Analysis of the biosolubilisation product
Bartosz Strzelecki, Natalia Kwiatos, Irena Romanowska, Hanna Miszkiewicz, Stanisław Bielecki
Keywords: biosolubilisation, brown coal, fungi
equipment required: tube 20ml, pipette (10, 1 and 0,2 ml), spectrophotometer UV-VIS, quartz
cuvette, spectrophotometer FT-IR, pH-meter, thermostat,
Description: Black supernatants obtained in biosolubilisation process are characterized by
UV-Vis spectroscopy, infrared spectroscopy (FTIR), elementary analysis and pH
measurements.
UV – Vis spectroscopy (T80+ UV/VIS PG Instruments Ltd) is used to estimate amount of
humic and fulvic acids (450 and 650 nm) released during the process. A standard curve was
prepared for humic acids from polish brown coal as described by Dong et al. To determine
the biosolubilisation degree the following formulas were used:
 Amount of humic acids:
  A450  dillution  V

1000
Where:
X – mass of obtained humic acids [mg]
 1 
Y – a factor obtained from the calibration curve: 

 g  ml 
A450 – absorbance at 450 nm – characteristic for humic acids
V – volume of the obtained product [ml]
1000 – multiplication factor to convert μg to mg of humic acids.
 Biosolubilisation degree:
Mh
 100%
MC
Mh – mass of obtained humic acid [g]
Mc – initial mass of coal added to culture [g].
Additionally, spectra in range of 600 – 200 nm are recorded for all collected samples.
The soluble products are lyophilized and tested by Nicolet 6700 FT-IR, Thermo Scientific,
with light wavelengths from 4000 cm-1 to 500 cm-1 Polish lignite and products of
biosolubilisation is also analyzed in terms of the elemental composition (C, H, O, N and S) by
EuroVector 3018 analyzer.
pH measurement is performed for sterile medium, inoculum and obtained products during
biosolubilisation process .
Dong L., Yuan Q., Yuan H. (2006), “Changes of chemical properties of humic acids from
crudeand fungal transformed lignite”, Fuel 85, 2402 – 2407