By incubating bacteria from the gut of the termite, Nasutitermes takasagoensis, in a culture medium containing a ligninic compound, direct evidence that lignin-biodegradation occurs in the gut of termites was obtained. The bacteria were capable of degrading ligninic compounds. 28% of dealkalized lignin was degraded and lignin dimer compounds, which have a linkage proper to lignin, such as beta-O-4, beta-1, phenylcoumarane and biphenyl bonds, were degraded by 60 % to 95 %.