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Option B.1- Understandings, Applications and Skills
Essential Idea - Modified Microorganisms used in
Industrial Processes
Why?
● They are small - single-celled, like bacteria and yeast
● They reproduce rapidly - bacteria divide by fission every 30
minutes
● As a group, they have very diverse metabolisms - (see next four
slides)
If you start with 100 cells at time 0,
how many cells will you have in 30 min?
60 min? 90 min?
Photoautotroph - photosynthetic bacteria
Use sunlight for
energy and CO2
for carbon source
(can “fix” free C into
bonded C - by the
process of photosynthesis)
Photoheterotroph - Purple Bacteria
Uses sunlight for energy and organic*
compounds for carbon source
* organic compounds defined as?
Chemoautotroph - Sulfur Bacteria, Nitrogen-fixing
Bacteria
Use inorganic* compounds, like H2S, for energy (chemosynthesis) and CO2 as
carbon source
* inorganic compounds
defined as?
Chemoheterotrophs - fungi, protozoa, bacteria
Use organic molecules from biotic sources
for energy as well as for a carbon source
how does this
fungus on an
orange
challenge the
idea of
“microscopic”?
time lapse videos - Winogradsky Panels
Products made from microorganisms
How are these different from foods made
by plants or animals?
Pathway Engineering
What are some natural biochemical pathways we have studied already?
In pathway, or metabolic engineering, internal genetic or regulatory processes
are controlled to increase the production of a particular chemical from the cell.
Kechun Zhang, Univ Minn
Metabolites of Interest
an example:
why bacteria
and yeast?
what else has
been made?
Better source for malaria drug, Artemisinic Acid
What had previously only been available from wormwood plants, via an unstable
and lengthy process can now be made in one-fifth the time in yeast. The enzymes
in the pathway below are from plant genes, moved into yeast.
Large Scale Fermentation*
What kind of probes?
Why? - to maintain optimal conditions for growth
* how is fermentation related to respiration?
Deep tank fermentation
of Penicillium
Penicillium mold only makes penicillin
when the fungus is stressed/starved.
This is called a secondary metabolite.
Because of this, a starter culture has
to be grown, initially with glucose*, and
then the culture is moved to the batch
culture without glucose and the mold
makes the secondary metabolite for
survival.
*what is the primary metabolite, the
product of glycolysis?
also provided by fermenter:
pH 6.5 by NaOH
cooling water jacket
oxygen (aerobic process)
Production of Citric Acid - continuous culture
Previously extracted from citrus fruit, which
became less available during WWI. A new
source was discovered soon after that with
the fungus Aspergillus niger and molasses
as a carbon source. A continuous culture
allows a steady state of growth and higher
production of citric acid.
Biogas production by archeans* and bacteria
No sun? No wind? No problem.
A series of
processes are involved:
Because the methanogen in anaerobic
Added benefits - high quality odorless, weedless
fertilizer is a by-product and consumption of
methane reduces greenhouse gas levels
*what feature of the archaeabacteria separates them from the eubacteria?
Gram Staining of Bacteria
A method identifying different classes of bacteria
A method identifying different
classes of bacteria, based on
the structure of their cell walls.
Those bacteria with an extra
layer of lipid do not stain positive
and are often toxic to their hosts.