MICRO 4354 Industrial Microbiology and Biotechnology
Spring 2010
Exam 2
Answer five (5) of the ten questions below. You may use any references you choose, but you must work individually and answer
each question for yourself. This means that you may not discuss these questions with anyone, including people not involved
with this course. Answers are due at the beginning of class, April 19.
1.
W rite two (2) questions (with answers) on any aspect of industrial microbiology. These will be graded subjectively on the
quality of both question and answer. Questions should be conceptual so that answers require thought and insight. Nonconceptual questions will receive no points. It is suggested that you use a variety of sources, although plagiarizing a question
from a textbook will result in a grade of zero (0) for the entire examination. You are encouraged to discuss your questions
with me prior to formulating your answers.
2.
Single-cell protein is going to be produced by growing Pseudomonas 5401 with fuel oil as substrate. The composition of
Pseudomonas 5401 is CH 1.83O 0.55N 0.25. If the final cell concentration is 25 g/L, what is the minimum concentration of
ammonium sulfate ((NH 4) 2SO 4) that must be provided if ammonium sulfate is the sole nitrogen source?
3.
Describe how you could conduct an industrial-scale fermentation under continuous conditions. Feel free to select the type of
fermentation (ethanol, butanol, antibiotic, etc.) as long as it is one that is typically done under batch conditions.
4.
A product called Turbo Yeast is available for home brewers. It consists of freeze-dried yeast cells and a mixture of nutrients.
The claim is that it will ferment a sucrose solution to 14% ethanol overnight or to 20% ethanol within a week. Describe an
experiment or experiments you could use to determine if this remarkable level of productivity is due to the yeast, the
nutrients, or a combination of the two.
5.
Based on what we’ve discussed in lecture and done in lab, how would you design a distillation unit for the large-scale
recovery of ethanol for use as a fuel? Aspects you may want to consider include efficiency, relative costs, product
recovery/purity, or maintenance.
6.
Describe in general terms (e.g., no need for media formulations) a procedure for isolating a proteolytic bacterium and
enhancing the yield of the proteolytic enzyme.
7.
Different factors that could affect the growth of Clostridium butyricum were investigated using a fractional factorial design
(2 8-3) with four center points. The matrix, with results, is available in the file “butyricum ff exam.dx6.” Analyze the data,
determining:
a. W hich factor(s) has(ve) a major influence?
b. Is your model good?
c. Anything else you feel may be significant.
Please include any plots or tables that you feel contribute to your explanations/interpretations.
8.
Select any process in industrial microbiology (except your presentation topic) where the goal is to produce cells or a product
and describe, in broad terms, the major steps. Assume that you’re starting with a pure culture or cultures.
9.
Describe an approach that would use immobilized cells to create a dairy product on an industrial scale. Make sure to explain
why this method would be an improvement over using a non-immobilized system.
10. Early in the semester we performed a simple experiment to estimate growth rates of baker’s yeast. What parameters should
be considered if we were looking for the “best” yeast? Explain how you would select and screen for at least two of the
parameters you identify.