You can oxidize lignin with chemicals or enzymes, that indroduce some functional grups, changing polarity, for instance. You can polymerize lignins and do other reactions. Is there any specific aim that you are looking for?
Thank you so much for your response for my question. Also do you know any specific reaction to modification of lignin with other monomers and improve the polarity .If you know please help me , also do you have publication please send this mail id [email protected]. Anticipating for your favourable reply.