia Lipase Immobilized on Biocompatible Hybrid Matrix of Poly(vinyl alcohol) and Hypromellose.
abstract: In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (K(D)) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the K(D)-value was found to be less in cyclohexane (0.843 × 10(-3)) as compared to acetone (1.997 × 10(-3)), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (E(a)) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic efficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH(⧧)), entropy (ΔS(⧧)) and Gibb's free energy (ΔG(⧧)) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time.
authors.affiliation: Department of Chemistry, Institute of Chemical Technology , Mumbai-400 019, India.
authors.forename: Kirtikumar C
authors.initials: KC
authors.lastname: Badgujar
authors.affiliation: Department of Chemistry, Institute of Chemical Technology , Mumbai-400 019, India.
authors.forename: Bhalchandra M
authors.initials: BM
authors.lastname: Bhanage
mesh_terms: D055162:Biocatalysis; D001672:Biocompatible Materials; D016956:Burkholderia cepacia / Q000201:enzymology*; D004800:Enzymes, Immobilized / Q000378:metabolism*; D006207:Half-Life; D065347:Hypromellose Derivatives / Q000737:chemistry*; D007700:Kinetics; D008049:Lipase / Q000378:metabolism*; D011142:Polyvinyl Alcohol / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D001672:Biocompatible Materials; D004800:Enzymes, Immobilized; D012997:Solvents; D065347:Hypromellose Derivatives; D011142:Polyvinyl Alcohol; D008049:Lipase