Team:UCL/Science/Bioprocessing

From 2014.igem.org

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<li class="selected"><a href="#view1">Basics</a></li>
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<li class="selected"><a href="#view1">Methods today</a></li>
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<h4>Conventional industrial scale azodye treatment</h4>  
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<h4>Challenges in the textile industry</h4>
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<p>The global production of dyestuff amounts to over millions of tons per year. Azodyes represent two thirds of this value, a majority of which find their way to wastewater effluent streams. Characterized by the presence of one or more azo group (more), this type of organic colorant is also found in cosmetics, pharmaceuticals and food industries. While azodyes are a dye-class of choice in the textile industry, their global consumption is taking a toll on the environment.</p>
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<h4>Conventional textile effluent treatment process</h4>
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<br><p>The considerable structural diversity and recalcitrant nature of Azodyes make traditional wastewater treatment technologies markedly ineffective. Hence there exists an array of methods that deal with the removal of synthetic dyes from dyestuff-rich effluents, in order to reduce their environmental impact. These include large-scale physio-chemical processes outlined in the flow sheet below and a variety of organic/inorganic-support based adsorption and photocatalytic and oxidative decolourisation. The latter are however more recent methods that are currently too expensive and not scalable to production scales.</p>
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<br><b>General process flowsheet for wastewater of a wastewater treatment plant</b>
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<br><b>Screening</b> – ‘separation of particles on the basis of size i.e. removing dyeing process debris which may damage equipement’
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<br><b>Equalization</b> – ‘Reducing the variability in composition of textile waste prior to treatment’
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<br><b>Neutralization: pH control</b> – ‘Reduce downstream consumption of chemicals for used in the physiochemical stages i.e. coagulation and flocculation’
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<br><b>Coagulation</b> – ‘Used to remove waste materials in suspended or colloidal form’
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<br><b>Flocculation</b> – ‘Converts finely divided suspended solids into larger particles so that efficient, rapid settling can occur’
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<br><b>Primary treatment</b> – ‘gravity seperation/clarification/sedimentation unit to separate larger solid particles
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<br><b>Secondary treatment</b> – ‘removing/reducing concentration of organic and inorganic compounds through microbial decomposition’
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Revision as of 19:16, 15 October 2014

Goodbye Azodye UCL iGEM 2014

Sustainable Bioprocessing

Our Design Process

We will use rapid polymer prototyping techniques to generate microfluidic chips that will allow us to test our reaction and aid in the construction of a realistic bioprocess, which can be successfully scaled-up for industrial use. As we optimise and change our bioprocess, we can also quickly design new microfluidic chips that can mimic its development on a micro-scale. For example, it is our goal to integrate multiple downstream steps, such as chromatography, in order to isolate potential useful products. Demonstrating this in a microfluidic system is less time-consuming and far more cost effective than doing so at a larger scale.


For our microfluidic bioreactor, we will be using a magnetic free floating bar as our mixing system. This is an effective method of mixing at a microfluidic scale, as demonstrated in the video on the right. This video is of a microfluidic chemostat bioreactor designed by Davies et al. 2014 UCL, using a free-floating bar to mix two dyes.



Above are some examples of the microfluidics devices developed by our team for use in the lab at the UCL ACBE. The devices are initially designed using AutoCAD (2D and 3D computer-aided design software), once the designs are finalised they can be 3D-printed using the facilities provided by the UCL Institute of Making and UCL ACBE; allowing our bioprocess and laboratory team to experiment and improve designs.


An example of one of our microfluidic devices designed on AutoCAD can be downloaded here. This device utilises the basic concept of mixing the cells and dyes, producing a single output stream; much alike to the bioprocessing concept. During the course of designing the microfluidic device, several key considerations must be taken into account: ability to withstand high pressure without leakage; materials of construction to be inert and transparent; size constraints of inlet and outlet piping; ability to accurately 3D-print the device.


Why Bioprocessing?

Bioprocess engineering is a conglomerate of fields and is extensively employed to optimize a variety of production processes. In order to cope with market forces, industries for example the pharmaceutical, have had to considerably improve their bioprocessing tools and techniques. As a result a range of novel process alternatives have been developed to harness product-specific properties, each bearing benefits, disadvantages and costs. While these can be used to drive financial returns, biological processing is becoming a gateway to eco-friendly alternatives for the treatment of recalcitrant wastewater such as industrial effluents. By providing more flexibility in supporting efficient degradation of toxic compounds and having lower operating costs, the biological treatment process brings forward key advantages over it's traditional counterpart.
A typical bioprocess involves the fermentation of a stock culture (e.g. E. coli) at a small scale which is subsequently scaled up to suitable production capacities. The products from the fermentative stages are consequently separated and purified using a variety of unit operations designed to exploit the orthogonal properties of desired products. These can then be formulated into their ultimate delivery form.




The design of a successful bioprocess requires careful analysis of the many factors that impact choice of design parameters and process variables. It is crucial to consider the cost of the process at each stage to assess it's large scale feasibility.

Let's look at an example bioprocess
1. Upstream: Production bioreactor preceded by small-scale seed fermenters
2. Downstream: constitutes of three main stages
- Recovery relates to primary unit operations i.e. centrifugation and filtrations. The main goal is to concentrate the desired compound within the process stream by reducing volumes and removing fermentation byproducts.
- Purification involves unit operations such as chromatography, crystallization and ultrafiltration. The final stages are necessary to ensure purity requirements are met.
- Formulationinvolves the integrating of the product into the target delivery route followed by packaging and storage.

Contact Us

University College London
Gower Street - London
WC1E 6BT
Biochemical Engineering Department
Phone: +44 (0)20 7679 2000
Email: ucligem2014@gmail.com

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