BIOE6028 Project 2023
Project Report: 40 marks
Waste gas streams rich in carbon monoxide (CO) can be valorised by fermentation
to chemicals and other products. In this project you will need to valorise a gas
stream of CO as 2,3 Butanediol (2,3 BDO). You will be responsible for the following
tasks: 1) build a stoichiometric model of 2,3BDO production using the simplified
metabolic network of the Wood-Ljungdahl pathway that has been provided, 2)
expand the model by incorporating the Rnf complex into the model, 3) design a way
to increase 2,3 BDO production through genetic alterations of the cells, 4) add the
Wood-Ljungdahl pathway to a mutant strain of E coli and compare your results to
parts 1-3, 5) optimise the volumetric productivity of 2,3 BDO through assessing ways
to balance cell growth with product formation in 1 vs 2-stage processes. Your
individual project report will have a maximum of 15 pages, and you will need to
submit an Excel file showing your flux balance analysis and other calculations. This
work will be presented to the teaching team at the end of the course.
Project abstract (1 pg max) – 4 marks: The abstract should consist of an overview
of your project, including the main idea of the work, key results and conclusions.
Ideally, the overview should be understood by both experts and professionals with
different backgrounds (non-bioengineering). Visual tools such as a cartoon or
diagram should accompany your abstract to illustrate the main ideas.
Introduction (1 pg max) – 4 marks: An introduction to your report should present
key background information about 2,3 BDO production and its uses in industry,
based on a literature review, citing multiple references. Having a brief, well-written
introduction is a huge help to anyone interested in reading about your project.
Model-based evaluation:
Describe your procedures in performing each task, stating any assumptions made,
and showing and discussing your results in the report.
A) In Excel, build a stoichiometric model for 2,3 BDO production via the Wood_x005f Ljungdahl pathway. A list of reactions has been provided to you in Excel.
Before re-designing this strain, what is the 2,3 BDO yield that can be achieved
from 1 mol/h of CO feeding 4 marks
B) Based on Westphal et al. (https://doi.org/10.1128/JB.00357-18), add the
Hydrogenase into the model as described here, where hydrogen can be
considered as an additional input. Examine the 2,3 BDO yield with a similar 1
mol/h CO feeding rate to ensure a consistent comparison. Compare the
model predicted fluxes with your previous evaluation, justifying the rationale
for why fluxes are estimated to be the same or different. 4 marks
C) Perform strain design to maximise 2,3 BDO production using the model from
part B. Simulate the process with a 1 mol/h CO feeding rate and compare the
product yields obtained. Critically discuss the reason for improvements in 2,3
BDO yield. 4 marks
D) Based on the E. coli model supplied in class, add 2,3 BDO production through
the Wood-Ljungdahl pathway to the E. coli model. Discuss how the mutant
strain compares to the original E. coli strain. What is the maximum 2,3 BDO
yield that can be achieved from 1 mol/h of CO feeding before further strain
design Compare with part B. What is the maximum biomass yield from 1
mol/h of CO feeding 7 marks
E) Perform strain design of your mutant E. coli strain, assessing the maximum
biomass and 2,3 BDO yields obtained in a 1-stage process. Compare the E.
coli yield to the results of parts C and D. Employ a 2-stage process where the
first stage maximises growth and the second stage maximises 2,3 BDO
production. Critically discuss how a 2-stage process could be practically
achieved as well as the costs vs benefits of the 1-stage and 2-stage process
options. Which process option maximises the volumetric productivity of 2,3
BDO considering a common CO feed rate of 1 mol/L/h Remember to
describe in detail any assumptions made in your comparison and their
rationale. 9 marks
Written Presentation (4 marks)
Clearly Communicate your Work:
Please ensure that it is straight-forward for evaluators to follow your work, both in the
report and in the Excel file. Clearly explain your rationale for strain design and
comment on how you would propose to implement it. Show the methodology for your
calculations performed in the project. Present your written work in a concise, logical
sequence and be sure to include discussion around the results you are obtaining and
their significance.
Cite Previous Work:
If you are inspired by previous work of any kind, make sure you cite the work
properly. Likewise, if you need to show any images from research articles, make
sure they are attributed properly.
Graphics Should be Clear:
When using any graphics or figures, make sure the colours and font can be easily
seen by everyone. Focus on creating an informational graphic that can be readily
visualised and understood.
Presentation & Interview: 30 marks (+ Hurdle)
Each student will be asked to prepare an 8-minute presentation about their project.
Remember to present an overview/introduction of the process as well as relevant
details surrounding your models and strain designs. Note that you will be expected to
present your Excel file to the evaluators as well, including a brief demonstration of
one main output achieved when running the model. This will be followed by an 8-
minute interview period involving questions and answers about your presentation
and model with the evaluators, as well as relevant questions surrounding the
industry and research-based lectures of the course (weeks 10-13).
