Cellulose is the most abundant polymer in nature. As Leonard Cohen never wrote, "That Old Black [Crone]'s still pickin' cotton for your ribbons and bows." By an old black crone I meant Mother Nature, of course.
The second most abundant polymer is lignin, which is not a polysaccaride at all, but rather a very complicated assembly of three modified alcohol molecules called p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol. (they are actually bonded with a propane like molecule, which doesn't hurt when you are burning wood. And, when lignin is broken down, what do you know, really valuable aromatic stuff comes flying out of this molecule that just prior to breakdown had been literally worth nothing to us (outside of combustion). That's why evolution perked up it's ears when fungus and bacteria came across lignin. It's a pandora's box stuffed with volatile organics that everyone loves.) The damned things are so cleverly bonded, and so complexly mixed up in their construction, that mankind has had a bit of difficulty seeing the white of it's eyes much less cutting it down to size, something rather necessary should we wish to quit our "smoking" (carbon base fuel combustion) habit.
So what is commonly referred to as the holy grail of "cellulosic" alcohol, is actually a bit of a more complicated matter due to considerations that need to be made (and are being made) about the other thirty percent of our Earth biomass: lignin.
I have been interested in lignin for years due to having slowly in my life found it ever more interesting every time I come across it. Sort of like girls. As a very small boy they occupied almost no attention for me at all. But, by and by they gathered more and more significance as my self bumped into theirs. And today I am about halfway toward that point in my late life when I will have finally placed "women/girls" on the pedestal that all old men, almost cartoonishly "learn" to place them. Like I said, sort... of like girls.
So, I discovered lignin when learning stuff in grade school and high school in biology class. Inevitably it was presented as part of a tree, or a part of the wood of a tree or whatever. Not much was said about it because it was presumed to be above our heads to chat much about it's chemistry, ect. It was certainly above the head of much of science to describe what exactly gave lignin it's incredible durability in nature. A fully peer reviewed an rubber stamped scientific model of the molecular structure of lignin remains a bit off. Sections of various different types of lignin have been modeled. I tell you, I am not making it sound as interesting as I should. But wait...
So I went along in life until I was about thirty years old thinking occasionally about a rotten piece of wood in the woods, "boy oh boy, the cellulose in that wood was a nice snack some time ago, but the lignin, is here for the duration of my life." Or something to that effect. Then I read the great Paul Stamets Mycellium Running, after finding it in its appropriate spot at Borders Books. That darn book, even though I had read Aurora's Mushroom's Demystified and really, a bunch of other mycocultural tomes when I was studying while working at Worms Way eleven years ago.... that darn book just hung me upside down and shook. My head banged against the ground a few times, causing some much needed brain damage, and before I knew it I had the beginners mind to start all over again with my consideration of mold, fungus, and the truly delightful mycellium.
I won't go on and on, since I hope to give a better treatment to the delightful fungal world some other time. However, every time I am in my garden, because of Dr. Stamets, I see stuff that were it not so cool it would give me the willlies. Mold growing in every direction beneath the life I live and into the things I love and eat and live within. Most of the time this is regarded as a terrible thing. But common sense is useless in this realm. My garden plants sit like miserable baby's, ignored and failing to thrive, until the mold in my soil pierces their roots with their fungal hyphae. Once that happens, the old memory of evolution and eukaryotic magic enlivens my plants, giving them moisture and sugars, and a life that covers an area so much larger than I ever could have imagined before Dr. Stamets, that yes, I admit, mine is a different perspective entirely.