This part is about fermentation or
anaerobic respiration, and I really don't
know whether to put it in the
biochemical part or leave it in the
fungal part, because it becomes very
important when we start looking at what
we do with fungi. How fungi work, and it
also goes back to working how we deal
with bacteria and some of the stuff we
get out of bacteria. When we look at
glycolysis, glycolysis ends up in pyruvic
acid. Out of pyruvic acid, it's a three
carbon unit that has got to be dealt
with in some way or another. When we
created the pyruvic acid, what we did was
we used up 2 ATP. In the end we made
4 ATP and we made 4 NADH. Normally
this goes through the Krebs cycle. It
goes to acetylCo-A, goes through the
Krebs cycle, and down that way. But if the
Krebs cycle backs up, because the
electron transport system backs up,
because there's no oxygen, then we have
to have some sort of alternative pathway.
And that's what this unit is about. It's
about that alternative pathway that we
call fermentation. In this there are a
couple of different ways that this can
go. One is the enzyme lactase
dehydrogenase comes in, uses up an NADH.
In order to do this, and this is one of
the two we had that was made, so out of
every glucose we're gonna use up 2
NADH. And out of the lactate
dehydrogenase, we create lactic acid. Now
lactic acid builds up in animal tissue,
and it becomes quite problematic because
out of that that you get cramps and
things like that. So it's not a good
material to have built up. Eventually
it's going to get excreted but what we
really aren't getting out of this, is we
aren't getting any energy. All we've got
are the two extra ATP's.
But we don't have any NADH. The other
pathway we can go through is a pathway
where pyruvate gets decarboxylated using
pyruvate decarboxylase, drives off a
carbon dioxide, and as we get that we get
a material called acetyl aldehyde. And
then the acetyl aldehyde can be
transformed into 
other things. It says if you take the
alcohol dehydrogenase in here it will
turn it into ethanol. So all of a sudden
we've got ethanol, which can be a useful
product, but again we used up that NADH.
So we have virtually nothing in the end
as far as energy, but ethanol is produced
by bacteria and fungi. And it's not
necessarily something that we want to
have build up, because it itself will
become toxic as well. So in the concept
of fermentation or anaerobic respiration
we have the conversion of pyruvate into
one of two materials depending on the
type of system we've got. When this
happens we often get fermentation. This
is a barrel where they were fermenting
grape juice, and you can see the little
fermentation bubbler up on the top. If
you looked at it, it was producing carbon
dioxide which was being released off and
it was bubbling up through this little
tube. So we can use this and we can make
industrial products with it. 
There are a lot of different things. You
know fermentation products. One of the
fermentation products and get this
alcohol in this particular case. You're
looking at some grapes. We harvest the
grapes, we crush the grapes up, we put
them in the barrel. After a certain
period of time, by a very skillful hand,
it turns into a bottle of wine or
something along those lines.
These are bottles of champagne that are
being aged. To have the proper culture of
champagne in it and then what they will
do is they will actually take these
bottles and they will remove the
material that filters out of it. You take
all of that, you make this real nice area
where you can sell all this wine, but
wine isn't the only fermentation product
we have out of alcohol. As college
students, you understand beer, and there's
a lot of different kinds of beers. 
Some people like some beers better than
others. I've been in stores that probably
have 500 different kinds of beer and I'm
not sure if I'd call it all beer. You
know, considering that one of it was made
out of pumpkin! So you look at that the
other thing we can do with alcohol is we
can distill it. And as you distill it you
get what we would call a type of spirit.
This is a very pretty bottle of gin that
is made in South America, and it's an
absolutely gorgeous bottle. 
It's phenomenal material that comes out
of it and it's an alcohol type product.
There are other types of fermentation
products. We get this is household type
products. Household type products include
vinegar, that comes out of a fermentation
product ,where the organism makes acetic
acid. We often get this by taking things
like old fruits. Old apples that you know
that don't make it, they turn into
vinegar. Wine itself will turn into
vinegar if not properly cared for.
We could have a fermentation product
like yogurt, and in yogurt we use
bacteria in order to be able to ferment
this into this very interesting product.
Here's one called nail polish remover.
Acetone comes out of a certain type of
bacterium. Not that you want to consume
this, but it is made from microorganisms.
Rubbing alcohol comes out of a
fermentation product. Again, so we look
at fermentation and that becomes very
very interesting.
Here's a totally different format of
fermentation, and this is a fermentation
where they were making a hard cheese.
This is a parmesan type cheese only it's
it was absolutely exquisite. They were
aging this stuff for about four years on
the shelf. Material was, you know, is
phenomenally good and again this happens
with the fermentation product. This one
is a slow process where they've got
certain microorganisms on the inside and
it allows to equilibrate and do things
very very interestingly. So when we look
at fermentation, fermentation is a
process by which we create products
because glycolysis couldn't go through
the Krebs cycle but rather it had to go
in an alternative pathway.
