Cost and Ease of Use

Abstract

The fact of the matter is, no matter how good Cellucoat as a material may function, we are attempting to bring it into the market as a product. This is why we needed to consider how viable it could be in the market. One factor we needed to take into consideration when comparing Cellucoat to other packaging materials like plastic or paper is that our material is “active” packaging, meaning that besides the physical protection the packing itself provides there is additional protection applied. With the incorporation of antimicrobial peptides in the cellulose fibres we can protect the fruit from spoilage longer by keeping bacterium at bay. This fact influences the “bang for your buck” factor of Cellucoat. Another important point to make note of is the production cost of Cellucoat. Our subproject, fruit waste media (FWM) focuses on just that, using fruit waste and breaking it down to supplement the carbon source in HS media (the growth media used in our coculture). Calculating the Bc yields we were able to produce from growth tests with FWM we found that we could reduce the cost of production by 60%. With the cost and functionality of the product considered we can look at how to make Cellucoat a better analog for clamshell packaging. BioSculpting is a major part of this consideration, how we have designed the molds and the physcial processing of our BC is what is seen as the final product by our users. There are a whole host of considerations that go into this, one of them being how we strentnten BC through PHB interjected within the cellulose structure. This along with molding gives us a strong, more rigid box that better matches what is used in supermarkets. More aesthetic factors are also held in mind as we have developed techniques to bith add transparency and colour to Cellucoat, these are things that can influence how fruit are perceived on store shelves and the option to have this level of customizability gives companies flexibility to have BC more tailored to their specific desires. There are many levels that the BC must be viable in order for it to break into this market and the time and energy spent on all of them gives us the ability to put Cellucoat’s best foot forward.

Despite all of the advantages of BC over polymers of plant origin, its production is a relatively expensive process. This is due primarily to the low productivity of known strains and expensive culture media. Due to this, it is imperative to investigate the costs associated with bacterial cellulose production, particularly in the context of a co-polymer with integrated PHB and nisin. Furthermore, this has further implications as Cellucoat intends for their BC to be competitive with current plastic products, presenting a viable and competitive alternative. In addressing these shortcomings, Cellucoat has proposed multiple avenues if reducing BC production cost, such as using fruit waste media and optimizing efficiency through the use of a co-culture.

Investigate Previous Design Solutions

Currently, single use plastics are being banned in Canada and other nations such as France, Spain, the UK, and India by 2030 and are being replaced by environmentally friendly alternatives (1). These plastic alternatives, which are reusable, biodegradable, or compostable can increase the cost of packaged produce up to 266% compared to produce packaged by plastics (2). The steep price tag is not the only thing on consumers' minds (2). Plastics are consumer friendly being a water resistant, sturdy, transparent, and aesthetic material. PlusPack (3), a plastic food packaging company has their products demonstrating the advantages that the 20th and 21st century have become to love about plastics as an ideal food packaging material:

Table 1. Table comparing the product performance and product price according to figures acquired from Plus Pac’s Website (3). Calculations for price were determined as an average of approximately 80 packages. The prices listed are the cost of individual units, each of which weigh 0.12 g - 150 g.

In the past decade, there has been a push for more environmentally friendly and sustainable plastic packaging alternatives. This caused the rise of companies that create compostable packaging materials that are derived from PLA (polylactic acid) and other biomaterials (5). However, not all biodegradable materials are compostable. This means biodegradable bioplastics will occupy space in landfills just like plastic. Good Start Packaging provides a breadth of products made from biodegradable and compostable materials, including bioplastics, paper, and cardboard (5).

Table 2. Table comparing the product performance and product price according to figures acquired from Good Start Packaging’s Website (5). Calculations for price were determined as an average of approximately 200 packaging units. The prices listed are the cost of individual units, each of which weigh about 0.12 g - 150 g.

Developing Process

Initial Design Informed By Customer Discovery

After conducting a series of customer discovery interviews across several parts of our hypothesized supply chain, we concluded our buyers to even the end users. This revealed that consumers want an alternative to plastic packaging, specifically clamshells used for fruit packaging. They also require an easier process to preserve fruit for longer. Wholesalers and retailers also communicated that plastic packaging was excessive and were taking proactive steps in reducing plastic use at their stores. While produce packaging companies said that for Cellucoat to be advantageous in the industry we have to have the strength and economic advantage that plastic packaging has in comparison to its other competitors. This helped to inform our design for our industry.

