Analysis of malt extract growth medium incubated with Pleurotus ostreatus strain by capillary zone electrophoresis and photometric methods

Abstract

Polycyclic aromatic hydrocarbons (PAHs) form high proportion of creosote, which are used to impregnate wooden railway sleepers. Some of PAHs are potential carcinogens. Some strains of white root fungi are known to produce non – specific extracellular enzymes, which are capable of degrading PAHs. One of those enzymes is laccase. The aim of this research was to develop an optimized capillary zone electrophoresis (CZE) analysis method and photometric analysis method for determination of the activity of laccase enzyme in growth medium. 0,5 M acetic acid was used as background electrolyte, separation voltage – 7.4 kV, sample injection – 20 kPa * 40 sec, analysis duration – 45 minutes, detector type – contactless conductivity detector, 50 μm inner diameter, coated silica capillary was used for the separation. To determine enzymatic activity of laccase, photometric analyses were conducted at 415 nm wavelength, 50 μl of malt extract grown medium, containing P. Ostreatus was diluted with 1350 μl sodium acetate buffer (pH – 4.5), 100 μl of 30 mM ABTS solution was added to the reaction mixture as substrate for enzymatic reaction. The highest enzymatic activity (0.00236 IU/ml) was determined after six days of P. Ostreatus incubation in malt extract growth medium. CZE analysis results showed highest growth medium changes during incubation period of 6 days.