This class is taught by Dr. Crowthers and assists in a long-term science fair project that runs over the course of five months. Classes offer insight into good brainstorming skills, sending professional emails, and using strategies to form a feasible science fair project idea for the upcoming science fairs. By encouraging finding topics that truly interest us, this class is a great way to explore different areas of interest and do individualized research on that area to identify and solve a problem.
Using alternative food sources as replacement culture mediums to grow Komagataeibacter hansenii, a commonly used species of bacterial cellulose, is not only a more cost-efficient approach, but has significant environmental benefits as it takes food that would typically be wasted and uses it in a meaningful way. From testing with mango peel extract, a higher yield of cellulose was evident in comparison to frequently used costly culture mediums. An XRD analysis displayed evidence that the cellulose produced from the mango peel medium had similar crystallinity to the cellulose produced from the HS Media, meaning there was a greater chance the mechanical properties of the cellulose were retained, adding to the overall point that this is a sustainable and beneficial approach to growing bacterial cellulose for its multitude of worldly applications.
Abstract: Bacterial cellulose is a biomaterial whose various structural properties allow for versatility in its designs and worldly applications in the medical, food, and cosmetics fields. This project focused on a commonly used cellulose producing strain, Komagataeibacter hansenii. High cost is the key drawback regarding how this species of bacteria is typically grown, particularly when translating this process to larger scale production. The cost of the culture medium itself can account for approximately 30% of the production cost. This project focused on further building on past research by identifying how replacing the typically used culture medium, Hestrin-Schramm, with an alternative food waste source, would affect the growth and production of Komagataeibacter hansenii. Preliminary testing utilized pineapple juice as a culture medium to simulate replacing the HS medium and how it would impact the yield. The juice was sterilized, combined with inoculum in six-well plates, and after resting in the incubator, an 83.27% increase was observed in cellulose yield from the Hestrin-Schramm medium to the pineapple juice medium. From there, leftover mango peels were used as a food waste culture medium and underwent an XRD analysis to compare its crystallinity patterns with the HS media cellulose. The results shed light on the efficacy of using mango peels as a successful culture medium replacement as the peaks on the graph were similar in both samples. Further testing needs to be initiated to observe how other properties are affected by this change, particularly ones that affect its biomedical applications.
How does changing the culture medium with alternate food sources affect the growth and resulting properties of Komagataeibacter hansenii?
If Komagataeibacter hansenii is grown in a medium formulated from food waste in place of the typical Hestrin-Schramm medium, then there will be improved production of bacterial cellulose. Not only that, but this will be a sustainable and cost-friendly alternative approach to growing the biomaterial, making it further accessible for use in various biomedical applications.
Figure 1: Bar graphs representing the average cellulose yields from the mango peel medium (represented by the blue graph; average of 8 samples grown in 50% mango peels and 50% HS media) and the HS Media (represented by the purple graph; average of 8 samples grown in 100% HS Media)
Figure 2: Line graphs representing the XRD analysis of both the HS media produced cellulose (lighter line) and the mango waste media produced cellulose (darker line). The key takeaway from this graph is identifying where the peaks in each graph are located and seeing if they remain similar between the two lines.
Figure 3: Bar graph displaying the average weights of cellulose produced through different culture mediums. Bar one signifies the 100% pineapple juice medium, bar two represents the 50% juice and 50% HS medium mix, and bar three represents the 100% HS medium. From the bar graph, there is a clear decline in cellulose production as the concentration of pineapple juice decreases.
Figure 4: Line graph representing the specific wet weights of cellulose produced through different culture mediums. As a whole, the line displaying the cellulose grown in a 100% pineapple juice medium has the highest numbers, indicating that it had the greatest cellulose yield, particularly in comparison with the 100% HS medium line.