The Cellucoat process starts with it being produced in an industrial lab. This process involves firstly sourcing constituents (fruit waste) of the modified growth media, which is fruit waste media from farmers, retailers, and consumers. Then our co-culture to produce the desired bacterial cellulose material is grown. After the growth period the BC is harvested, sterilized and post-processing modifications are then conducted. To get the BC to be the shape of our desired produce package, Bio Sculpting is then conducted. Lastly, shipping of the material to the desired location occurs.

In our case, the material is shipped to produce packaging companies or other parties that pack fresh produce such as farms. This establishes produce-packaging companies and such parties as our buyers. These companies would pack the fruits they receive or produce in the package. These packaged fruits are then transported in rail cars, and trucks to wholesale and retail stores for sale to consumers. Consumers purchase their fruits in Cellucoat packaging capable of prolonging the shelf life of their fruit thus reducing fruit waste and money loss. After the produce is consumed, Cellucoat goes into the compost bin and is degraded. However, any fruit not preserved has the potential to be used as the source material for the production of Cellucoat., thus creating a “cradle-to-cradle” system.

Prototype #1: Reducing Costs Associated with Production

We needed to determine the costs associated with producing Cellucoat, so we conducted a financial analysis. Through this analysis, we found that the total start-up cash needed for the business is $19,201,035.56.

As seen, this is highly capital intensive which can be attributed to the cost of the media used to grow the bacteria. This was the motivation for us utilizing the fruit waste media as through HP, we discovered that for Cellucoat to be implemented as produce packaging, it has to be cost-attractive. To determine if our modified media made from fruit waste reduced the production costs of Cellucoat, we conducted a cost analysis. We performed the analysis by calculating the cost of producing BC based on the costs of the media for several iterations of the experiments.

From the analysis, we discovered that glucose makes up about 33% of media costs. Hence, if we could make the glucose cost zero, we would reduce production costs by 33%. The usage of fruit waste could be made more efficient via the use of enzyme catalysts to break down the more complex sugars into glucose. After running experiments from our analysis, we realized that we were able to reduce the cost of production by 60% instead of 33%. This was from modified media consisting of 45% FWM and 55% HS. We can also conclude that since this media still contains HS media, we hypothesize that reducing the amount of HS and maximizing BC yield could help us further reduce the costs of BC production. Ultimately, reducing the costs would make Cellucoat more economically advantageous.

Prototype #2: Making Cellucoat Transparent and Providing Color Customization

Packaging traditionally features bright, vibrant colours, and fruit packaging is no exception. These colours help to catch the attention of consumers, leading to a stronger brand identity and more purchases. After meeting with Chris Clark, Category Director of Star Produce, we realized the immense value that colour has in the packaging industry; Chris asserted that people shop with their eyes. This extended to characteristics such as transparency, a trait valued by consumers as it allows for more informed decisions regarding the quality of the fruit. To increase our appeal to both produce packaging companies and to the average consumer, developing ways to colour our BC alongside methods of increasing transparency became an important part of the project.

Bacterial cellulose naturally takes the colour of the growth media as it is produced. Because of this, BC typically takes various shades of yellow and brown, depending on the exact composition of the media. This is sub-optimal for a packaging solution, as brown is a naturally unexceptional colour relative to the multicoloured inks and vivid hues used in cardboard and plastic packaging. To mitigate this, we consulted with trend researcher Juliana Schneider and developed a natural dye developed from red cabbage extract. This dye proved to be effective at colouring our BC without compromising composability while also offering access to a wide range of colours through its status as a natural pH indicator. However, in order to expand to colours that exist beyond the range of the red cabbage dye, other natural dyes are being explored as future alternatives.

Transparency, on the other hand, was derived from the purification process. We explored a variety of methods and techniques, aiming to produce the clearest, whitest BC to achieve the desired translucency. We iterated on our techniques using our experimental results and existing literature. Though purification of BC using hydrogen peroxide provided the most clear, desirable samples, we opted to purify our BC using a sodium bicarbonate wash. Though the resulting BC was less transparent, the sodium bicarbonate helped to increase the BC’s ability to resist cellulase degradation. Because of this, we made the decision to compromise on transparency to increase the lifespan and the long-term structural strength of our BC.

Prototype #3: Replacing Clam Shells with Cellucoat

Bacterial cellulose, as a biomaterial, has only been explored in a limited capacity outside of a laboratory environment. Thus, creating a large-scale prototype proved to be a novel task with many challenges. Taking further advice from Chris, we decided that our prototype needed to be focused on replacing a single type of plastic packaging; adapting a working proof-of-concept to other situations is much easier than developing many new solutions in parallel. We chose plastic clamshell packaging -- often used for small fruits and berries -- due to their ubiquity and, more importantly, the lack of sustainable options in the field. This choice allows us to focus on a single packaging type while still making a sizable impact in the industry.

