Team:MichiganState/Design/Design
Project Design
Bioreactor Project Design
To begin, research was conducted to determine possible plastics to test and which types were used on campus. The testing initially started with Acrylonitrile Butadiene Styrene (ABS), Polylactic Acid (PLA), Standard Resin, and Dental Resin. These plastics were placed in test tubes with inoculated bacteria, Methylomicrobium alcaliphilum 20Z. Optical densities (OD) were taken every two hours to measure bacterial growth. More 20Z was cultured and inoculated with samples of Standard and Dental Resin, OD’s were again taken to measure bacterial growth. To get more accurate results, White Standard Resin, Black Standard Resin, Clear Resin, Dental Resin, and High-Temperature Resin were tested to observe the effects of pigmentation and dye on the bacteria and its growth. Four samples of each plastic were used, two were placed on shakers and two were placed in a still, sterile environment, with access oxygen.
Testing began next with White, Dental, and High-Temperature Resin with Methylorubrum extorquens AM1 instead of 20Z. This was done because AM1 grows much faster than 20Z, it is more visible, and our PI had a lot of experience with the strain. These factors would allow for more accurate results. All test tubes were placed on a shaker and OD’s were measured regularly.
After selecting resins, specifically Dental and High-Temperature resin, a biofilm was grown on a cross-section of the bioreactor. Twenty agar plates were used. ten of the plates were grown with PA1 as a test and ten were grown with AM1. Within the ten plates of each bacteria, five plates had cross-sections of the Dental Resin and five plates had cross-sections of the High-Temperature Resin. M. extorquens PA1 was used as a test because it is very similar to AM1 but grows much faster. The plates were left in a 38 oC incubator throughout the process. They were refed with methane every day to keep the bacteria growing.