DEGRADATION OF NATURAL LIGNINS AND LIGNOCELLULOSIC SUBSTRATES BY SOIL-INHABITING FUNGI IMPERFECTI

The most powerful lignin-degraders among the 82 microbial strains isol ated during a screening of ligninolytic microorganisms from forest soi l were identified as Penicillium chrysogenum, Fusarium oxysporum and F usarium solani. These fungi imperfecti mineralized 27.4%, 23.5% and 22 .6% of C-14-labelled milled wood lignin (MWL) from wheat straw after 2 8 days of incubation in liquid media. Degradation of MWL from pine by P. chrysogenum was 8% and 19% when it was evaluated by spectrophotomet ry and Klason Lignin, respectively, but this substrate was hardly mine ralized. All fungi were able to attack the hemicellulosic, cellulosic and also lignin fractions of wheat straw during solid-state fermentati on, F. solani being capable of degrading about 25% of both carbohydrat es and lignin. When the selected fungi were tested for dye decolouriza tion, they all readily attacked the polymeric dye Remazol brilliant bl ue R (RBBR) and also poly R-478 to a minor extent.