Though initial prototyping involved rudimentary boxes constructed over simple molds, we quickly had to iterate and expand our workflow to produce a packaging with sufficient strength to serve as a real plastic alternative. To help create the packaging, we developed a series of processes known as BioSculpting in order to maximize the strength of pure BC. In doing so, we explored the creation of BC cardboard, utilizing some of the developments in cardboard design and applying them to our biomaterial. By layering the BC on top of a corrugated middle piece, we were able to substantially strengthen our project without adding excessive complexity to the production or manufacturing process. This allowed for boxes to be constructed that had comparable strength to more traditional forms of packaging. These methods were further refined as the project continued to minimize the wastage of material, improve the mechanical properties, and allow for flexibility in design to create a packaging solution that can easily be modified or changed to suit the needs of a fruit packaging company.

Prototype #4: Improving Mechanical Strength

Cellucoat was born out of a desire to create an antimicrobial produce packaging. However, our team also had to consider aspects beyond the packaging material and components and look at how the package would be used to protect produce during distribution, retail, home environments and travel. Christopher Clark, Category Director of Star Produce has extensive experience with different types of packages and how it works from distribution centers where he works where a majority of produce is packaged, to retailers. He provided a unique outlook on how we should not only make the packaging appealing to consumers, but to retailers and distributors so they want to purchase the packaging.

To best appeal to Cellucoat’s user’s needs, Christopher stated that when designing produce packaging you have to consider:

Christopher emphasized the importance of ensuring that the packaging is strong enough to be stacked and survive compressive forces during shipment. This meant that Cellucoat not only had to be mechanically strong, but it also had to be water resistant so that moisture would not compromise the integrity of the packaging during shipment.

BC as a material has a core problem: poor mechanical strength and water absorption. Bacterial cellulose, when less than 2 mm thick, is 500x weaker than plastic of the same thickness, and has a strength akin to that of paper. So our team has to consider that the resource-intensive process of BC is not warranted if it produces a material that absorbs as much water and has similar mechanical strengths as paper. After all, packaging has to undergo many mechanical stresses throughout the transportation journey and the added issue of the material absorbing moisture from the produce causing the packaging to lose shape is not ideal.

To improve the mechanical strength and decrease the hydrophilicity of BC, our team decided to look into additives to integrate into the material, similar to plasticizers. Our aim was to find a substance that could be added to the BC without compromising the compostability and would be homogeneously distributed throughout the material. Our search focused on integrating a biopolymer known as Polyhydroxyalkanoates (PHA) into our BC material to create a more durable and water-resistant material (7), which according to Christopher Clark, are ideal properties for packaging that follows produce through shipment.

However, there are many types of PHAs, all of which fall under the category of being degradable, biocompatible, thermoplastic polyesters derived from microorganisms, used as a reserve of carbon and energy (7). What our team paid the greatest attention to was the capacity to be recombinantly integrated into our BC and the material that has the greatest capacity to improve the properties of BC as a nanocomposite. Our team decided on polyhydroxybutyrate (PHB) because it has been successfully recombinantly expressed by teams in the past and literature has indicated specifically that PHB and BC nanocomposite properties are more durable and water-resistant than the materials alone (8).

Future Considerations

The costs of producing bacterial cellulose products at an industrial scale are highly capital intensive and have limited large-scale production of bacterial cellulose. Hence, to ensure that Cellucoat is feasible we would be taking several steps to allow for this. The culture media used to grow the bacterial cellulose bacteria, K.xylinus is one of the major cost expenses. Therefore our team worked on a modified media called Fruit waste media to grow our bacterial cellulose-producing bacteria. This media is from orange fruit waste and reduces the costs associated with growth media. However, it still contains constituents of the traditional HS media. The presence of HS media still increases the costs, especially when taken to an industrial level. Therefore, there is a need to develop a modified media that uses little to no conventional media to reduce the cost.

Low BC yields are also another reason why it is difficult to establish it in the industry. Thus creating a bioreactor designed for the adequate growth of K.xylinus and E.coli would be an ideal solution to tackle this problem. The literature suggests several suggestions for an aerosol bioreactor that uses a similar design to that we use at a lab scale to produce bacterial cellulose. Implementing a similar design can help maximize our BC yield.

Conclusion

After various stakeholder input, we decided to implement a coculture of PHB and BC nanocomposite material to improve mechanical strength. In developing a competitive plastic alternative, various prototypes were explored in the design process. Namely, reducing costs associated with production, making Cellucoat transparent and providing color customization, replacing clam shells with Cellucoat, and improving mechanical strength, making Cellucoat a competitive alternative to conventional plastic.

References

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