Deinking of Wastepapers with White-rot Fungus, <i>Phanerochaet chrysosporium </i>NRRL 6361

Abstract

The study examines the ability of white-rot fungus <i>Phanerochaet chrysosporium </i>NRRL 6361 to deink the wastepapers under investigation; namely, newsprint, writing, and printing papers. The wastepapers are inoculated with culture of <i>P.</i> <i>chrysosporium </i>NRRL 6361 under sterilized conditions at different pHs (5-11.4) in the presence and absence of growth media. The optimization of the process parameters shows that the incubation for one week at 32 ± 2°C results in maximum deinking of recycled newsprint at pH 11.4 with brigtness 39 per cent and maximum brightness of recycled printing papers 75 per cent at pH 7.2, while for writing paper the maximum brightness obtained is 80 per cent at pH 7.5. The α-cellulose content

of recycled wastepapers is found to increases, while lignin decreases during deinking by <i>P. chrysosporium </i>NRRL 6361. The results indicate that the fungus do not have any affect on the cellulose. Scanning electron microscope (SEM) is used to follow the fungus growth hyphae through the wastepapers after one week of incubation. The mechanical properties of the handsheets made from recycled wastepapers slightly decrease. Therefore, starch-silicate complex is used to overcome the decrease of the mechanical properties.