Hi Mayren. the degradation of lignin in solid lignocellulosic matter by crude extracts is actually very low. You can try a submerged incubation in a shallow layer (cause you need oxygen) arround 50 C, but then it is hard to avoid evaporation. Long incubation times are also needed. The quantification can be performed following the TAPPI methods, but I think the delignification rate will be obscured by the low sensibility of these methods. You will loose more polysaccharides than lignin because your extract will have also hydrolases. It is actually more likely to get a significant delignification of the bagasse with the living microorganism than using only the supernatant.

Thank you very much Fransisco, it is very interesting what you tell me, since I made the experiment using the microorganism and gave good results I just wanted to isolate the laccase and try it, not with the raw extract because what you say is true in the extract there is also presence of cellulase enzymes, I want to test the purified laccase, I found a method called extractable lignin, I do not know if you know it, it's from Aya Fujimoto et al. 2005. and this method estimates the amount of extractable lignin in a dioxane / water mixture at 280 nm and compared to an undegraded pattern. but I wanted to see if someone used another method because I want to prove how good is the laccase produced by the fungus in the degradation of the cell wall of plants.

hello Maryyen

Find the answer bellow. i have given it to a similar question like yours. Feel free to ask me more detail

Laccase activity can be determined by using substrates such as ABTS, catechol,  Syringaldazine and guaiacol. Determination of laccase activity using ABTS can be carried out by dissolving ABTS in 100 mM sodium acetate buffer, pH 5. 

Place a cuvette in the UV spectrophometer and add 3 ml of the prepared substrate. Add little amount of the enzyme from the fermentation broth (Little amount 20-100ul is good to obtain good result because ABTS is highly reactive and the reading changes very fast). Start the stop watch immediately the enzyme is added and take the OD abs at every 1 min interval for 3 to 5 min. calculate laccase activity using change in OD @ 420 nm. ABTS molar extinction coefficient is (ε  = 29,300 /M/cm). Note that one unit of laccase activity is expressed as the amount of laccase required to oxidize 1umol of ABTS per minute