Effect of soya lecithin on the enzymatic system of the white-rot fungi Anthracophyllum discolor

Abstract

The present work optimized the initial pH of the medium and the incubation temperature for ligninolytic enzymes produced by the white-rot fungus Anthracophyllum discolor. Additionally, the effect of soya lecithin on mycelial growth and the production of ligninolytic enzymes in static batch cultures were evaluated. The critical micelle concentration of soya lecithin was also studied by conductivity. The effects of the initial pH (3, 4, and 5) and incubation temperature (20, 25, and 30°C) on different enzymatic activities revealed that the optimum conditions to maximize ligninolytic activity were 26°C and pH 5.5 for laccase and manganese peroxidase (MnP) and 30°C and pH 5.5 for manganese-independent peroxidase (MiP). Under these culture conditions, the maximum enzyme production was 10.16, 484.46, and 112.50 U L(-1) for laccase, MnP, and manganese-independent peroxidase MiP, respectively. During the study of the effect of soya lecithin on A. discolor, we found that the increase in soya lecithin concentration from 0 to 10 g L(-1) caused an increase in mycelial growth. On the other hand, in the presence of soya lecithin, A. discolor produced mainly MnP, which reached a maximum concentration of 30.64 ± 4.61 U L(-1) after 25 days of incubation with 1 g L(-1) of the surfactant. The other enzymes were produced but to a lesser extent. The enzymatic activity of A. discolor was decreased when Tween 80 was used as a surfactant. The critical micelle concentration of soya lecithin calculated in our study was 0.61 g L(-1).

Effect of Soya Lecithin on Solubilization and Biodegradation of Pentachlorophenol by <i>Anthracophyllum discolor</i>

“…The result shows that SL had certain effect on the solubilization of PCP either below or above its CMC, 0.61 g•L −1 [30]; the solubilization was higher than when the SL concentration was above its CMC. Similar result was reported by Eddouaouda et al [34].…”

“…Information about the effect of SL on degrading microorganisms is limited. However, Bustamante et al [30] found that the increase in SL concentration caused an increase in mycelia growth of A. discolor. Besides, Soeder et al [25] found that SL enhanced growth of the bacteria under all conditions evaluated of surfactant concentrations.…”

“…Besides, it depended on contaminant and P. aeruginosa strains. [30]. However, the CMC of surfactant depends on many factors, such as determination method [38,39], phospholipid composition, electrolyte addition, solution temperature, presence of organic additives [40] or conditions of salinity [41], among other; making this value different from the one determined in pure water [39].…”

“…Soeder et al [25] established that SL enhances growth of bacteria. Besides, Bustamante et al [30] demonstrated that when SL is included in the growth medium, it enhances growth and MnP production of A. discolor. In this context, scanning electron microscopy (SEM) is a useful tool for exploring the surface of microorganisms and detecting the biosurfactant effect.…”

Isolation of laccase gene from Bacillus subtilis and analysis of its physicochemical properties

“…At present, laccase is obtained from organisms such as fungi. However, the low growth rates of these organisms and the low activity of these naturally derived cannot meet the market demand (Bustamante et al, 2011;Cañas and Camarero, 2010). In recent years, more attention has been focused on recombinant laccase (Ranieri et al, 2009), the yield of recombinant laccase, which could be increased significantly.…”