The giant panda is one of the most endangered animals in the world, with only 2,500 to 3,000 individuals found in western China. Approximately 7 million years ago, the ancient giant panda was omnivorous, but it shifted from being an omnivore to a herbivore after 4.6 million years to 5 million years of evolution, with soft bamboo shoots, stems, and leaves comprising 99% of its diet. The modern giant panda retains a gastrointestinal tract typical of its carnivorous ancestry. Analysis of the giant panda genome revealed that it encodes all the enzymes necessary for a carnivorous digestive system but lacks those for digesting lignocellulose, the principal component of its bamboo diet. Microbes in the giant panda intestines help it digest cellulose and hemicellulose. So do they also help it digest lignin? Why, yes they do.
(2012) Evidence for Lignin Oxidation by the Giant Panda Fecal Microbiome. PLoS ONE 7(11): e50312. doi:10.1371/journal.pone.0050312 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0050312