Poly(ethylene glycol)-modified ligninase enhances pentachlorophenol biodegradation in water-solvent mixtures

Abstract

Polychlorinated hydrocarbons are prevalent environmental contaminants whose rates of biodegradation are limited by their minimal solubilities in aqueous solutions where the biological reactions take place. In this study, ligninase (LiP) from Phanerochaete chrysosporium was modified by poly(ethylene glycol) to enhance its activity and stability for the biodegradation of pentachlorophenol (PCP) in the presence of acetonitrile (MeCN), a water-miscible solvent. The modified enzyme retained 100% of its activity in aqueous solutions and showed enhanced tolerance against the organic solvent. The activity of the modified enzyme was found to be over twice that of the native enzyme in the presence of 10% (v/v) MeCN. The solubility of PCP was enhanced significantly by the addition of MeCN to aqueous solutions, such that it was over 10-fold more soluble in the presence of 15% (v/v) MeCN than in pure aqueous buffer solution (from 0.06 to 0.65 mM). Capitalizing on the enhanced substrate solubility and the increased activity of the modified enzyme, the catalytic efficiency of the modified LiP in solutions containing 15% MeCN was over 11fold higher than that of the native enzyme in buffer solutions (pH 4.2) in unoptimized reactor systems (from 44 to 480 mol PCP/mol LiPиh). Continued research both in the use of organic solvents to increase the availability of recalcitrant contaminants and in the modification of enzymes to enhance their activity and stability in such solvents promises to dramatically affect our ability to remediate contaminated sites. Published by John Wiley & Sons

Enzyme‐Carrying Polymeric Nanofibers Prepared via Electrospinning for Use as Unique Biocatalysts

“…In many cases, however, low catalytic efficiency and stability of enzymes have been seen as barriers for the development of largescale operations to compete with traditional chemical processes (1)(2)(3)(4)(5)(6). Methodologies such as genetic and protein engineering (7-10), evolution (11,12), solvent engineering (2,(13)(14)(15), and chemical modification (16)(17)(18)(19)(20)(21) are among the most actively investigated strategies to improve the functionality and performance of enzymes for bioprocessing applications.…”

Heterologous Expression of Phanerochaete chrysoporium Glyoxal Oxidase and its Application for the Coupled Reaction with Manganese Peroxidase to Decolorize Malachite Green

“…Compared with intact cells of P. chrysosporium , degradation of lignin or organopollutants using lignin degrading enzymes, such as LiP, MnP, and laccase (phenol oxdiase), has some advantages, including no nutrient supply and easy control of temperature and pH [12], however, this enzymatic degradation is influenced by the H 2 O 2 supply strategy. At the beginning of the reaction, activity of Lip or MnP is inhibited by excess H 2 O 2 .…”

Self-Assembling of Polymer-Enzyme Conjugates at Oil/Water Interfaces

“…MALDI-TOF analyses of the conjugate samples unfortunately failed to reveal the molar mass of the conjugate. Conversely, MALDI-TOF analyses of CT conjugated with an amphiphilic modifier, PEG (M w 5000), indicated that one or two attachments were achieved (10). Since the conjugate of PS (water insoluble) in the current work involved a much weaker reaction as compared to that of PEG (water soluble), we believed that the majority of conjugate should only have one PS chemically attached to each CT molecule.…”