Physiological Regulation of an Alkaline-Resistant Laccase Produced by Perenniporia tephropora and Efficiency in Biotreatment of Pulp Mill Effluent.
10.5941/MYCO.2016.44.4.260
- Author:
Churapa TEERAPATSAKUL
1
;
Lerluck CHITRADON
Author Information
1. Department of Microbiology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand. fscillc@ku.ac.th
- Publication Type:Original Article
- Keywords:
Laccase;
Perenniporia tephropora;
Physiology;
Pulp mill effluent;
White-rot fungi
- MeSH:
Biological Oxygen Demand Analysis;
Biomass;
Carbon;
Copper;
Copper Sulfate;
Fungi;
Glucose;
Hydrogen-Ion Concentration;
Ions;
Laccase*;
Lactose;
Physiology
- From:Mycobiology
2016;44(4):260-268
- CountryRepublic of Korea
- Language:English
-
Abstract:
Regulation of alkaline-resistant laccase from Perenniporia tephropora KU-Alk4 was proved to be controlled by several factors. One important factor was the initial pH, which drove the fungus to produce different kinds of ligninolytic enzymes. P. tephropora KU-Alk4 could grow at pH 4.5, 7.0, and 8.0. The fungus produced laccase and MnP at pH 7.0, but only laccase at pH 8.0. The specific activity of laccase in the pH 8.0 culture was higher than that in the pH 7.0 culture. At pH 8.0, glucose was the best carbon source for laccase production but growth was better with lactose. Low concentrations of glucose at 0.1% to 1.0% enhanced laccase production, while concentrations over 1% gave contradictory results. Veratryl alcohol induced the production of laccase. A trace concentration of copper ions was required for laccase production. Biomass increased with an increasing rate of aeration of shaking flasks from 100 to 140 rpm; however, shaking at over 120 rpm decreased laccase quantity. Highest amount of laccase produced by KU-Alk4, 360 U/mL, was at pH 8.0 with 1% glucose and 0.2 mM copper sulfate, unshaken for the first 3 days, followed by addition of 0.85 mM veratryl alcohol and shaking at 120 rpm. The crude enzyme was significantly stable in alkaline pH 8.0~10.0 for 24 hr. After treating the pulp mill effluent with the KU-Alk4 system for 3 days, pH decreased from 9.6 to 6.8, with reduction of color and chemical oxygen demand at 83.2% and 81%, respectively. Laccase was detectable during the biotreatment process.
