Laccases are a group of copper-containing phenoloxidases, which activity can stimulated by copper ions. The conditions of obtaining, isolation and purification of extracellular laccase of the basidiomycete Fomes fomentarius VKPM F-1531 were studied. The optimal concentration of copper in the glucose-peptone nutrient medium and duration of the surface-liquid cultivation for the highest yield of the enzyme were established. The efficient synthesis of fungal laccase by the fungus F. fomentarius VKPM F-1531 requires the optimal concentration of copper in the nutrient medium of 200 mg/l. The highest enzyme activity was achieved on the 14th day of surface-liquid cultivation on glucose-peptone nutrient medium with optimal CuSO4 supplementation and it was more than 6–6.5 times higher than the one obtained on the conventional glucose-peptone medium. The protein fraction that precipitated in the range from 50% to 70% saturation had a laccase activity for 40 times higher than the initial activity in the culture liquid. The molecular weight of the purified laccase determined by the SDS-PAGE was about 60 kDa.

This work presents a detailed study on the effect of various functional groups both at the ortho position of the aromatic ring and in the amino group of PANI on the antibacterial properties of polymers against gram-positive (Bacillus subtilis) and gram-negative (Pseudomonas aureofaciens) microorganisms. It was found that incorporation of methyl, methoxy, or pentyl groups into the ortho-position of PANI did not increase the antibacterial activity but in most cases causes a significant decrease in the antibacterial properties of functionally substituted polyanilines. At the same time, PANI derivatives modified by incorporation of pentyl groups into the amino group were found to be more efficient antibacterial compounds against both gram-positive and gram-negative microorganisms than the original polymer. It was also found that N-substituted PANI derivatives manifest not only bactericidal but also bacteriostatic properties toward the test microorganisms. Varying the nature and position of the substituent allowed us to conclude that the synthesis of various N-substituted PANI derivatives with a high degree of doping is the most promising approach to PANI modification for application in bacterial growth inhibition.