ИСТИНА

Spectral properties of fungal metabolites in liquid medium were measured and compared with that for natural humus substances (HS) and commercial humate preparation in water. Chromophoric organic matter released by various fungi strains showed absorption and fluorescence spectra similar in main spectral features for samples with different pigmentation of mycelium: decreasing absorbance values towards longer wavelengths with a shoulder at 280-290 nm and fluorescence emission spectra with two overlapping bands (UV fluorescence of phenolics and proteins within 300-350 nm and blue fluorescence of fungal polymers). After two weeks of cultures growing in liquid humate solution its fluorescence characteristics became more similar to that of HS in natural water. Wavelength of emission maximum and quantum yield of humic-type fluorescence band were found to be excitation wavelength dependent because of increased heterogeneity of HS in culture medium compared to initial commercial humate solution. Transformations in HS composition caused by microscopic fungi can be monitored and characterized using spectral measurements.