Effect of Temperature, pH, Ionic Strength, and Sodium Nitrate on Activity of LiPs: Implications for Bioremediation

Abstract

The present work is aimed to show the effects of environmental parameters such as temperature, pH, ionic strength, and sodium nitrate on enzyme activity of a LiP Isoenzymes Mixture (LIM) obtained from an immobilized culture of Phanerochaete chrysosporium. LIM enzyme stability was also evaluated. The results are discussed in detail and a comparison with literature data is carried out. LIM showed high activity at pH 3.0 in the temperature range 30 to 40°C, it is able to catalyze oxidation reactions at acid pH (2.5 < pH < 6) and over a wide range of temperatures (25 to 60°C). Ionic strength below 0.2 M had no effect on enzyme activity at pH 4.7 and 39°C. An evaluation of the time decay constant of LIM activity under a specific combination of parameters was also conducted. Finally, an LIM activity and durability map shows the optimal working conditions that might be suitable for its practical application in waste bioremediation processes.

Optimum stability conditions of pH and temperature for ligninase and manganese-dependent peroxidase from Phanerochaete chrysosporium. Application to in vitro decolorization of Poly R-478 by MnP

“…These data are in agreement with those reported recently by Ü rek & Pazarliog˘lu Bosco et al (2002) also found that a mixture of LiP isoenzymes from immobilized cultures of P. chrysosporium catalyzed oxidation reactions at acidic pH and at temperatures between 25 and 60°C.…”

In vitro degradation of carbamazepine and diclofenac by crude lignin peroxidase

“…The decreasing degradation of DFC was in accordance with the inactivation of LiP at higher pH values. It has been previously found that LiP activity was considerably impaired at pH values over 4.5 [15,16]. The repressed degradation of DFC at pH 2.5 was probably due to the instability of LiP at such a low pH value [16].…”

Optimization of lignin peroxidase production and stability by Phanerochaete chrysosporium using sewage-treatment-plant sludge as substrate in a stirred-tank bioreactor

“…[23], and Irpex lacteus [24] have been reported to produce ligninolytic enzymes. Among the fungi tested for the ligninolytic system, the most common white rot fungus is P. chrysosporium, which can selectively degrade lignin and xenobiotic compounds [25][26][27][28][29]. P. chrysosporium produces ligninolytic enzymes that are widely used in the removal of dyes from industrial effluents [22], bio-bleaching [23], and treating hazardous waste [30].…”

“…The common bioreactors used in scaling-up the production of ligninolytic enzymes are submerged stirredtank reactors [15], modified reactors with nylon-web carriers or a polyurethane system for the fungus [31,32], hollow fiber reactors, silicone membrane reactors [30], packed-bed bioreactors [16], and trickle fixed-bed reactors [27]. The present study was carried out to identify the optimum operating conditions of the stirred-tank bioreactor for yielding maximum LiP activity using STP sludge as a substrate by statistical approach.…”